tag:theconversation.com,2011:/global/topics/omicron-variant-114065/articlesOmicron variant – The Conversation2023-11-20T22:13:55Ztag:theconversation.com,2011:article/2178042023-11-20T22:13:55Z2023-11-20T22:13:55ZWhat are the new COVID booster vaccines? Can I get one? Do they work? Are they safe?<figure><img src="https://images.theconversation.com/files/559796/original/file-20231116-15-2n01o.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1000%2C561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-senior-laughing-after-vaccinated-ideas-2001444137">Shutterstock</a></span></figcaption></figure><p>As the COVID virus continues to <a href="https://pubmed.ncbi.nlm.nih.gov/36680207/">evolve</a>, so does our vaccine response. From <a href="https://www.health.gov.au/ministers/the-hon-mark-butler-mp/media/new-covid-19-vaccines-available-to-target-current-variants?language=en">December 11</a>, Australians will have access to <a href="https://www.health.gov.au/news/atagi-recommendations-on-use-of-the-moderna-and-pfizer-monovalent-omicron-xbb15-covid-19-vaccines?language=en">new vaccines</a> that offer better protection. </p>
<p>These “monovalent” booster vaccines are expected to be a <a href="https://theconversation.com/cdc-greenlights-two-updated-covid-19-vaccines-but-how-will-they-fare-against-the-latest-variants-5-questions-answered-213341">better match</a> for currently circulating strains of SARS-CoV-2, the virus that causes COVID.</p>
<p>Pfizer’s monovalent vaccine will be <a href="https://www.health.gov.au/ministers/the-hon-mark-butler-mp/media/new-covid-19-vaccines-available-to-target-current-variants?language=en">available</a> to eligible people aged five years and older. The Moderna monovalent vaccine can be used for those aged 12 years and older.</p>
<p>Who is eligible for these new boosters? How do they differ from earlier ones? Do they work? Are they safe?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/were-in-a-new-covid-wave-what-can-we-expect-this-time-216820">We're in a new COVID wave. What can we expect this time?</a>
</strong>
</em>
</p>
<hr>
<h2>Who’s eligible for the new boosters?</h2>
<p>The federal government has accepted the Australian Technical Advisory Group (ATAGI) recommendation to use the new vaccines, after Australia’s regulator <a href="https://www.tga.gov.au/products/covid-19/covid-19-vaccines/covid-19-vaccines-regulatory-status">approved their use last month</a>. However, vaccine eligibility has remained the same since September. </p>
<p>ATAGI <a href="https://www.health.gov.au/news/atagi-recommendations-on-use-of-the-moderna-and-pfizer-monovalent-omicron-xbb15-covid-19-vaccines?language=en">recommends</a> Australians aged over 75 get vaccinated if it has been six months or more since their last dose. </p>
<p>People aged 65 to 74 are recommended to have a 2023 booster if they haven’t already had one. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=315&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=315&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=315&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=396&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=396&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560533/original/file-20231120-21-4igdnx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=396&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For people without risk factors.</span>
<span class="attribution"><a class="source" href="https://www.health.gov.au/sites/default/files/2023-10/atagi-recommended-covid-19-vaccine-doses.pdf">Health.gov.au</a></span>
</figcaption>
</figure>
<p>Adults aged 18 to 64 <em>with</em> underlying risk factors that increase their risk of severe COVID are also recommended to have a 2023 booster if they haven’t had one yet. And if they’ve already had a 2023 booster, they can consider an additional dose. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=311&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=311&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=311&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=391&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=391&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560532/original/file-20231120-26-70jfyr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=391&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Advice for people with risk factors.</span>
<span class="attribution"><a class="source" href="https://www.health.gov.au/sites/default/files/2023-10/atagi-recommended-covid-19-vaccine-doses.pdf">Health.gov.au</a></span>
</figcaption>
</figure>
<p>For adults aged 18 to 64 <em>without</em> underlying risk factors who have already received a 2023 booster, an additional dose isn’t recommended. But if you’re aged 18 to 64 and haven’t had a booster in 2023, you can consider an additional dose. </p>
<p>Additional doses aren’t recommended for children <em>without</em> underlying conditions that increase their risk of severe COVID. A primary course is not recommended for children aged six months to five years <em>without</em> additional risk factors. </p>
<h2>Monovalent, bivalent? What’s the difference?</h2>
<p><strong>From monovalent</strong></p>
<p>The initial COVID vaccines were “monovalent”. They had one target – the original viral strain.</p>
<p>But as the virus mutated, we assigned new letters of the Greek alphabet to each variant. This brings us to Omicron. With this significant change, we saw “immune evasion”. The virus had changed so much the original vaccines didn’t provide sufficient immunity.</p>
<p><strong>To bivalent</strong> </p>
<p>So vaccines were updated to target an early Omicron subvariant, BA.1, plus the original ancestral strain. With two targets, these were the first of the “bivalent” vaccines, which were approved in Australia <a href="https://theconversation.com/omicron-specific-vaccines-may-give-slightly-better-covid-protection-but-getting-boosted-promptly-is-the-best-bet-190736">in 2022</a>.</p>
<p>Omicron continued to evolve, leading to more “immune escape”, contributing to repeated waves of transmission.</p>
<p>The vaccines were updated again in <a href="https://theconversation.com/havent-had-covid-or-a-vaccine-dose-in-the-past-six-months-consider-getting-a-booster-199096">early 2023</a>. These newer bivalent vaccines target two strains – the ancestral strain plus the subvariants BA.4 and BA.5.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-covid-inquiry-has-been-announced-but-is-covid-still-a-thing-do-i-need-a-booster-213469">A COVID inquiry has been announced. But is COVID still a thing? Do I need a booster?</a>
</strong>
</em>
</p>
<hr>
<p><strong>Back to monovalent</strong></p>
<p>Further changes in the virus have meant our boosters needed to be updated again. This takes us to the recent announcement.</p>
<p>This time the booster targets another subvariant of Omicron known as XBB.1.5 (sometimes known as <a href="https://theconversation.com/the-kraken-subvariant-xbb-1-5-sounds-scary-but-behind-the-headlines-are-clues-to-where-covids-heading-198158">Kraken</a>).</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1621375840284983296"}"></div></p>
<p>This vaccine is monovalent once more, meaning it has only one target. The target against the original viral strain has been removed.</p>
<p>According to advice given to the World Health Organization <a href="https://www.who.int/news/item/18-05-2023-statement-on-the-antigen-composition-of-covid-19-vaccines">in May</a>, this is largely because immunity to this original strain is no longer required (it’s no longer infecting humans). Raising immunity to the original strain may also hamper the immune response to the newer component, but we’re not sure if this is occurring or how important this is.</p>
<p>The United States <a href="https://theconversation.com/cdc-greenlights-two-updated-covid-19-vaccines-but-how-will-they-fare-against-the-latest-variants-5-questions-answered-213341">approved</a> XBB.1.5-specific vaccines from Pfizer and Moderna in <a href="https://www.fda.gov/news-events/press-announcements/fda-takes-action-updated-mrna-covid-19-vaccines-better-protect-against-currently-circulating">mid-September</a>. These updated vaccines have also been <a href="https://www.tga.gov.au/sites/default/files/2023-10/auspar-spikevax-xbb.1.5-231012.pdf">approved in</a> places including Europe, Canada, Japan and Singapore.</p>
<p>In Australia, the Therapeutic Goods Administration (TGA) approved
them <a href="https://www.tga.gov.au/products/covid-19/covid-19-vaccines/covid-19-vaccines-regulatory-status">in October</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/beyond-covid-vaccines-what-else-could-mrna-technology-do-for-our-health-215142">Beyond COVID vaccines: what else could mRNA technology do for our health?</a>
</strong>
</em>
</p>
<hr>
<h2>Do these newer vaccines work?</h2>
<p>Evidence for the efficacy of these new monovalent vaccines comes from the results of research <a href="https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent=&id=CP-2023-PI-02409-1&d=20231117172310101">Pfizer</a> and <a href="https://www.tga.gov.au/resources/auspar/auspar-spikevax-xbb15">Moderna</a>
submitted to the TGA.</p>
<p>Evidence also comes from a <a href="https://www.medrxiv.org/content/10.1101/2023.08.22.23293434v2">preprint</a> (preliminary research available online that has yet to be independently reviewed) and an update Pfizer <a href="https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2023-09-12/10-COVID-Modjarrad-508.pdf">presented</a> to the US Centers for Disease Control.</p>
<p>Taken together, the available evidence shows the updated vaccines produce good levels of antibodies in <a href="https://www.tga.gov.au/resources/auspar/auspar-spikevax-xbb15">laboratory studies</a>, <a href="https://www.medrxiv.org/content/10.1101/2023.08.22.23293434v2">in humans</a> and <a href="https://www.tga.gov.au/resources/auspar/auspar-spikevax-xbb15">mice</a> when compared to previous vaccines and when looking at multiple emerging variants, including EG.5 (sometimes known as <a href="https://theconversation.com/the-who-has-declared-eris-a-variant-of-interest-how-is-it-different-from-other-omicron-variants-211276">Eris</a>). This variant is the one causing high numbers of cases around the world currently, including in Australia. It is very similar to the XBB version contained in the updated booster. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1689763106791297024"}"></div></p>
<p>The updated vaccines should also cover <a href="https://theconversation.com/how-evasive-and-transmissible-is-the-newest-omicron-offshoot-ba-2-86-that-causes-covid-19-4-questions-answered-212453">BA.2.86 or Pirola</a>, according to <a href="https://www.tga.gov.au/sites/default/files/2023-10/auspar-spikevax-xbb.1.5-231012.pdf">early results</a> from clinical trials and the US <a href="https://www.cdc.gov/respiratory-viruses/whats-new/covid-19-variant.html">Centers for Disease Control</a>. This variant is responsible for a rapidly increasing proportion of cases, with case numbers growing <a href="https://twitter.com/BigBadDenis/status/1725310295596560662?s=19">in Australia</a>.</p>
<p>It’s clear the virus is going to continue to evolve. So performance of these vaccines against new variants will continue to be closely monitored.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-evasive-and-transmissible-is-the-newest-omicron-offshoot-ba-2-86-that-causes-covid-19-4-questions-answered-212453">How evasive and transmissible is the newest omicron offshoot, BA.2.86, that causes COVID-19? 4 questions answered</a>
</strong>
</em>
</p>
<hr>
<h2>Are they safe?</h2>
<p>The <a href="https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent=&id=CP-2023-PI-02409-1&d=20231117172310101">safety</a> of the updated vaccines has also been shown to be similar to previous versions. Studies <a href="https://www.medrxiv.org/content/10.1101/2023.08.22.23293434v2">comparing them</a> found no significant difference in terms of the adverse events reported.</p>
<p>Given the availability of the updated vaccines, some countries have removed their approval for earlier versions. This is because newer versions are a closer match to currently circulating strains, rather than any safety issue with the older vaccines.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/do-covid-boosters-cause-more-or-fewer-side-effects-how-quickly-does-protection-wane-your-questions-answered-176695">Do COVID boosters cause more or fewer side effects? How quickly does protection wane? Your questions answered</a>
</strong>
</em>
</p>
<hr>
<h2>What happens next?</h2>
<p>The availability of updated vaccines is a welcome development, however this is not the end of the story. We need to make sure eligible people get vaccinated.</p>
<p>We also need to acknowledge that vaccination should form part of a comprehensive strategy to limit the impact of COVID from now on. That includes measures such as mask wearing, social distancing, focusing on ventilation and air quality, and to a lesser degree hand hygiene. Rapidly accessing antivirals if eligible is also still important, as is keeping away from others if you are infected.</p><img src="https://counter.theconversation.com/content/217804/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Griffin is a director and scientific advisory board member of the Immunisation Coalition and has previously had roles as an advisory board member for Pfizer, Moderna and Novavax. </span></em></p>As the virus continues to mutate, COVID vaccines are updated. This brings us to the latest announcement about the new ‘monovalent’ vaccines.Paul Griffin, Professor, Infectious Diseases and Microbiology, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2133412023-09-13T03:02:02Z2023-09-13T03:02:02ZCDC greenlights two updated COVID-19 vaccines, but how will they fare against the latest variants? 5 questions answered<figure><img src="https://images.theconversation.com/files/547878/original/file-20230912-25-hdh9ud.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5455%2C3596&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The CDC expects the updated shots to be effective at preventing severe COVID-19, even in the face of new variants.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/covid-19-coronavirus-booster-vaccination-concept-royalty-free-image/1334441038?phrase=new+booster+shot&adppopup=true">Teka77/iStock via Getty Images Plus</a></span></figcaption></figure><p><em>On Sept. 12, 2023, the Centers for Disease Control and Prevention <a href="https://www.nytimes.com/2023/09/12/health/covid-cdc-vaccines.html">recommended the newly formulated COVID-19 vaccines</a> for <a href="https://www.cdc.gov/media/releases/2023/p0912-COVID-19-Vaccine.html">all Americans ages 6 months and up</a>, hours after its expert advisory committee voted 13 to 1 in favor of recommending the vaccines.</em> </p>
<p><em>The CDC’s broad recommendation comes <a href="https://www.washingtonpost.com/health/2023/09/11/covid-vaccine-new-booster/">one day after</a> the Food and Drug Administration approved <a href="https://www.fda.gov/news-events/press-announcements/fda-takes-action-updated-mrna-covid-19-vaccines-better-protect-against-currently-circulating">Moderna’s and Pfizer’s updated mRNA vaccines</a> that target a previously dominant variant of the omicron family called XBB.1.5. The updated shots will be available to the public within days.</em></p>
<p><em>The Conversation asked <a href="https://scholar.google.com/citations?user=jJVj3sUAAAAJ&hl=en">Prakash Nagarkatti</a> and <a href="https://scholar.google.com/citations?user=af7TahQAAAAJ&hl=en">Mitzi Nagarkatti</a>, a husband and wife team of immunologists from the University of South Carolina, to weigh in on how the new vaccines might stand up against the latest COVID-19 variants that are swirling across the globe.</em> </p>
<h2>1. How are the new vaccines different from the previous?</h2>
<p>When the first vaccine against COVID-19 was rolled out in December 2020, it was designed as a monovalent vaccine, meaning that it was formulated against only the original SARS-CoV-2 virus. That vaccine, as well as the updated ones, target the spike protein, which the virus uses to infect our cells and cause the disease. </p>
<p>That design made sense before the virus began mutating into a <a href="https://theconversation.com/how-evasive-and-transmissible-is-the-newest-omicron-offshoot-ba-2-86-that-causes-covid-19-4-questions-answered-212453">complex family tree</a> of <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html">variants and sublineages</a>. But as the virus structure shifted over time, the antibodies produced in response to the original vaccine became less effective against the new variants.</p>
<p>This necessitated the development in 2022 of <a href="https://theconversation.com/will-omicron-specific-booster-shots-be-more-effective-at-combating-covid-19-5-questions-answered-189610">new “bivalent” vaccines</a> that targeted both the original strain of SARS‑CoV‑2 and new viral variants such as the omicron <a href="https://doi.org/10.1136/bmj.o1969">BA.4 and BA.5 lineages</a> <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">that were dominant in mid-2022</a>.</p>
<p>But, not surprisingly, new variants of the virus continued to emerge.</p>
<p>In June 2023, the FDA asked vaccine developers to <a href="https://www.fda.gov/vaccines-blood-biologics/updated-covid-19-vaccines-use-united-states-beginning-fall-2023">formulate new fall shots</a> to target the then-dominant XBB.1.5 subvariant.</p>
<p>The FDA <a href="https://www.fda.gov/news-events/press-announcements/fda-takes-action-updated-mrna-covid-19-vaccines-better-protect-against-currently-circulating">approved that monovalent mRNA-based vaccine</a> based on the overall efficacy data presented by the vaccine manufacturers.</p>
<p>Unfortunately, XBB.1.5 is no longer the dominant strain in the U.S.; it has been displaced by other variants from the XBB lineage, thereby <a href="https://time.com/6308418/ba-2-86-covid-19-variant-vaccine/">raising concerns about the potential efficacy</a> of the new shot. As of mid-September, <a href="https://covid.cdc.gov/covid-data-tracker/#variant-summary">the dominant variants nationwide are</a> EG.5, also known as Eris, followed by FL.1.5.1 – called Fornax – and XBB.1.16.6. </p>
<p>Meanwhile, a new <a href="https://theconversation.com/how-evasive-and-transmissible-is-the-newest-omicron-offshoot-ba-2-86-that-causes-covid-19-4-questions-answered-212453">highly mutated omicron offshoot, BA.2.86, nicknamed Pirola</a>, is making its way across the globe – albeit so far in small numbers. </p>
<h2>2. Who should get a new shot?</h2>
<p>The CDC recommended that everyone ages 6 months old and up should get an updated COVID-19 vaccine so that they can be better protected against developing serious outcomes from COVID-19, including hospitalization. The agency noted that people who received the 2022-2023 bivalent COVID-19 shot “saw greater protection against illness and hospitalization than those who did not.”</p>
<p>Most Americans will be able to get the newly formulated vaccine <a href="https://www.cdc.gov/media/releases/2023/p0912-COVID-19-Vaccine.html">at no cost</a>, according to the CDC.</p>
<p>The FDA approved a single shot of the updated vaccine <a href="https://www.fda.gov/news-events/press-announcements/fda-takes-action-updated-mrna-covid-19-vaccines-better-protect-against-currently-circulating">for anyone ages 5 and older</a> – regardless of whether they were previously vaccinated or not. The agency also approved unvaccinated individuals 6 months to 4 years of age to receive three doses of the updated Pfizer vaccine or two doses of the updated Moderna vaccine.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/AeDLftf6RVM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">For most people, doctors recommend getting both the COVID-19 and flu shots before the end of October.</span></figcaption>
</figure>
<h2>3. How effective could the updated shot be against the latest variants?</h2>
<p>Based on its current assessment, the CDC indicates that the BA.2.86 variant <a href="https://www.cdc.gov/respiratory-viruses/whats-new/covid-19-variant.html#">may be able to cause infection</a> even in people who have been previously vaccinated or those who have had COVID-19 infection in the past. But the CDC says it still expects the updated fall 2023 booster shot to be effective at reducing severe disease and hospitalization. </p>
<p>Moderna reported in August 2023 that the new monovalent mRNA COVID-19 vaccine gave a <a href="https://investors.modernatx.com/news/news-details/2023/Moderna-Clinical-Trial-Data-Confirm-Its-Updated-COVID-19-Vaccine-Generates-Robust-Immune-Response-in-Humans-Against-Widely-Circulating-Variants/default.aspx">“significant boost” in antibodies</a> that are protective against two of the currently circulating variants: EG.5 – which is responsible for most cases in the U.S. as of mid-September – and FL.1.5.1. Then, in early September, Moderna announced that its most recent data from human trials showed an 8.7-fold increase in neutralizing antibodies against the newest variant, BA.2.86, following vaccination with the updated shot.</p>
<p>Similarly, new <a href="https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-receive-us-fda-approval-2023-2024-covid">pre-clinical data from Pfizer shows</a> that its version of the new mRNA vaccine produced antibodies that were effective at neutralizing the XBB.1.5, BA.2.86 and EG.5.1 variants. </p>
<p>This early research suggests that the new mRNA vaccines – although developed specifically against XBB.1.5 – are still effective against some of the most prevalent variants.</p>
<p>Novavax, which specializes in traditional protein-based vaccines, <a href="https://ir.novavax.com/press-releases/2023-08-22-Novavaxs-Updated-Protein-based-XBB-COVID-Vaccine-Induced-Neutralizing-Responses-Against-Emerging-Subvariants%2C-Including-EG-5-1-and-XBB-1-16-6">also announced in August</a> that its updated COVID-19 vaccine directed against the XBB variant produced a broad neutralizing antibody response against key variants in animal studies. However, the company does not yet have data on its vaccine’s performance against two other key variants, FL.1.5.1 and BA.2.86. The Novavax vaccine has not yet gone up for FDA review, but its approval is also expected within months.</p>
<p>It is important to keep in mind that while all three vaccines have been shown to trigger antibodies that can neutralize most of the currently circulating variants, it is unclear whether the vaccines will be able to effectively prevent COVID-19 infection in humans. Such clinical studies are time-consuming, so given the urgency and speed needed to develop vaccines against the ever-changing COVID-19 variants, vaccine manufacturers rely on antibody levels as an indicator of protection. </p>
<h2>4. Is there a ‘right’ time to get the new vaccine?</h2>
<p>Antibodies produced after a COVID-19 infection or vaccination last for about six months, and then <a href="https://theconversation.com/how-long-does-protective-immunity-against-covid-19-last-after-infection-or-vaccination-two-immunologists-explain-177309">their levels start declining</a>. This is called “waning immunity.”</p>
<p>About a year after getting a COVID-19 infection or vaccination, only a small fraction of antibodies can be detected. This is why health care providers recommend getting another shot if a year has passed since you were vaccinated or had an active infection. </p>
<p>It has become very clear that vaccines against COVID-19 do not provide 100% protection against <a href="https://www.yalemedicine.org/news/covid-19-vaccine-comparison#">catching a new COVID-19 infection</a>, but they can make illness from the infection <a href="https://www.cdc.gov/media/releases/2021/p0607-mrna-reduce-risks.html">milder, shorter or both</a>.</p>
<p>In addition, vaccines provide <a href="https://www.cdc.gov/media/releases/2022/s0318-COVID-19-vaccines-protect.html">significant protection from hospitalization and death</a> and <a href="https://www.health.harvard.edu/diseases-and-conditions/vaccination-may-protect-against-long-covid#">may help protect against developing</a> <a href="https://www.cdc.gov/coronavirus/2019-ncov/long-term-effects/index.html">long COVID</a>. </p>
<p>Viral infections normally peak in the winter, which is <a href="https://www.webmd.com/vaccines/covid-19-vaccine/news/20230905/what-to-know-about-flu-covid-rsv-shots">why experts advise</a> getting both COVID-19 and flu vaccine shots in <a href="https://www.nytimes.com/article/flu-covid-rsv-vaccines.html">the months of September and October</a>. For convenience, the <a href="https://www.cdc.gov/flu/prevent/coadministration.htm">two shots can be safely taken</a> <a href="https://doi.org/10.1001/jamanetworkopen.2023.32813">at the same time</a>. This is because the immune cells that produce antibodies against one vaccine agent are distinct from those that produce antibodies against the other vaccine agent. </p>
<p>However, taking two different vaccines at the same time <a href="https://doi.org/10.1016/s0140-6736(12)61961-8">could cause more side effects</a>, such as fever, aches and pain. This is especially the case for people who have experienced such side effects in the past after taking the COVID-19 and flu vaccines separately.</p>
<p>In addition, a newly approved vaccine against the respiratory syncytial virus, or RSV, is now <a href="https://www.cdc.gov/vaccines/vpd/rsv/hcp/older-adults.html#">recommended for people ages 60 and up</a>.</p>
<h2>5. Should some people wait for the updated Novavax vaccine?</h2>
<p>The Moderna and Pfizer vaccines use the more recent vaccine technology based on mRNA, which instructs the body to produce a protein from a small portion of the SARS-CoV-2 virus. The immune system responds by producing antibodies.</p>
<p>In contrast, the Novavax vaccine relies on a more traditional approach to vaccine production, injecting the viral protein directly into the body to stimulate antibody production. So while the two vaccine types use different pathways to trigger antibodies against the virus, the end result is the same.</p>
<p>The CDC has reported <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myocarditis.html">rare cases of myocarditis</a>, which is inflammation of the heart muscle, following vaccination with the Moderna and Pfizer mRNA vaccines. However, <a href="https://www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#myocarditis-pericarditis">the same is true</a> of <a href="https://ir.novavax.com/press-releases/2023-08-22-Novavaxs-Updated-Protein-based-XBB-COVID-Vaccine-Induced-Neutralizing-Responses-Against-Emerging-Subvariants%2C-Including-EG-5-1-and-XBB-1-16-6#">the Novavax vaccine</a>. So all three vaccines carry this very rare risk. </p>
<p>It is noteworthy that myocarditis is <a href="https://www.cdc.gov/vaccines/covid-19/clinical-considerations/myocarditis.html">most frequently seen in adolescent and young adult males</a>. </p>
<p>Although some people may have a preference for the traditional protein-based vaccine by Novavax, those who are at higher risk of catching COVID-19 should not wait for the approval of the Novavax vaccine to get their shot.</p><img src="https://counter.theconversation.com/content/213341/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Prakash Nagarkatti receives funding from the National Institutes of Health and the National Science Foundation.</span></em></p><p class="fine-print"><em><span>Mitzi Nagarkatti receives funding from the National Institutes of Health and National Science Foundation.</span></em></p>Only time and data will tell whether the CDC-recommended reformulated shots can stand their ground against the ever-changing SARS-CoV-2 variants.Prakash Nagarkatti, Professor of Pathology, Microbiology and Immunology, University of South CarolinaMitzi Nagarkatti, Professor of Pathology, Microbiology and Immunology, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124532023-09-12T12:27:46Z2023-09-12T12:27:46ZHow evasive and transmissible is the newest omicron offshoot, BA.2.86, that causes COVID-19? 4 questions answered<figure><img src="https://images.theconversation.com/files/547087/original/file-20230907-27-nxmvcq.jpg?ixlib=rb-1.1.0&rect=0%2C23%2C8000%2C4467&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">BA.2.86 is beginning to spread throughout the United States.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/coronavirus-royalty-free-image/1215392654?phrase=new+covid+variant+BA+2.86&adppopup=true">baranozdemir/E+ via Getty Images</a></span></figcaption></figure><p><em>The latest variant, or sublineage, of SARS-CoV-2 to emerge on the scene, BA.2.86, has public health experts on alert as <a href="https://www.washingtonpost.com/business/2023/09/07/new-covid-eris-variant-what-to-know-about-rising-eg-5-cases/f92bab1a-4d96-11ee-bfca-04e0ac43f9e4_story.html">COVID-19 hospitalizations begin to rise</a> and the new variant makes its way across the globe.</em> </p>
<p><em>The Conversation asked <a href="https://scholar.google.com/citations?user=dqahf8oAAAAJ&hl=en">Suresh V. Kuchipudi</a>, a virologist and infectious disease expert at the University of Pittsburgh School of Public Health, to explain what researchers know about BA.2.86’s ability to dodge immune protection and whether it causes more severe infection than its predecessors.</em></p>
<h2>1. What is BA.2.86 and how is it related to earlier variants?</h2>
<p>BA.2.86, nicknamed Pirola, is a highly mutated new omicron sublineage of SARS-CoV-2 that was first detected in Denmark in July 2023. The World Health Organization announced that, as of Sept. 6, 2023, BA.2.86 <a href="https://www.who.int/publications/m/item/virtual-press-conference-on-global-health-issues-transcript---6-september-2023">has been detected in 11 countries</a>. </p>
<p>A variant is an alternate version of a virus – in this case, the <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html#anchor_1633452601080">SARS-CoV-2 virus that causes COVID-19</a> – that has some mutations or changes in its genetic code, compared with the original. Mutations can alter the behavior of the viruses in various ways, such as how effectively they break into cells and how rapidly they can replicate. </p>
<p>The <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants#">WHO names these variants</a> using Greek alphabet letters, like alpha, delta and omicron. However, another naming system called the PANGO, or pangolin – short for <a href="https://cov-lineages.org/resources/pangolin.html">phylogenetic assignment of named global outbreak lineages</a> – tracks variants and their offshoots by way of a lineage system. </p>
<p>Think of it as a family tree for the virus, which is grouped into different lineages, like branches on a tree. The omicron variant is like a big family, and its known family members – <a href="https://theconversation.com/what-is-the-new-covid-19-variant-ba-2-and-will-it-cause-another-wave-of-infections-in-the-us-179619">BA.2</a>, BA.2.86 and XBB.1.5 – are all branches – or lineages and sublineages – on the same tree.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/kz7FkxIOIT4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Nicknamed Pirola, BA.2.86 has more than 30 distinct mutations compared with its predecessors.</span></figcaption>
</figure>
<h2>2. What is most unique about BA.2.86?</h2>
<p>After the omicron variant showed up in November 2021, it didn’t stay the same for long. It kept changing, and soon we got different sublineages of it, such as BA.2, BA.4 and BA.5. The one that’s been dominant globally for most of 2023, called XBB.1.5, <a href="https://www.who.int/news/item/27-10-2022-tag-ve-statement-on-omicron-sublineages-bq.1-and-xbb">originated from the mixing</a>, or <a href="https://doi.org/10.1016/j.chom.2023.05.003%20two%20separate">recombination, of two separate sublineages</a>.</p>
<p>But what’s interesting is that BA.2.86, the newest sublineage on the scene, seems to have come from the older BA.2 omicron lineage that was dominant in early 2022 and not from the newer omicron offshoots. </p>
<p>A preliminary study reported that BA.2.86 features <a href="https://doi.org/10.1101/2023.09.01.555815">33 distinct spike mutations</a> when compared to its precursor, BA.2. The spike proteins, which form the knobby protrusions coming off the main body of the virus, are like a key that the virus uses to unlock our cells, which is how a new infection begins. </p>
<p>After an infection by one of the variants that cause COVID-19, our bodies create antibodies that target the spike protein to help neutralize the virus and prevent it from infecting cells. So, numerous changes in the spike protein of BA.2.86 could potentially affect how well it evades antibodies as well as the degree of disease severity it causes.</p>
<p>Among the new mutations that BA.2.86 carries, 14 reside within an area of the spike protein called the receptor binding domain, which binds to the receptors on host cells. This suggests that BA.2.86 could have a greater capacity for infecting than its predecessor. </p>
<p>In addition, the new sublineage, BA.2.86, is even more dissimilar when compared to the most recent sublineage, XBB.1.5, with <a href="https://doi.org/10.1101/2023.09.01.555815">35 new mutations in the spike protein</a> – including some unusual mutations – than to its precursor, BA.2. These alterations intrigue infectious disease specialists like me, and we are working to understand how they might affect this new variant’s behavior. </p>
<h2>3. How concerning are the new variant’s mutations?</h2>
<p>We researchers do not yet fully understand what these changes might mean and the degree to which BA.2.86 can get around our protective defenses.</p>
<p>Scientists and <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html">health authorities closely monitor</a> all emerging variants and lineages for changes that can affect how easily the virus is transmitted, what it might mean for vaccine effectiveness and the severity of disease it can cause. While mutations can be cause for concern, it’s important to remember that not all mutations lead to increased danger. </p>
<p>The earlier-mentioned preliminary study found that BA.2.86 <a href="https://doi.org/10.1101/2023.09.01.555815">can escape the protective defenses of</a> antibodies against the recent XBB sublineages. However, in contrast, another new study that has not yet been published found that neutralizing antibody responses against BA.2.86 were <a href="https://doi.org/10.1101/2023.09.04.556272">comparable to or slightly higher</a> against the recent XBB sublineages. Hence further studies are needed to understand BA.2.86’s ability to escape antibody protection.</p>
<p>The emergence of BA.2.86 underscores the need for flexibility in current vaccine strategies to ensure continued effectiveness against these new variants. The newly <a href="https://www.nytimes.com/2023/09/11/health/covid-vaccine-boosters-fda-pfizer-moderna.html">FDA-approved fall 2023 COVID-19 booster shots</a> are formulated to target XBB.1.5, which was dominant in early 2023 when public health officials made the reformulation decisions. The <a href="https://theconversation.com/will-omicron-specific-booster-shots-be-more-effective-at-combating-covid-19-5-questions-answered-189610">2022 booster shot</a> was designed to target both the original strain of SARS-CoV-2 as well as the BA.4 and BA.5 omicron lineages.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/KprEc-ZyFzQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Some Americans are choosing to mask up again.</span></figcaption>
</figure>
<h2>4. What more do researchers hope to learn about it?</h2>
<p>We researchers have much more to learn about BA.2.86’s capacity to evade antibody protection from prior infection or vaccination, its transmissibility and its ability to cause severe disease. It is too early to determine whether the <a href="https://www.cnbc.com/2023/09/06/covid-hospitalizations-spike-with-new-variant-as-us-readies-vaccines.html">late summer rise in hospitalizations</a> is being caused by this new sublineage.</p>
<p>The fact that the new highly mutated SARS-CoV-2 variant traces its origins back to an omicron variant that circulated more than a year ago is a stark reminder of the complex evolutionary pathways that SARS-CoV-2 can undertake as it adapts and changes. It also underscores the critical need for a more comprehensive understanding of the health threats posed by continually emerging SARS-CoV-2 variants. </p>
<p>This is particularly important as there has been a significant reduction in <a href="https://theconversation.com/genomic-surveillance-what-it-is-and-why-we-need-more-of-it-to-track-coronavirus-variants-and-help-end-the-covid-19-pandemic-157540">global SARS-CoV-2 genomic surveillance</a>, which tracks the genetic changes over time and <a href="https://theconversation.com/from-delta-to-omicron-heres-how-scientists-know-which-coronavirus-variants-are-circulating-in-the-us-173971">identifies new versions</a>. Losing this type of monitoring hampers the process of working to understand the origins of novel SARS-CoV-2 variants. This critical information helps scientists and doctors make better decisions to protect public health.</p>
<p>COVID-19 variants continue to stay one step ahead of our efforts at combating them, so it will become increasingly important that the U.S. step up its genomic surveillance efforts and stay committed to working collaboratively with other countries.</p><img src="https://counter.theconversation.com/content/212453/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Suresh V. Kuchipudi receives funding from the National Institutes of Health (NIH), U.S. Department of Agriculture's National Institute of Food and Agriculture (USDA-NIFA) and National Science Foundation (NSF).</span></em></p>Researchers still don’t know how well BA.2.86 will evade immunity or whether it will cause more severe disease than its predecessors.Suresh V. Kuchipudi, Professor and Department Chair of Infectious Diseases and Microbiology, University of PittsburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2120712023-08-31T16:38:27Z2023-08-31T16:38:27ZCOVID-19 vaccine boosters are the best defence: Older adults shouldn’t rely on previous infection for immunity<figure><img src="https://images.theconversation.com/files/545373/original/file-20230829-19-8db363.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C8913%2C5448&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers found a surprising twist in a study of Omicron infection in older adults. The new information highlights the importance of COVID-19 vaccine booster shots.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/covid-19-vaccine-boosters-are-the-best-defence-older-adults-shouldnt-rely-on-previous-infection-for-immunity" width="100%" height="400"></iframe>
<p>Despite researchers’ efforts to understand SARS-CoV-2, the virus continues to hold many secrets. As much as we’ve tried to shoehorn it into our thinking about how respiratory viruses work, it will simply not comply. </p>
<p>Some thought the virus would settle into a strictly <a href="https://www.the-scientist.com/news-opinion/is-covid-19-seasonal-69402">seasonal pattern</a>. It hasn’t. </p>
<p>Some thought we could move to a single annual vaccine every autumn. That was upended by having <a href="https://health-infobase.canada.ca/covid-19/current-situation.html#figure6-header">multiple waves of infection each year</a>, that seem to occur in the late summer. </p>
<p><a href="https://www.publichealthontario.ca/-/media/Documents/nCoV/voc/2023/02/risk-assessment-omicron-sub-lineage-xbb1-xbb15-feb-02.pdf?rev=17a41da58aea4d4989ef90cacfd5348a&sc_lang=en">Some variants</a> we thought would be terrible turned out to be mild, <a href="https://www.publichealthontario.ca/-/media/Documents/nCoV/voc/2022/07/evidence-brief-ba4-ba5-risk-assessment-jul-8.pdf">while others</a> have turned out to be very problematic.</p>
<h2>Surprising study results</h2>
<p>Now we have a new puzzle. </p>
<p>Through the first couple of years of the pandemic before the emergence of the Omicron variant, it was believed the combination of vaccination and prior infection — which is called <a href="https://www.science.org/doi/full/10.1126/science.abj2258">hybrid immunity</a> — provided the highest level of protection against future infections.</p>
<figure class="align-center ">
<img alt="A reddish amorphous blob dotted with small blue particles" src="https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=536&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=536&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545344/original/file-20230829-31730-n00e2v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=536&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A colourized microscopic image of a cell infected with the Omicron strain of SARS-CoV-2 virus. Surprising research findings show that those infected with the BA.1-2 Omicron variant were at increased risk of a second infection with the BA.5 Omicron variant.</span>
<span class="attribution"><span class="source">NIAID</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Our research group has been studying vaccinated older adults in long-term care and retirement homes throughout the pandemic, and our recent findings have jolted us. </p>
<p><a href="https://doi.org/10.1016/j.eclinm.2023.102148">We found that those who had battled the BA.1-2 variant of Omicron in early 2022 had a 30-fold higher risk of contracting the BA.5 variant later in the year</a>. That was exactly the opposite of what we, or anyone, would have predicted. </p>
<p>This new knowledge is critically important, not just to other older adults, but to all of us. </p>
<p>Does this surprising twist apply to the broader population? Possibly, but until we know how infections work to increase susceptibility to reinfection, we can’t know if this susceptibility is specific to older adults. Does it apply to other variants, including the newest ones in circulation? That’s unclear. </p>
<p>What the findings do tell us is that older adults who have had a previous COVID-19 infection shouldn’t rely on that to protect them against reinfection this fall. To protect against severe illness, keeping booster shots up to date is recommended.</p>
<h2>We can’t let our guard down</h2>
<p>We were able to make this discovery because our study participants in long-term care and retirement homes are part of the most frequently tested, highly vaccinated and closely observed group in the entire population. </p>
<p>The <a href="https://www.health.gov.on.ca/en/pro/programs/publichealth/coronavirus/docs/contact_mngmt/management_cases_contacts.pdf">end of frequent PCR testing</a> and documentation of infection for those who are sick (after all, we researchers don’t know if you tested positive on a rapid test) left us without much data about COVID infections and reinfections in the broader population, so these seniors are helping us see things we’d otherwise have missed. </p>
<p>Through them, we’ve realized the virus has evolved in a way that means one infection doesn’t necessarily guarantee immunity from another.</p>
<p>Though we still have so much to learn about many aspects of COVID-19 — including its lingering health effects and the mechanics of its endless mutations — we do know enough to say one thing: we can’t let our guard down. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/long-covid-for-the-1-in-10-patients-who-become-long-haulers-covid-19-has-lasting-effects-173817">Long COVID: For the 1 in 10 patients who become long-haulers, COVID-19 has lasting effects</a>
</strong>
</em>
</p>
<hr>
<p>Among other conclusions, we know that while vaccines mitigate the worst <a href="https://www.mcmasterforum.org/docs/default-source/product-documents/living-evidence-syntheses/covid-19-living-evidence-synthesis-10.16---what-is-the-long-term-effectiveness-of-available-covid-19-vaccines-for-adults.pdf?sfvrsn=874196e5_6">consequences of subsequent COVID infections</a>, the virus is still developing new ways to elude our immune systems.</p>
<h2>Protecting ourselves and our communities</h2>
<p>So, do we still need masks and boosters? Yes. However tiresome they have become, they’re still crucial. This is especially true for our most vulnerable, including <a href="https://www.canada.ca/en/public-health/services/publications/diseases-conditions/people-high-risk-for-severe-illness-covid-19.html">older adults, people with chronic conditions or who are immune compromised</a> and those who work with them. </p>
<figure class="align-center ">
<img alt="An older couple and a teen sitting on a sofa showing vaccination bandages on their upper arms" src="https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545371/original/file-20230829-17-ty0ly1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Masks and boosters are still crucial, especially for our most vulnerable populations, including older adults, people with chronic conditions and those who are immune compromised.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>We know the <a href="https://www.mcmasterforum.org/docs/default-source/product-documents/infographics/les-6.41-infographic.pdf?sfvrsn=910e889d_5">protective value</a> of multiple COVID vaccines <a href="https://www.mcmasterforum.org/docs/default-source/product-documents/infographics/les_10.16-infographic.pdf?sfvrsn=2cc8188e_5">does not accumulate</a> like money in a bank account. It’s the <a href="https://www.mcmasterforum.org/docs/default-source/product-documents/living-evidence-syntheses/covid-19-living-evidence-synthesis-6.41---what-is-the-efficacy-and-effectiveness-of-available-covid-19-vaccines-in-general-and-specifically-for-variants-of-concern.pdf?sfvrsn=6a3ce34c_5">recency of our boosters</a> that will determine our degree of protection.</p>
<p>Though imperfect, timely boosters are still our best shields. It’s time to think of them less like our childhood vaccines, where we expect to be protected for long periods of time, and more like annual flu vaccines where we need to be vaccinated for the strain that is circulating and can only expect that protection to reduce symptomatic infection, last a few months but — importantly — <a href="https://doi.org/10.1093/cid/ciy748">help keep us out of hospital</a>. </p>
<p>We need to remain vigilant and to continue to keep our vaccines up to date, to protect against COVID infections and their threat of debilitating <a href="https://science.gc.ca/site/science/en/office-chief-science-advisor/initiatives-covid-19/post-covid-19-condition-canada-what-we-know-what-we-dont-know-and-framework-action">long-term effects</a> and <a href="https://doi.org/10.1001/jama.2023.5348">even death</a>. </p>
<h2>Protecting ourselves and our communities</h2>
<p>Our participants have been great partners in our work. As a group, and are willing to participate in this research because they are interested in helping others. They helped us discover that hybrid immunity does not always protect older adults from future COVID-19 infection, suggesting that some assumptions about COVID-19 infection risk may need to be revisited, and that we need to study how different variants evade the immune system.</p>
<p>These research partners deserve the thanks of the community for contributing to this important lesson. We can all honour them by heeding that lesson and taking precautions against spreading COVID-19 this fall, including wearing masks and getting a booster shot.</p><img src="https://counter.theconversation.com/content/212071/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dawn ME Bowdish received funding from the COVID-19 Immunity Task Force/Public Health Agency to perform the research described herein. She is a member of the Board of Directors of the Lung Health Foundation. </span></em></p><p class="fine-print"><em><span>Andrew Costa received funding from the COVID-19 Immunity Task Force/Public Health Agency to perform the research described herein.</span></em></p>We still have much to learn about many aspects of COVID-19 — including its lingering health effects and the mechanics of its endless mutations — but we do know one thing: we can’t let our guard down.Dawn ME Bowdish, Canada Research Chair in Aging & Immunity, McMaster UniversityAndrew Costa, Associate Professor | Schlegel Chair in Clinical Epidemiology & Aging, McMaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2067222023-05-31T21:00:47Z2023-05-31T21:00:47ZThe first line of vaccines was highly effective at restricting COVID-19’s damage<figure><img src="https://images.theconversation.com/files/529180/original/file-20230530-23-yawj7u.jpg?ixlib=rb-1.1.0&rect=76%2C66%2C5471%2C3793&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">More than 70 per cent of the world’s population has received at least one COVID-19 vaccination.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/the-first-line-of-vaccines-was-highly-effective-at-restricting-covid-19-s-damage" width="100%" height="400"></iframe>
<p>After more than three years of COVID-19, the <a href="https://covid19.who.int/">World Health Organization</a> (WHO) reports that over 763 million infections, and nearly seven million deaths, have been attributed to SARS-CoV-2. </p>
<p>COVID-19 vaccination was deemed crucial to prevent the continued spread of the disease, protect those infected from experiencing severe effects, counter the rise of new variants, and ultimately end the pandemic. </p>
<p>The WHO has <a href="https://theconversation.com/learning-from-covid-19-the-global-health-emergency-has-ended-heres-what-is-needed-to-prepare-for-the-next-one-205282">lifted the Public Health Emergency of International Concern</a>, but ending the ongoing threat of COVID-19 still depends on vaccination and other protective behaviours. Understanding the effectiveness of vaccines remains crucial. </p>
<h2>Primary doses and boosters</h2>
<p>Today, more than <a href="https://www.nytimes.com/interactive/2021/world/covid-vaccinations-tracker.html">5.5 billion</a> people (72.3 per cent of the world’s population) have received at least one dose of a COVID-19 vaccine. A total of <a href="https://www.nytimes.com/interactive/2021/world/covid-vaccinations-tracker.html">5.09 billion</a> people have completed a primary COVID-19 vaccination series (i.e., two doses of a two-dose vaccine or one dose of a one-dose vaccine).</p>
<p>At the end of 2021, several countries began offering booster doses in response to research indicating that the effectiveness of the vaccines may diminish over time, especially against the Omicron variant, which emerged in late 2021, and has become <a href="https://covid.cdc.gov/covid-data-tracker/#variant-summary">the dominant circulating variant</a>.</p>
<p>With this in mind, we sought to answer two questions. First, how well does the primary series of COVID-19 vaccines protect people (against infections, hospitalizations and deaths) four months or more after completing vaccination? Second, how well does the first booster dose protect people three months or more after receiving it? </p>
<p>Answering these questions will provide invaluable information for policymakers to make evidence-based decisions, such as the timing of administering COVID-19 vaccine booster doses.</p>
<p>To answer these questions we sought to identify all studies that:</p>
<ol>
<li><p>Compared people who were vaccinated (either with the primary series or a booster) to people who were unvaccinated;</p></li>
<li><p>Followed people for at least 112 days after a primary series, or 84 days after a booster dose, and;</p></li>
<li><p>Looked at who got infected, was hospitalized or died due to COVID-19.</p></li>
</ol>
<p>In total, we identified 68 studies that met these criteria, representing 23 countries. We then combined all the data to better understand how the vaccines’ protection changes over time. The results were published in <a href="https://doi.org/10.1016/S2213-2600(23)00015-2"><em>Lancet Respiratory Medicine</em></a>.</p>
<h2>Protection against COVID-19, in general</h2>
<p>The <a href="https://www.who.int/news-room/feature-stories/detail/vaccine-efficacy-effectiveness-and-protection">WHO</a> has set standards to define whether a vaccine offers adequate protection. Specifically, vaccines should show at least 70 per cent protection against infections and 90 per cent protection against hospitalizations and deaths.</p>
<p>We found that the primary series offered excellent protection against hospitalizations and deaths in the short term, showing over 90 per cent protection against both outcomes within 42 days after vaccination. This protection waned over time, going below the WHO recommendation, but stayed relatively high, at around 80 per cent against hospitalizations at eight months post-vaccination, and around 85 per cent against deaths at six months post-vaccination. </p>
<p>The primary series also offered good protection against infections in the short term (over 80 per cent within the first 42 days), but that protection fell to around 60 per cent after four months, and 50 per cent after nine months.</p>
<p>The initial protection of a booster dose was around 70 per cent against infections and 90 per cent against hospitalizations within the first month after vaccinations. Protection then fell to around 45 per cent against infections and to around 70 per cent against hospitalizations after four months had passed. Too little data was available to track the long-term effects against deaths.</p>
<p>Overall, the vaccines work at preventing infections, hospitalizations and deaths related to COVID-19, but their effectiveness does decline over time, particularly against infections. Boosters restore protection lost, but may need additional boosting over time.</p>
<h2>Protection against the Omicron variant</h2>
<p>Vaccines were generally less effective against the Omicron variant, which <a href="https://www.who.int/news-room/feature-stories/detail/one-year-since-the-emergence-of-omicron">emerged in fall 2021</a>, about a year after <a href="https://www.canada.ca/en/health-canada/news/2020/12/health-canada-authorizes-first-covid-19-vaccine0.html">COVID-19 vaccines were introduced</a>. </p>
<p>Within 42 days after vaccination with the original COVID-19 vaccine formulations, the primary series only reached around 60 per cent protection against Omicron-based infections, and this dropped to around 30 per cent after five months. </p>
<p>The primary series’ protection against hospitalization for Omicron infections reached around 70 per cent within the first 42 days, but also dropped over time, reaching closer to 50 per cent after six months. None of these reached the levels recommended by the WHO.</p>
<p>The boosters did fare better in protecting against Omicron. Within the first 28 days after the booster, protection hovered close to the 70 per cent threshold against infections and 90 per cent threshold against hospitalizations recommended by the WHO. </p>
<p>For context, if individuals delayed the administration of the booster by six months after completing the primary series, their protection levels would be around 20 per cent against Omicron infections and around 50 per cent against hospitalizations right before receiving the booster. </p>
<p>Yet, booster protection also waned over time, falling to about 40 per cent against Omicron infections and 70 per cent against hospitalizations after four months post-booster. Too little data was available to comment on long-term effects against deaths.</p>
<figure class="align-center ">
<img alt="Syringes lined up in front of two vials of vaccine" src="https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529176/original/file-20230530-29-6s96j1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pfizer, left, and Moderna bivalent COVID-19 vaccines were introduced in fall 2022.</span>
<span class="attribution"><span class="source">(AP Photo/Steve Helber)</span></span>
</figcaption>
</figure>
<p>With Omicron, boosters are particularly needed to maintain adequate protection, but this protection also needs additional boosting as it wanes over time. </p>
<p>New formulations of mRNA COVID-19 vaccines that target the Omicron variant were introduced in fall 2022, <a href="https://www.canada.ca/content/dam/phac-aspc/documents/services/immunization/national-advisory-committee-on-immunization-naci/recommendations-use-bivalent-Omicron-containing-mrna-covid-19-vaccines.pdf">and are recommended for booster shots by Canada’s National Advisory Commission on Immunization</a>. The <a href="https://www.canada.ca/content/dam/phac-aspc/documents/services/publications/vaccines-immunization/national-advisory-committee-immunization-summary-guidance-additional-covid-19-booster-dose-spring-2023-individuals-high-risk-severe-illness-due-covid-19-march-3-2023/summary.pdf">Public Health Agency of Canada recommended in March 2023</a> that people at high risk of severe COVID-19 get an additional booster shot.</p>
<p>In May, <a href="https://covid.cdc.gov/covid-data-tracker/#variant-summary">the WHO recommended</a> that new formulations of COVID-19 vaccines should target Omicron XBB variants, which are the dominant variants currently circulating. </p>
<h2>Behaviour-based prevention measures remain necessary</h2>
<p>While vaccines provide reasonable protection against COVID-19 infections, hospitalizations and deaths, their effectiveness is imperfect and wanes over time, particularly against the now-dominant Omicron variant for people vaccinated with the original vaccines. </p>
<p>Notably, waning is especially pronounced against infections. This means that although being vaccinated is likely to protect most people against becoming severely ill, vaccinated people are still at risk of catching the virus and transmitting it to others — some of whom will be at higher risk of severe complications from the disease.</p>
<p>That means <a href="https://www.mcmasterforum.org/networks/covid-end/covid-end-evidence-syntheses/scan-evidence-products">measures</a> like wearing a mask, washing one’s hands, and staying at home when sick remain essential complements to vaccination. Contrary to vaccines, these measures do not decline in effectiveness over time and are particularly well suited to protect people against infections. </p>
<p>Eliminating the threat of new COVID-19 infections will continue to rely heavily on a combination of vaccination and behaviours, whereas new vaccine doses will continue to protect those who are infected from severe complications like hospitalizations and deaths.</p><img src="https://counter.theconversation.com/content/206722/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nana Wu receives funding from the Canadian Institutes of Health Research (CIHR).</span></em></p><p class="fine-print"><em><span>Keven Joyal-Desmarais receives funding from the Fonds de recherche du Québec (FRQ) and the Canadian Institutes of Health Research (CIHR).</span></em></p><p class="fine-print"><em><span>Simon Bacon receives funding from Fonds de recherche du Québec (FRQ), Canadian Institutes of Health Research (CIHR), Canadian Foundation for Innovation (CFI), Public Health Agency of Canada (PHAC), Weston Family Foundation, Canadian Cancer Society (CCS), Heart and Stroke Foundation of Canada (HSFC), Quebec Ministère de l’économie et de l’innovation (MEI), Canadian Partnership Against Cancer (CPAC), Canadian Statistical Sciences Institute (CANSSI), The Auger Foundation, Concordia University, CIUSSS-NIM. </span></em></p>New analysis answers questions about the ongoing effectiveness of COVID vaccines: How well they protect against infection, hospitalization and death months after initial doses or after a booster shot.Nana Wu, Postdoctoral Research Fellow, Department of Health, Kinesiology, and Applied Physiology, Concordia UniversityKeven Joyal-Desmarais, Postdoctoral Fellow, Department of Health, Kinesiology, and Applied Physiology, Concordia UniversitySimon Bacon, Professor of Behavioural Medicine, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2057222023-05-17T12:41:07Z2023-05-17T12:41:07ZPivotal points in the COVID-19 pandemic – 5 essential reads<figure><img src="https://images.theconversation.com/files/526612/original/file-20230516-37571-gp5zr6.jpg?ixlib=rb-1.1.0&rect=43%2C28%2C9547%2C5161&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">SARS-CoV-2, the virus that causes COVID-19, has evolved over time into multiple variants and sublineages. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/coronavirus-royalty-free-image/1366654397?phrase=covid+virus&adppopup=true">loops7 / E+ via Getty Images</a></span></figcaption></figure><p>Experts have made it clear that the <a href="https://theconversation.com/what-does-ending-the-emergency-status-of-the-covid-19-pandemic-in-the-us-mean-in-practice-4-questions-answered-205165">end of the COVID-19 national emergency</a>, which was lifted on May 11, 2023, <a href="https://www.statnews.com/2023/05/10/public-health-emergency-ashish-jha/">does not mean an end to the pandemic</a>. But this shift signals a remarkable turning point in a pandemic that is well into its fourth year – something that few could have imagined when the U.S. national emergency went into effect in March 2020. </p>
<p>Likewise, the World Health Organization’s announcement on May 5 that it was <a href="https://www.statnews.com/2023/05/05/who-declares-end-to-covid-global-health-emergency/">ending the COVID-19 public health emergency of international concern</a> that had been in place since January 2020 is indicative that the pandemic has entered a new chapter. </p>
<p>It’s daunting to look back at our coverage and narrow it down to just a handful of standout stories amid all the twists and turns of the pandemic. But here are five stories from The Conversation’s archives that resonated with us, written by scholars who helped to illuminate complex issues at pivotal moments in the pandemic.</p>
<h2>1. A whole new vocabulary</h2>
<p>It’s a little hard to remember the days when words like pandemic, endemic diseases, mRNA, variant and spike proteins were not a part of our vernacular or everyday conversations. But I vividly recall the day that the COVID-19 pandemic was declared and a friend asked me “What exactly is a pandemic?” It turns out a lot of people were asking that question and wondering about the difference between an outbreak of an infectious disease, an epidemic and a pandemic.</p>
<p><a href="https://public-health.tamu.edu/directory/fischer.html">Rebecca S.B. Fischer</a>, an assistant professor of epidemiology at Texas A&M University, <a href="https://theconversation.com/whats-the-difference-between-pandemic-epidemic-and-outbreak-133048">put it in straightforward terms</a>: An outbreak is a small but unusual increase in the expected number of cases of a given disease, while the term epidemic is used when an infectious disease outbreak is getting bigger and spreading over a broader geographic area. A pandemic, on the other hand, is used when a disease is “international and out of control.”</p>
<p>She went on to say that some epidemiologists reserve the term pandemic for when a disease is being sustained in newly affected regions through local transmission – a good characterization of the state of COVID-19 in March 2020.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whats-the-difference-between-pandemic-epidemic-and-outbreak-133048">What's the difference between pandemic, epidemic and outbreak?</a>
</strong>
</em>
</p>
<hr>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/nclAnJXdgqs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Epidemic, pandemic and endemic viruses explained.</span></figcaption>
</figure>
<h2>2. Comparisons to the 1918 flu ran rife</h2>
<p>From the earliest days of the COVID-19 pandemic, it was impossible to miss the haunting similarities between it and the 1918 flu pandemic, which led to at least 50 million deaths worldwide between 1918 and 1920. Health care experts and the media made frequent comparisons between the two, pointing to similarities in attitudes about mask-wearing and school closures as well as in the patterns of disease waves, spikes and surges.</p>
<p>But while the two once-in-a-century events have shared plenty of likenesses, the comparison also sometimes <a href="https://theconversation.com/compare-the-flu-pandemic-of-1918-and-covid-19-with-caution-the-past-is-not-a-prediction-138895">led to public misunderstandings about how the COVID-19 pandemic could play out</a>, wrote historian <a href="https://www.history.pitt.edu/people/mari-webel">Mari Webel</a> and pediatric infectious disease specialist <a href="https://www.pediatrics.pitt.edu/people/megan-culler-freeman-md-phd">Megan Culler Freeman</a>, both from the University of Pittsburgh. They explain that key differences in the sociopolitical context of the 1918 flu period, as well as marked differences between the virology behind the two diseases, set the 1918 flu and COVID-19 on different paths.</p>
<p>“People seek answers from the experiences of influenza in 1918-19 for a fundamental reason: It ended.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/compare-the-flu-pandemic-of-1918-and-covid-19-with-caution-the-past-is-not-a-prediction-138895">Compare the flu pandemic of 1918 and COVID-19 with caution – the past is not a prediction</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two men wearing and advocating the use of flu masks in Paris with a crowd of people behind them." src="https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526295/original/file-20230515-19800-9b9897.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">French men in 1919 Paris holding signs urging others to wear masks and to fight the flu. Much like in the COVID-19 era, wearing masks to protect against the deadly influenza was embraced by some, while others resisted and refused.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/two-men-wearing-and-advocating-the-use-of-flu-masks-in-news-photo/3333532">Topical Press Agency / Hulton Archive via Getty Images</a></span>
</figcaption>
</figure>
<h2>3. How and when pandemics end</h2>
<p>In late 2020, people were naturally wondering when and how the COVID-19 pandemic would end, and how we would know it was over.</p>
<p><a href="https://sasn.rutgers.edu/about-us/faculty-staff/nukhet-varlik">Nükhet Varlik</a>, a historian from Rutgers University who studies disease, medicine and public health, wrote an astute piece in October 2020 about the difficulties of <a href="https://theconversation.com/how-do-pandemics-end-history-suggests-diseases-fade-but-are-almost-never-truly-gone-146066">predicting how the pandemic might play out</a>. She presciently noted that “whether bacterial, viral or parasitic, virtually every disease pathogen that has affected people over the last several thousand years is still with us, because it is nearly impossible to fully eradicate them.” These include diseases like tuberculosis, leprosy, measles and plague.</p>
<p>“Hopefully COVID-19 will not persist for millennia,” Varlik wrote. But she went on to say that politics are crucial, noting how when vaccination programs are weakened, infections can “come roaring back.”</p>
<p>“Given such historical and contemporary precedents, humanity can only hope that the coronavirus that causes COVID-19 will prove to be a tractable and eradicable pathogen. But the history of pandemics teaches us to expect otherwise.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-pandemics-end-history-suggests-diseases-fade-but-are-almost-never-truly-gone-146066">How do pandemics end? History suggests diseases fade but are almost never truly gone</a>
</strong>
</em>
</p>
<hr>
<h2>4. The midway point</h2>
<p>The summer of 2021 felt like a particularly grueling moment in time – when excitement and optimism over the launch of the first vaccines to protect against COVID-19 had given way to despair over the stronghold of vaccine resistance and general exhaustion with all things COVID. And then came the delta variant. </p>
<p>Epidemiologist <a href="https://scholar.google.com/citations?user=t3nqdNQAAAAJ&hl=en">Katelyn Jetelina</a>, formerly from the University of Texas Health Science Center at Houston, captured <a href="https://theconversation.com/18-months-of-the-covid-19-pandemic-a-retrospective-in-7-charts-166881">18 months of the COVID-19 pandemic in a series of seven retrospective charts</a> that put all of the high and low points into stark relief. “The race between vaccination and variant spread was upon us,” Jetelina wrote. “The fight was far from over.” </p>
<p>The same may still be true today.</p>
<p><iframe id="zCZWb" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/zCZWb/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/18-months-of-the-covid-19-pandemic-a-retrospective-in-7-charts-166881">18 months of the COVID-19 pandemic – a retrospective in 7 charts</a>
</strong>
</em>
</p>
<hr>
<h2>5. How omicron altered the course of the pandemic</h2>
<p>When the omicron variant arrived on the scene in late 2021 and spread globally in early 2022, it soon became clear that it could bring about a shift in the pandemic. With its ability to spread easily and to also cause milder disease than prior variants, omicron had the potential to act as a natural vaccine of sorts – producing widespread immunity with the help of the existing COVID-19 vaccines.</p>
<p>But the omicron variant had plenty of surprises in store. For one, it gave rise to a family of variants and sublineages that to this day are keeping researchers guessing, with the latest omicron subvariant, XBB.1.16, gaining ground across the U.S. and worldwide as of mid-May 2023.</p>
<p>In January 2022, immunology researchers <a href="https://sc.edu/study/colleges_schools/medicine/about_the_school/faculty-staff/nagarkatti_prakash.php">Prakash Nagarkatti</a> and <a href="https://sc.edu/study/colleges_schools/medicine/about_the_school/faculty-staff/nagarkatti_mitzi.php">Mitzi Nagarkatti</a>, from the University of South Carolina, <a href="https://theconversation.com/is-the-omicron-variant-mother-natures-way-of-vaccinating-the-masses-and-curbing-the-pandemic-175496">explained how the immune system responds to infections</a> and how it remembers those threats through “immunological memory.” </p>
<p>This left room for hope, they wrote, that “when new variants of SARS-CoV-2 inevitably arise, omicron will have left the population better equipped to fight them. So the COVID-19 vaccines combined with the omicron variant could feasibly move the world to a new stage in the pandemic – one where the virus doesn’t dominate our lives and where hospitalization and death are far less common.” </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-the-omicron-variant-mother-natures-way-of-vaccinating-the-masses-and-curbing-the-pandemic-175496">Is the omicron variant Mother Nature’s way of vaccinating the masses and curbing the pandemic?</a>
</strong>
</em>
</p>
<hr>
<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/205722/count.gif" alt="The Conversation" width="1" height="1" />
With the emergency phase of the COVID-19 pandemic in the rearview mirror, at least for now, we look back on a handful of stories that provided sharp insights at key moments in the pandemic.Amanda Mascarelli, Senior Health and Medicine EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1978782023-01-25T13:25:09Z2023-01-25T13:25:09ZEven bivalent updated COVID-19 boosters struggle to prevent omicron subvariant transmission – an immunologist discusses why new approaches are necessary<figure><img src="https://images.theconversation.com/files/506017/original/file-20230124-17-uye0hb.jpg?ixlib=rb-1.1.0&rect=61%2C51%2C6816%2C3434&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The FDA is proposing an annual shot against COVID-19, signaling that a new approach is needed.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/antibodies-background-royalty-free-image/1358868801?phrase=antibodies&adppopup=true">wildpixel/iStock via Getty Images Plus</a></span></figcaption></figure><p>By almost any measure, the vaccination campaign against SARS-CoV-2, the virus that causes COVID-19, has been <a href="https://www.unicef.org/coronavirus/the-covid-19-vaccine-success-stories">a global success</a>. </p>
<p>As of January 2023, more than <a href="https://www.bloomberg.com/graphics/covid-vaccine-tracker-global-distribution/">12 billion</a> vaccines against SARS-CoV-2 have been administered in an effort that has saved countless lives – more than <a href="https://doi.org/10.1016/S1473-3099(22)00320-6">14 million</a> in the first year of vaccine availability alone. With a <a href="https://doi.org/10.1056/NEJMoa2034577">95% efficacy</a> in the prevention of severe infection and death, and better safety profiles than similar <a href="https://doi.org/10.1001/jama.294.21.2734">historically effective vaccines</a>, the biomedical community hoped that a combination of vaccination and natural immunity might bring the pandemic to a relatively quick end.</p>
<p>But the emergence of new viral variants, <a href="https://theconversation.com/will-omicron-the-new-coronavirus-variant-of-concern-be-more-contagious-than-delta-a-virus-evolution-expert-explains-what-researchers-know-and-what-they-dont-169020">particularly omicron</a> and its <a href="https://theconversation.com/how-the-omicron-subvariant-ba-5-became-a-master-of-disguise-and-what-it-means-for-the-current-covid-19-surge-187132">array of subvariants</a>, upended those expectations. The latest omicron strain, XBB.1.5. – dubbed “Kraken”, after a mythical sea creature – has rapidly become the dominant subvariant in the U.S. The World Health Organization is calling it <a href="https://www.washingtonpost.com/health/2023/01/05/new-omicron-variant-xbb15-covid-who/">the most contagious strain so far</a>, with its success almost certainly attributable to an ability to dodge immunity from previous vaccines or infections.</p>
<p>The effort to get ahead of these ever-changing variants is also in part what has led the Food and Drug Administration to <a href="https://www.statnews.com/2023/01/23/fda-scientists-propose-an-annual-covid-shot-matched-to-current-strains/?utm_campaign=daily">reconsider its approach</a> to COVID-19 vaccination. On Jan. 23, 2023, the agency proposed that current guidelines for a series of shots followed by a booster be replaced by an annual COVID-19 vaccine that is updated each year to combat current strains. The proposal is set to be reviewed by the FDA’s science advisory committee on Jan. 26.</p>
<h2>Limitations of current mRNA vaccination strategies</h2>
<p>Unfortunately, the new bivalent shots, which include components from both the original SARS-CoV-2 strain as well as a recent omicron variant, have <a href="https://doi.org/10.1056/NEJMp2215780">not performed as well</a> as some scientists had hoped. Although there is no question that the updated jabs are capable of <a href="https://doi.org/10.1056/NEJMc2214293">boosting antibody levels</a> against SARS-CoV-2 and <a href="http://dx.doi.org/10.2139/ssrn.4314067">helping to prevent severe illness and hospitalization</a>, <a href="https://doi.org/10.1101/2022.10.22.513349">several</a> <a href="https://doi.org/10.1101/2022.10.24.513619">studies</a> have suggested that they are not necessarily more capable of preventing omicron infections than their predecessors.</p>
<p>As <a href="https://scholar.google.com/citations?user=-oDHlFYAAAAJ&hl=en">an immunologist</a> who studies how the immune system <a href="https://doi.org/10.1016/j.celrep.2018.09.029">selects which antibodies to produce</a> and <a href="https://doi.org/10.1038/s41586-022-05273-0">immune responses to COVID-19</a>, these new results are disappointing. But they are not entirely unexpected. </p>
<p>When COVID-19 vaccines were being rolled out in early 2021, immunologists began having <a href="https://theconversation.com/immune-interference-why-even-updated-vaccines-could-struggle-to-keep-up-with-emerging-coronavirus-strains-156465">public discussions</a> about the potential obstacles to rapidly generating updated vaccines to emerging viral strains. At the time, there was no hard data. But researchers have known for a <a href="https://www.jstor.org/stable/985534">very long time</a> that immunological memory, the very thing that offers continued protection against a virus long after vaccination, can sometimes negatively interfere with the development of slightly <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2138235/pdf/331.pdf">updated immune responses</a>. </p>
<p>The failure of these new bivalent vaccines in widely preventing omicron infections suggests that our current approach is simply not sufficient to interrupt the viral transmission cycle driving the COVID-19 pandemic. In my view, it’s clear that innovative vaccine designs capable of producing a broader immunity are badly needed. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/mlQ-B3UMBrY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The latest COVID-19 subvariant, XBB.1.5, accounts for a large portion of new cases.</span></figcaption>
</figure>
<h2>Vaccines are designed to generate immune memory</h2>
<p>In simplest terms, vaccines are a way to give your immune system a sneak peek at a pathogen. <a href="https://www.vaccines.gov/basics/types">There are several different ways to do this</a>. One way is to inject inactivated versions of a virus, as has been <a href="https://www.vaccines.gov/diseases/polio">done with polio</a>. Another is to use noninfectious viral components, such as the proteins used for <a href="https://www.cdc.gov/flu/prevent/different-flu-vaccines.htm">flu vaccines</a>. </p>
<p>And most recently, scientists have found ways to deliver mRNA <a href="https://theconversation.com/what-happens-when-the-covid-19-vaccines-enter-the-body-a-road-map-for-kids-and-grown-ups-164624">“instructions” that tell your body</a> how to make those noninfectious viral components. This is the approach used with the <a href="https://www.nytimes.com/interactive/2020/health/moderna-covid-19-vaccine.html">Moderna and Pfizer vaccines</a> targeted against COVID-19.</p>
<p>The mRNA-based vaccines all train your immune system to identify and respond against critical components of a potential invader. An important part of that response is to get your body to produce antibodies that will hopefully prevent future infections, helping to break the cycle of person-to-person transmission. </p>
<p>In a successful response, the immune system will not only produce antibodies that are specific to the pathogen, but will also remember how to make them in case you encounter that same pathogen again in the future.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Vials and syringes containing COVID-19 vaccine are displayed on a tray." src="https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506020/original/file-20230124-11-xb1ovk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The existing approach to COVID-19 vaccines has proved effective at preventing serious illness and death, but it has not prevented infections as well as scientists had hoped.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/vials-with-the-covid-19-vaccine-and-syringes-are-royalty-free-image/1303457369?phrase=immune%20system%20concept&adppopup=true">Morsa Images/DigitalVision via Getty Images</a></span>
</figcaption>
</figure>
<h2>The specter of ‘original antigenic sin’</h2>
<p>But what happens when the virus evolves and that memory becomes obsolete?</p>
<p>Immunologists have wondered this <a href="https://theconversation.com/immune-interference-why-even-updated-vaccines-could-struggle-to-keep-up-with-emerging-coronavirus-strains-156465">since the initial COVID-19 vaccine rollout</a>. Recently, it has found new relevance in light of the <a href="https://www.statnews.com/2023/01/23/fda-scientists-propose-an-annual-covid-shot-matched-to-current-strains/?utm_campaign=daily">FDA’s proposal</a> for an updated annual COVID-19 shot. </p>
<p>While it is possible that immune responses to updated vaccines will <a href="https://doi.org/10.1016/j.it.2022.02.009">simply replace the old ones</a>, that has not been true for influenza. With flu, researchers have learned that preexisting immunity to one strain <a href="https://doi.org/10.4049/jimmunol.0900398">can actively inhibit</a> the ability to respond well against another.</p>
<p>Put in everyday language, think of a virus as a car trying to run you over. You might produce one kind of antibody against the hood, one against the bumper and one against the hubcaps that prevents the wheels from turning. You have produced three kinds of antibodies specific to the car, but it turns out that only the hubcap antibodies effectively slow it down.</p>
<p>Now the car mutates, like SARS-CoV-2 has. It changes the shape of the hubcaps or it removes them altogether. Your immune system still recognizes the car, but not the hubcaps. The system doesn’t know that the hubcap was the only effective target, so it ignores the hubcaps and ramps up its attack on the hood and bumper. </p>
<p>In ignoring the new hubcap response, the immune system’s memory of the original car is not only obsolete, but it is also actively interfering with the response necessary to target the new car’s wheels. This is what immunologists call “<a href="https://doi.org/10.4049/jimmunol.1801149">original antigenic sin</a>” – ineffective immune memory that hampers desired responses to new pathogen strains.</p>
<p>This sort of interference has been extremely difficult to quantify and study in humans, although it may become easier with the <a href="https://www.washingtonpost.com/health/2023/01/23/covid-vaccine-once-a-year/">FDA’s proposal</a>. A once-yearly approach to COVID-19 vaccination opens the door for more straightforward studies on how memory to each vaccine influences the next.</p>
<h2>Multi-strain vaccinations offer hope</h2>
<p>Simultaneously, <a href="https://www.niaidcivics.org/">significant efforts</a> are being made to prioritize the pursuit of a single-shot or “universal” vaccine. One approach has been to take advantage of emerging research showing that if your immune system is presented with multiple versions of the same pathogen, it will tend to <a href="https://doi.org/10.1016/j.celrep.2018.09.029">choose targets that are shared between them</a>. </p>
<p>Presented with a Model T, Ford F-150 and electric Mustang all at once, your immune system will often choose to ignore differences like the hubcaps in favor of similarities like the shape and rubber on the tires. Not only would this interfere with the function of all three vehicles, but it could theoretically interfere with most road-based vehicles – or viral threats such as variants.</p>
<p>Researchers have begun making rapid headway using this approach with the development of <a href="https://doi.org/10.1038/s41591-020-1118-7">complex multi-strain flu vaccines</a> that are performing well in early clinical trials. New studies focused on SARS-CoV-2 <a href="https://doi.org/10.1016/j.ebiom.2022.104341">hope to do the same</a>. Persistent pathogens including <a href="https://doi.org/10.1186/s12985-017-0918-y">influenza</a> and <a href="https://doi.org/10.1038/ni.3158">HIV</a> all suffer from versions of the same antibody-targeting issues. It is possible that this pandemic may serve as a crucible of innovation that leads to the next generation of infectious disease prevention.</p>
<p><em>This is an updated version of an article <a href="https://theconversation.com/immune-interference-why-even-updated-vaccines-could-struggle-to-keep-up-with-emerging-coronavirus-strains-156465">originally published on March 8, 2021</a>.</em></p><img src="https://counter.theconversation.com/content/197878/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Woodruff does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The new bivalent boosters against COVID-19 have failed to halt omicron infections. However, new technologies are being developed that pave a way forward.Matthew Woodruff, Instructor of Human Immunology, Emory UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1976022023-01-16T23:55:32Z2023-01-16T23:55:32ZFAQ on COVID-19 subvariant XBB.1.5: What is it? Where is it prevalent? How does it differ from Omicron? Does it cause serious illness? How can I protect myself? Why is it nicknamed ‘Kraken’?<figure><img src="https://images.theconversation.com/files/504746/original/file-20230116-14-fkca7k.jpg?ixlib=rb-1.1.0&rect=281%2C32%2C6216%2C3757&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">XBB.1.5 is rapidly spreading across the globe and will likely become the next dominant COVID-19 subvariant.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/faq-on-covid-19-subvariant-xbb-1-5--what-is-it-where-is-it-prevalent-how-does-it-differ-from-omicron-does-it-cause-serious-illness-how-can-i-protect-myself-why-is-it-nicknamed--kraken-" width="100%" height="400"></iframe>
<p>Despite intensive public health efforts to grind the COVID-19 pandemic to a halt, the recent emergence of the highly transmissible, extensively drug-resistant and profoundly immune system-evading XBB.1.5 SARS-CoV-2 subvariant is putting the global community on edge.</p>
<h2>What is XBB.1.5?</h2>
<p>In the naming convention for SARS-CoV-2 lineages, the <a href="https://virological.org/t/pango-lineage-nomenclature-provisional-rules-for-naming-recombinant-lineages/657">prefix “X” denotes a pedigree that arose through genetic recombination</a> between two or more subvariants. </p>
<p>The XBB lineage emerged following natural <a href="https://www.who.int/news/item/27-10-2022-tag-ve-statement-on-omicron-sublineages-bq.1-and-xbb">co-infection of a human host with two Omicron subvariants, namely BA.2.10.1 and BA.2.75</a>. It was <a href="https://doi.org/10.1007/s12291-022-01109-w">first identified by public health authorities in India during summer 2022</a>. XBB.1.5 is a direct descendent, or more accurately, the “fifth grandchild” of the original XBB subvariant.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of the genetic lineage of a COVID-19 subvariant" src="https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=355&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=355&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=355&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=446&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=446&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504369/original/file-20230113-24-li24wl.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=446&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Genetic lineage of COVID-19 subvariant XBB.1.5.</span>
<span class="attribution"><span class="source">(Sameer Elsayed)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>How does XBB.1.5 differ from Omicron?</h2>
<p>XBB.1.5 is one of many Omicron subvariants of concern that have appeared on the global pandemic scene since the onset of the <a href="https://www.who.int/news-room/feature-stories/detail/one-year-since-the-emergence-of-omicron">first Omicron wave in November 2021</a>. In contrast to other descendants of the original Omicron variant (known as B.1.1.529), XBB.1.5 is a mosaic subvariant that <a href="https://doi.org/10.1007/s12291-022-01109-w">traces its roots to two Omicron subvariant lineages</a>. </p>
<p>XBB.1.5 is arguably the most genetically rich and <a href="https://www.scientificamerican.com/article/why-covids-xbb-1-5-kraken-variant-is-so-contagious/">most transmissible</a> SARS-CoV-2 Omicron subvariant yet. </p>
<h2>Where is XBB.1.5 prevalent?</h2>
<p><a href="https://www.who.int/docs/default-source/coronaviruse/11jan2023_xbb15_rapid_risk_assessment.pdf">According to the World Health Organization</a>, XBB.1.5 is circulating in at least 38 countries, with the highest prevalence in the United States, where it <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">accounts for approximately 43 per cent of COVID-19 cases nationwide</a>. Within the U.S., there is wide geographic variation in the proportion of cases caused by XBB.1.5, ranging from <a href="https://www.beckershospitalreview.com/public-health/xbb-1-5-prevalence-by-region.html">seven per cent in the Midwest to over 70 per cent in New England</a>. </p>
<p>XBB.1.5 has also been officially reported by governmental agencies in <a href="https://www.health.nsw.gov.au/Infectious/covid-19/Documents/weekly-covid-overview-20230107.pdf">Australia</a>, <a href="https://www.publichealthontario.ca/-/media/documents/ncov/epi/covid-19-sars-cov2-whole-genome-sequencing-epi-summary.pdf">Canada</a>, the <a href="https://www.ecdc.europa.eu/en/news-events/update-sars-cov-2-variants-ecdc-assessment-xbb15-sub-lineage">European Union</a>, <a href="https://www3.nhk.or.jp/nhkworld/en/news/20230112_36/">Japan</a>, <a href="https://www.kuna.net.kw/ArticleDetails.aspx?id=3077268&Language=en">Kuwait</a>, <a href="https://tass.com/world/1561313">Russia</a>, <a href="https://cov-spectrum.org/explore/Singapore/AllSamples/Past6M/variants?nextcladePangoLineage=xbb.1.5*&">Singapore</a>, <a href="https://www.nicd.ac.za/covid-19-update-xbb-1-5-variant/">South Africa</a> and the <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1128554/variant-technical-briefing-49-11-january-2023.pdf">United Kingdom</a>. <a href="https://outbreak.info/situation-reports?xmin=2022-07-13&xmax=2023-01-13&loc&pango=XBB.1&selected">Real-time surveillance data</a> reveals that XBB.1.5 is rapidly spreading across the globe and will likely become the next dominant subvariant.</p>
<p>XBB.1.5 has also been detected in municipal wastewater systems in the <a href="https://health.hawaii.gov/coronavirusdisease2019/files/2023/01/Wastewater-Report-01-03-23.pdf">United States</a>, <a href="https://thl.fi/en/web/thlfi-en/-/monitoring-wastewater-for-coronavirus-xbb-sublineage-of-omicron-variant-found-in-wastewater-follow-up-results-coming-in-january?redirect=%2Ffi%2Fajankohtaista%2Ftiedotteet-ja-uutiset%2Fkaikki-uutiset">Europe</a> and other places.</p>
<h2>How likely is XBB.1.5 to cause serious illness?</h2>
<figure class="align-center ">
<img alt="Illustration of five coronaviruses of different colours in a line" src="https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=217&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=217&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=217&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=272&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=272&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504766/original/file-20230116-12-o1ah4n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=272&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The XBB lineage emerged following natural co-infection of a human host with two Omicron subvariants, namely BA.2.10.1 and BA.2.75.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>There is limited data about the ability of XBB.1.5 to cause serious illness. According to the <a href="https://www.who.int/docs/default-source/coronaviruse/11jan2023_xbb15_rapid_risk_assessment.pdf">World Health Organization</a>, XBB.1.5 does not have any specific mutations that make it any more dangerous than its ancestral subvariants. </p>
<p>Nonetheless, XBB.1.5 is perceived as being equally capable of causing serious illness in elderly and immunocompromised persons compared to previous Omicron subvariants of concern.</p>
<h2>Are current mRNA vaccines effective against XBB.1.5?</h2>
<p>XBB.1.5 and XBB.1 are the Omicron subvariants with the <a href="https://www.who.int/docs/default-source/coronaviruse/11jan2023_xbb15_rapid_risk_assessment.pdf">greatest immune-evasive properties</a>. Therefore, one of the most contentious issues surrounding XBB.1.5 relates to the degree of protection afforded by currently available mRNA vaccines, including the latest bivalent booster formulations. </p>
<p><a href="https://doi.org/10.1038/s41591-022-02162-x">Researchers from the University of Texas</a> determined that first-generation and bivalent mRNA booster vaccines containing BA.5 result in lacklustre neutralizing antibody responses against XBB.1.5. A report (yet to be peer reviewed) from investigators at the <a href="https://doi.org/10.1101/2022.12.17.22283625">Cleveland Clinic</a> found that bivalent vaccines demonstrate only modest (30 per cent) effectiveness in otherwise healthy non-elderly people when the variants in the vaccine match those circulating in the community. </p>
<p>Furthermore, some experts believe the administration of bivalent boosters for the prevention of COVID-19 illness in otherwise healthy young individuals is <a href="http://doi.org/10.1056/NEJMp2215780">not medically justified</a> nor <a href="https://doi.org/10.1136/jme-2022-108449">cost-effective</a>. </p>
<p>In contrast, <a href="http://doi.org/10.1056/NEJMc2214293">public health experts from Atlanta, Ga. and Stanford, Calif.</a> reported that although the neutralizing antibody activity of bivalent booster vaccines against XBB.1.5 is 12 to 26 times less than antibody activity against the wild-type (original) SARS-CoV-2 virus, bivalent vaccines still perform better than monovalent vaccines against XBB.1.5. </p>
<p>However, <a href="https://doi.org/10.1016/j.cell.2022.12.018">investigators from Columbia University</a> in New York found that neutralizing antibody levels following bivalent boosting were up to 155–fold lower against XBB.1.5 compared to levels against the wild-type virus following monovalent boosting. </p>
<p>This suggests that neither monovalent nor bivalent booster vaccines can be relied upon to provide adequate protection against XBB.1.5.</p>
<h2>How can you protect yourself against XBB.1.5?</h2>
<figure class="align-center ">
<img alt="A blue sign reading 'wearing a mask is recommended,' in French and English" src="https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=536&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=536&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504744/original/file-20230116-18-xo2zgu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=536&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Standard infection control precautions including indoor masking, social distancing and frequent handwashing are effective measures against XBB.1.5 and other subvariants of concern.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Graham Hughes</span></span>
</figcaption>
</figure>
<p>The rapid evolution of SARS-CoV-2 continues to pose a challenge for the management of COVID-19 illness using available preventive and therapeutic agents. Of note, all currently available monoclonal antibodies targeting the spike protein of SARS-CoV-2 are <a href="https://doi.org/10.1016/j.cell.2022.12.018">deemed to be ineffective against XBB.1.5</a>. </p>
<p>Antiviral medicines such as remdesivir and Paxlovid may be considered for the treatment of eligible infected patients at high risk of progressing to severe disease.</p>
<p>Standard infection control precautions including indoor masking, social distancing and frequent handwashing are effective measures that can be employed for personal and population protection against XBB.1.5 and other subvariants of concern.</p>
<p>Although bivalent boosters may be considered for elderly, immunocompromised and other risk-averse individuals, their effectiveness in preventing COVID-19 illness due to XBB.1.5 remains uncertain. </p>
<h2>Why is XBB.1.5 nicknamed ‘Kraken’?</h2>
<p><a href="https://www.mountainviewtoday.ca/amp/lifestyle-news/kraken-subvariant-name-beats-alphabet-soup-moniker-for-xbb15-biologist-6351664">Some scientists have coined unofficially-recognized nicknames for XBB.1.5</a> and other SARS-CoV-2 subvariants of concern, arguing that they are easier to remember than generic alphanumeric designations. </p>
<p><a href="https://news.uoguelph.ca/2023/01/biologist-makes-headlines-on-new-covid-subvariant/">The ‘Kraken’ label for XBB.1.5 is currently in vogue</a> on social media sites and news outlets, and the nicknames ‘Gryphon’ and ‘Hippogryph’ have been used to denote the ancestral subvariants XBB and XBB.1, respectively. <a href="https://www.merriam-webster.com/dictionary/kraken">Kraken</a> refers to a mythological Scandinavian sea monster or giant squid, Gryphon (or <a href="https://www.merriam-webster.com/dictionary/griffin">Griffin</a>) refers to a legendary creature that is a hybrid of an eagle and a lion, while Hippogryph (or <a href="https://www.merriam-webster.com/dictionary/hippogriff">Hippogriff</a>) is a fictitious animal hybrid of a Gryphon and a horse. </p>
<p>Notwithstanding their potential utility as memory aids, the use of nicknames or acronyms in formal scientific discussions should be avoided.</p><img src="https://counter.theconversation.com/content/197602/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sameer Elsayed does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The XBB.1.5 subvariant — nicknamed ‘Kraken’ — is arguably the most genetically rich and most transmissible SARS-CoV-2 Omicron subvariant yet.Sameer Elsayed, Professor of Medicine, Pathology & Laboratory Medicine, and Epidemiology & Biostatistics, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1976002023-01-15T14:36:18Z2023-01-15T14:36:18ZCanada’s new COVID test rules: Targeting travellers from China will not stop globally circulating Omicron subvariant<figure><img src="https://images.theconversation.com/files/504511/original/file-20230113-22-8onu62.JPG?ixlib=rb-1.1.0&rect=330%2C0%2C6159%2C4369&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cathay Pacific crew members who worked on a flight from Hong Kong arrive at Vancouver International Airport. Canada now requires air travellers from China, Hong Kong and Macau to have a recent negative COVID-19 test result. </span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Darryl Dyck</span></span></figcaption></figure><p>In a throwback to January 2020, when the novel coronavirus SARS-CoV-2 began to be detected outside of China, many countries have again adopted measures targeted at travellers from China. These measures include <a href="https://www.cbc.ca/news/health/china-covid-global-concern-testing-requirements-1.6699690">flight restrictions, pre-departure testing</a> and <a href="https://www.africanews.com/2023/01/01/covid-19-morocco-bans-flights-from-china//">blanket entry bans</a>. </p>
<p>As of Jan. 5, 2023, air travellers from <a href="https://travel.gc.ca/travel-covid/travel-restrictions/covid-19-pre-boarding-test-requirements-china-hong-kong-macao">China, Hong Kong and Macau</a> over two years of age entering Canada must provide proof of a negative COVID test prior to departure. </p>
<p>This latest round of travel measures is in response to a dramatic surge in new coronavirus infections in China. </p>
<p>Following <a href="https://www.nytimes.com/2022/12/19/world/asia/china-zero-covid-xi-jinping.html">widespread protests</a> against the prolonged zero COVID policy in November 2022, the Chinese government <a href="https://www.reuters.com/world/china/chinas-rigid-zero-covid-19-policy-starts-thaw-2022-12-07/">dismantled its strictest COVID-19 rules</a> with remarkable speed. This included permission for Chinese nationals, who were largely banned from travelling abroad during the pandemic, to leave the country as of Jan. 8. </p>
<p>The abrupt change in direction, combined with low population immunity, led to a <a href="https://www.bbc.com/news/world-asia-china-64208127">spike in infections and deaths</a>. This unfolding tragedy, amid limited transparency and data sharing by the Chinese government, is stoking fears worldwide of a potential <a href="https://www.theguardian.com/commentisfree/2022/dec/21/china-covid-surge-vaccination-data-infected">new variant of concern</a>. </p>
<p>Although governments have justified the measures as science-based, consensus on effective border management during this pandemic remains elusive. Chinese officials were swift to dismiss the new measures as <a href="https://www.theguardian.com/world/2023/jan/03/china-criticises-other-countries-for-excessive-covid-travel-rules">politically motivated</a>. This is difficult to dispute given that previous measures targeting select countries were <a href="https://www.npr.org/sections/coronavirus-live-updates/2021/11/28/1059619823/omicron-travel-bans-covid">ineffective in preventing introduction of globally circulating new variants such as Omicron</a>.</p>
<h2>Effective use of testing as a travel measure</h2>
<p><a href="https://doi.org/10.1186/s12916-021-01975-w">Available evidence</a> shows that testing combined with other measures can reduce SARS-CoV-2 introduction from a high- to a low-incidence setting, if applied early, universally and stringently. </p>
<p>Testing must be aligned with the evolving science about the accuracy of different tests and the incubation periods of different variants. Testing must also be appropriately combined with other proven measures, notably quarantine and contact tracing, to prevent onward transmission. </p>
<figure class="align-center ">
<img alt="A plane silhouetted against a gray sky" src="https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=362&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=362&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=362&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=454&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=454&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504513/original/file-20230113-13-kez3o2.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=454&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The introduction of pre-departure testing alone, for selected travellers arriving from targeted countries, is unlikely to reduce the spread of new variants.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Jonathan Hayward</span></span>
</figcaption>
</figure>
<p>The introduction of pre-departure testing alone, for selected travellers arriving from targeted countries, will not advance these goals for several reasons. By the time a variant or subvariant is identified as concerning, the volume of human mobility worldwide means <a href="https://www.cbc.ca/news/health/covid-china-travel-canada-testing-1.6701771">it will have already spread</a> to other countries not targeted. </p>
<p>The two known Omicron lineages driving the surge in infections among a low-immunity Chinese population — subvariants BA.5.2 and BF.7 — are described as “<a href="https://www.who.int/news/item/04-01-2023-tag-ve-statement-on-the-3rd-january-meeting-on-the-covid-19-situation-in-china">known and… already circulating in other countries</a>” during much of 2022. </p>
<p>Should a new variant emerge, targeted measures like those now being applied would still have limited preventive effect. This is because global patterns of travel mean passengers mix with large numbers of other people along their journeys, often transiting through several countries. </p>
<p>Moreover, reliance on a single 48-hour pre-departure testing window overlooks variable incubation periods, false negatives, or new exposures during the time window prior to departure. </p>
<p>Finally, it makes little sense to test selected incoming travellers to slow introductions while lifting public health measures and allowing uncontrolled domestic transmission.</p>
<h2>How should travel measures be used now?</h2>
<p>Following the uncoordinated and often chaotic use of travel measures worldwide, our research at the <a href="https://www.pandemics-borders.org/">Pandemics and Borders Project</a> identifies <a href="https://www.pandemics-borders.org/resources/publications">lessons for their use</a> three years into the COVID-19 pandemic. </p>
<p>First, there is unlikely to be capacity or political will to test travellers universally and repeatedly to prevent the introduction of any new variant of concern. Instead, randomized testing of all travellers, with <a href="https://uploads-ssl.webflow.com/5f331097bc003b401120fa8f/60e9368c02e522753398ca7c_advisorypanel-report-comments.pdf">genomic sequencing of positive test results</a>, would provide critical surveillance data points at a time when the virus is rapidly evolving and moving about through travel. </p>
<p>This should be supplemented with <a href="https://theconversation.com/sewage-surveillance-how-scientists-track-and-identify-diseases-like-covid-19-before-they-spread-148307">testing of wastewater</a> from, for example, airplanes and cruise ships. Testing of travellers for population and sentinel surveillance would support early warning of new variants of concern. </p>
<figure class="align-center ">
<img alt="A child wearing a face mask and riding on a scooter passes by a worker in protective suit" src="https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504512/original/file-20230113-12-3hbyqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A worker in protective suit on his way to collect COVID samples from the lockdown residents in Beijing, on Dec. 1, 2022.</span>
<span class="attribution"><span class="source">(AP Photo/Andy Wong)</span></span>
</figcaption>
</figure>
<p>Second, proven travel measures should be reframed as practices to enhance <a href="https://doi.org/10.1016/j.lanwpc.2021.100209">risk mitigation</a>, enabling rather than restricting travel. Public health messaging should challenge populist-stoked narratives that, for example, wearing masks during a flight is a <a href="https://www.theguardian.com/commentisfree/2023/jan/05/covid-cases-nhs-culture-war-face-masks?CMP=Share_iOSApp_Other">violation of individual liberty</a>. Instead, appropriate use of testing, masking and vaccination enhances personal freedoms by creating a safer environment for all travellers. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-was-ensnared-in-canadas-harsh-and-unscientific-african-travel-ban-174272">I was ensnared in Canada's harsh and unscientific African travel ban</a>
</strong>
</em>
</p>
<hr>
<p>Finally, travel measures should be applied in ways that enhance — rather than deter — data sharing. <a href="https://www.washingtonpost.com/outlook/2021/11/29/omicron-travel-ban-covid/">The use of targeted travel restrictions against southern African countries in 2021 did little to slow the Omicron variant</a>. The restrictions may have allowed politicians to reassure their constituents at home that something was being done but, in practice, reporting countries were simply <a href="https://www.foreignaffairs.com/articles/world/2021-12-09/world-needs-better-strategy-covid-travel-restrictions?check_logged_in=1">punished</a> for alerting the world to an already globally circulating variant. </p>
<p>Similarly, insufficient data sharing is currently cited as a key reason for travel measures targeting Chinese travellers. Rather than complying, however, the Chinese government has begun to retaliate by <a href="https://www.bbc.com/news/world-asia-64220149">restricting short term visas</a> for travellers from South Korea and Japan. </p>
<p>With the virus continuing to change and circulate globally in the foreseeable future, governments would do well not to repeat past mistakes. Instead they should seek ways to improve how decisions are made on the use of travel measures during the current and future public health emergencies.</p><img src="https://counter.theconversation.com/content/197600/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer Fang is funded by the New Frontiers in Research Fund and the Canadian Institutes of Health Research. The Pacific Institute on Pathogens, Pandemics and Society receives funding from the BC Ministry of Health.</span></em></p><p class="fine-print"><em><span>Julianne Piper is funded by the New Frontiers in Research Fund, the Canadian Institutes of Health Research for her work on the Pandemics and Borders project. The Pacific Institute on Pathogens, Pandemics and Society receives funding from the BC Ministry of Health.</span></em></p><p class="fine-print"><em><span>Kelley Lee receives funding from the Canadian Institutes of Health Research, New Frontiers in Research Fund, and Social Sciences and Humanities Research Council of Canada for work related to global health governance. The Pacific Institute on Pathogens, Pandemics and Society receives funding from the BC Ministry of Health.</span></em></p>Canada’s new COVID-19 testing requirement for travellers arriving from China is unlikely to prevent the spread of new subvariants.Jennifer Fang, Research fellow, Pacific Institute on Pathogens, Pandemics and Society, Simon Fraser UniversityJulianne Piper, Research Fellow, Health Sciences, Simon Fraser UniversityKelley Lee, Professor and Canada Research Chair in Global Health Governance; Scientific Co-Director, Pacific Institute on Pathogens, Pandemics and Society, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1972652023-01-12T05:54:10Z2023-01-12T05:54:10ZThe ‘kraken’ COVID variant XBB.1.5 is rising quickly in the US – here’s what it could mean for the UK<figure><img src="https://images.theconversation.com/files/503993/original/file-20230111-18-xrpegb.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4278%2C2048&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/kraken-covid-variant-xbb15-recombinant-covid19-2246507257">CI Photos/Shutterstock</a></span></figcaption></figure><p>The heavily mutated omicron variant of SARS-CoV-2, the virus that causes COVID-19, was <a href="https://www.nature.com/articles/s41586-022-04411-y">first detected in late 2021</a>. </p>
<p>Due to the many mutations in the spike protein (a protein on the surface of SARS-CoV-2 that allows the virus to attach to our cells) omicron was able to quickly become the dominant SARS-CoV-2 variant. These mutations allowed it <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1010733">to bind to respiratory cells</a> more tightly than previous variants, rendering it more infectious. </p>
<p>Owing to the dominance of omicron, thanks to these mutations, the past several months have seen the emergence of <a href="https://pubmed.ncbi.nlm.nih.gov/36619228/">many subvariants</a> of omicron (scientists have identified <a href="https://twitter.com/TRyanGregory/status/1611778593478017024?s=20&t=DDvAOWddbPb-WG7A5mjD8w">more than 650</a> to date).</p>
<p>The latest variant to worry health professionals and virologists alike is XBB.1.5, nicknamed “<a href="https://twitter.com/TRyanGregory/status/1611778593478017024?s=20&t=DDvAOWddbPb-WG7A5mjD8w">kraken</a>” by a group of scientists that has been naming new variants after mythological creatures to make the virus’ evolution more accessible to the public. Here’s what we know about it.</p>
<p>XBB.1.5 is a derivative of the <a href="https://theconversation.com/xbb-and-bq-1-what-we-know-about-these-two-omicron-cousins-193591">XBB variant of omicron</a>. XBB was never designated as <a href="https://www.who.int/news/item/27-10-2022-tag-ve-statement-on-omicron-sublineages-bq.1-and-xbb">a variant of concern</a> by the World Health Organization because data shows that, while XBB’s mutations enable it to evade our immune systems better than previous omicron subvariants, it doesn’t appear to be causing <a href="https://covid19.who.int/#:%7E:text=Globally%2C%20as%20of%205%3A09pm,vaccine%20doses%20have%20been%20administered.">an increase in infection rates</a>.</p>
<p>In addition to the mutations that XBB.1 has, XBB.1.5 also carries <a href="https://www.ecdc.europa.eu/en/news-events/update-sars-cov-2-variants-ecdc-assessment-xbb15-sub-lineage">a mutation called S486P</a> in the spike protein region. Preliminary <a href="https://www.biorxiv.org/content/10.1101/2023.01.03.522427v2">laboratory studies</a>, yet to be peer-reviewed, have shown that, similar to XBB.1, XBB.1.5 is less sensitive to antibodies acquired from vaccination than previous variants XBB and BQ1.1. So it’s very good at evading our immune response.</p>
<p>The same <a href="https://www.biorxiv.org/content/10.1101/2023.01.03.522427v2">preprint</a> showed that XBB.1.5 was able to bind to ACE2 (the receptor the virus uses to infect our cells) more strongly than these earlier variants. This is the characteristic that made <a href="https://pubmed.ncbi.nlm.nih.gov/36030585/">the original omicron variant</a> so infectious and so dominant. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/where-is-the-next-covid-variant-pi-a-virologist-explains-why-omicron-is-continuing-to-dominate-195857">Where is the next COVID variant, pi? A virologist explains why omicron is continuing to dominate</a>
</strong>
</em>
</p>
<hr>
<p>Having first been detected in <a href="https://www.ecdc.europa.eu/en/news-events/update-sars-cov-2-variants-ecdc-assessment-xbb15-sub-lineage">October 2022</a> in the US, XBB.1.5 has spread rapidly in the country and is now responsible for <a href="https://covid.cdc.gov/covid-data-tracker/#variant-summary">around 28%</a> of all new infections. Elsewhere, XBB.1.5 has been detected in at least <a href="https://outbreak.info/situation-reports/xbb.1.5*%20%5Bomicron%20(xbb.1.5.x)%5D?loc=USA&loc=USA_US-CA&selected=Worldwide&overlay=false">23 countries</a>, including the UK. But according to the most recent data, it accounts for <a href="https://covid19.sanger.ac.uk/lineages/raw?lineageView=1&lineageSearch=xbb&lineages=A%2CB%2CB.1.1.7%2CB.1.617.2%2CB.1.1.529%2CBA.1.1%2CBA.2%2CBA.4%2CBA.5%2CXBB%2CXBB.1.5&colours=7%2C3%2C1%2C6%2C2%2C8%2C4%2C0%2C5%2C0%2C&xMin=2022-05-14&show=A%2CB%2CB.1.1.7%2CB.1.617.2%2CB.1.1.529%2CBA.1.1%2CBA.2%2CBA.4%2CBA.5%2CXBB%2CXBB.1.5">only 4%</a> of COVID infections in England. </p>
<p>Given what we’re seeing in the US, it’s likely that XBB.1.5 will become the dominant strain in the UK and Europe in time. But as there are always differences in populations (for example, vaccination rates and social behaviour) it’s hard to predict exactly how things will play out.</p>
<figure class="align-center ">
<img alt="A woman at a bus station wearing a mask." src="https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504012/original/file-20230111-5012-nk0pgp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">XBB.1.5 is rife in the US, but not in the UK and Europe at this stage.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cheerful-woman-wearing-sterile-protective-medical-1670515414">HBRH/Shutterstock</a></span>
</figcaption>
</figure>
<h2>So should we be worried?</h2>
<p>Though some of XBB.1.5’s characteristics are concerning, the <a href="https://covid19.who.int/#:%7E:text=Globally%2C%20as%20of%205%3A09pm,vaccine%20doses%20have%20been%20administered.">real-world infection data</a> is not showing an overall increase in infections or deaths globally or in the US (where XBB.1.5. is rife) at present. </p>
<p>It’s <a href="https://www.ecdc.europa.eu/en/news-events/update-sars-cov-2-variants-ecdc-assessment-xbb15-sub-lineage">too early to tell</a> whether infections from XBB.1.5 are more severe than previous variants, however <a href="https://www.sciencemediacentre.org/expert-reaction-to-the-omicron-xbb-1-5-covid-variant/">experts agree</a> that there is no evidence at this stage that it poses any higher risk than variants that have come before it.</p>
<p>Experts also agree that <a href="https://www.sciencemediacentre.org/expert-reaction-to-the-omicron-xbb-1-5-covid-variant/">vaccination</a> will continue to protect against serious disease and death from XBB.1.5. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hybrid-immunity-a-combination-of-vaccination-and-prior-infection-probably-offers-the-best-protection-against-covid-183943">Hybrid immunity: a combination of vaccination and prior infection probably offers the best protection against COVID</a>
</strong>
</em>
</p>
<hr>
<p>With a new variant, there’s always the risk it will affect clinically vulnerable people <a href="https://www.nhs.uk/conditions/coronavirus-covid-19/people-at-higher-risk/">more severely</a>. Older people and those with conditions that affect their immune systems mount weaker responses to COVID vaccines, so are less protected than the “healthy” population. This means variants that spread more easily or can better evade our immune system may be more likely to infect these people if they’re exposed. </p>
<p>So, while COVID continues to circulate, it’s best to take extra precautions when meeting vulnerable people such as wearing a mask, washing your hands thoroughly, ventilating the space that you are in (or even meeting outdoors), and not meeting them at all if you are ill.</p><img src="https://counter.theconversation.com/content/197265/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Grace C Roberts works at the University of Leeds and receives funding from the MRC.</span></em></p>XBB.1.5, or ‘kraken’, can evade our immune systems better than earlier variants, and appears to be more infectious. But it’s not cause for alarm.Grace C Roberts, Research Fellow in Virology, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1962102022-12-11T19:07:11Z2022-12-11T19:07:11ZIs my RAT actually working? How to tell if your COVID test can detect Omicron<figure><img src="https://images.theconversation.com/files/499734/original/file-20221208-12-65pkn0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1000%2C666&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/asian-woman-using-rapid-antigen-test-2056195568">Shutterstock</a></span></figcaption></figure><p>You’ve tested negative for COVID using a rapid antigen test (RAT), but are a close contact of a positive family member and have symptoms. So you might be wondering if you’re really COVID-negative or if the test is working as well as it should.</p>
<p>There are many reasons why your RAT may not give you <a href="https://theconversation.com/15-things-not-to-do-when-using-a-rapid-antigen-test-from-storing-in-the-freezer-to-sampling-snot-176364">the results</a> <a href="https://theconversation.com/my-rats-are-negative-but-i-still-think-i-might-have-covid-should-i-get-a-pcr-test-194527">you expect</a>. But one factor is whether RATs can detect the Omicron variant of SARS-CoV-2 (the virus that causes COVID).</p>
<p>We know the virus has mutated during the pandemic. So health authorities and researchers are investigating whether RATs can still detect the <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants">more recent versions</a> of the virus.</p>
<p>The good news is, based on the <a href="https://www.tga.gov.au/sites/default/files/2022-10/post-market-review-of-antigen-and-rapid-antigen-tests-table.pdf">limited data released</a>, all RATs meant for use at home in Australia that have been independently tested so far seem to be able to detect Omicron. The bad news is that not all RATs have been independently tested yet. Yours might be one of those.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/15-things-not-to-do-when-using-a-rapid-antigen-test-from-storing-in-the-freezer-to-sampling-snot-176364">15 things not to do when using a rapid antigen test, from storing in the freezer to sampling snot</a>
</strong>
</em>
</p>
<hr>
<h2>What do mutations have to do with RATs?</h2>
<p>RATs diagnose COVID infection by detecting specific viral proteins. So there are concerns that as the virus evolves and produces altered viral proteins, this may affect the tests’ ability to diagnose COVID as well as they detected previous variants.</p>
<p>Whether RATs can adequately detect Omicron has been raised by authorities and researchers in various countries including <a href="https://www.bmj.com/content/378/bmj-2022-071215">The Netherlands</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/35458384/">Belgium</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/36339133/">Chile</a>, as well as Australia.</p>
<p>One <a href="https://journals.asm.org/doi/10.1128/jcm.01097-22">Australian study</a>
tested six RATs on Delta, and Omicron lineages BA.4, BA.5 and BA.2.75. The researchers found the kits performed equally well across the different samples at higher viral loads (higher concentrations of the virus), although one kit’s overall sensitivity fell below minimum sensitivity requirements. </p>
<p>However, <a href="https://pubmed.ncbi.nlm.nih.gov/36339133/">some international studies</a> have found RATs are less able to detect Omicron, particularly when <a href="https://pubmed.ncbi.nlm.nih.gov/36339133/">viral loads are lower</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/my-rats-are-negative-but-i-still-think-i-might-have-covid-should-i-get-a-pcr-test-194527">My RATs are negative but I still think I might have COVID. Should I get a PCR test?</a>
</strong>
</em>
</p>
<hr>
<h2>So what’s the case in Australia?</h2>
<p>Australia’s regulator, the Therapeutic Goods Administration (TGA), initially relied on <a href="https://www.tga.gov.au/products/covid-19/covid-19-tests/post-market-review-antigen-and-rapid-antigen-tests">test data</a> provided by RAT manufacturers to determine the test kit met World Health Organization <a href="https://www.who.int/publications/m/item/technical-specifications-for-selection-of-essential-in-vitro-diagnostics-for-sars-cov-2">standards</a> for acceptable sensitivity (ability to detect a positive case).</p>
<p>The TGA also requires manufacturers to send updated test data as new variants arise to demonstrate their test still meets those WHO standards.</p>
<p>But the TGA has also commissioned <a href="https://www.tga.gov.au/products/covid-19/covid-19-tests/post-market-review-antigen-and-rapid-antigen-tests">independent testing of RATs</a> to verify how well they detect the more recent COVID variants.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1590104415033335808"}"></div></p>
<p>They are tested for their ability to detect the wild-type virus (the original strain), the Delta variant, and the Omicron variant. The TGA does not state which specific lineages (descendents) of Omicron are included in the testing. </p>
<p>As it completes its analysis on individual tests (or groups of tests), the TGA reports them in a <a href="https://www.tga.gov.au/sites/default/files/2022-10/post-market-review-of-antigen-and-rapid-antigen-tests-table.pdf">table that’s publicly available</a>, which will be updated as more data come in.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-centaurus-to-xbb-your-handy-guide-to-the-latest-covid-subvariants-and-why-some-are-more-worrying-than-others-192945">From Centaurus to XBB: your handy guide to the latest COVID subvariants (and why some are more worrying than others)</a>
</strong>
</em>
</p>
<hr>
<h2>What does the table tell us?</h2>
<p>You can look up the brand name, manufacturer and batch number of the RAT you have at home. Look for those labelled “self-tests” (more on the different types of tests and their results later).</p>
<p>The most important columns in the table are those that indicate whether the kit passed its independent validation. Look for four ticks to indicate the kit meets minimum standards for detecting the original virus, Delta and Omicron variants, and has passed the quality test. A cross indicates is has not passed that component of the validation.</p>
<p>Haven’t found a result for your RAT? </p>
<p>If a product comes in two versions – a self-test and a type of test used in health-care facilities known as a point-of-care test (POCT in the table) – only one may be tested.</p>
<p>If that’s the case, the symbol † means testing was only done on one version and you can use those results for your test. Look for a matching registration number to make sure you’re comparing like with like.</p>
<p>The final column indicates what type of data the manufacturer has provided. Some manufacturers have tested the sensitivity of their kits for Omicron lineages BA.4 and BA.5.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-there-so-many-new-omicron-sub-variants-like-ba-4-and-ba-5-will-i-be-reinfected-is-the-virus-mutating-faster-182274">Why are there so many new Omicron sub-variants, like BA.4 and BA.5? Will I be reinfected? Is the virus mutating faster?</a>
</strong>
</em>
</p>
<hr>
<h2>What does the table not tell us?</h2>
<p>Just because your test has no ticks or crosses against it, this doesn’t mean it can’t detect Omicron. It could be that the independent validation has yet to be completed or uploaded to the table. So the jury is out.</p>
<p>The table also does not tell us what lineages of Omicron were tested for, although in some cases the manufacturer has supplied clinical test data. </p>
<p>The table data were only current as of October. Seeing as the number of cases of sub-variant infections <a href="https://theconversation.com/what-can-we-expect-from-this-latest-covid-wave-and-how-long-is-it-likely-to-last-194444">has risen since then</a>, so we don’t really know if that is impacting on the sensitivity of even those tests that have recently been validated.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-can-we-expect-from-this-latest-covid-wave-and-how-long-is-it-likely-to-last-194444">What can we expect from this latest COVID wave? And how long is it likely to last?</a>
</strong>
</em>
</p>
<hr>
<h2>I’ve grappled with the table, now what?</h2>
<p>If your brand of RAT has the ticks, particularly for Omicron, it has been assessed has having an acceptable sensitivity. If you are buying a RAT, check the table to see if that brand has been tested for sensitivity to the Omicron variant. </p>
<p>If your test has been sitting in a cupboard for months, check the expiry date before you use it. Also consider whether it has been stored at the correct temperature during that time (the instruction leaflet will tell you what that is).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-accurate-is-your-rat-3-scenarios-show-its-about-more-than-looking-for-lines-175515">How accurate is your RAT? 3 scenarios show it's about more than looking for lines</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/196210/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thea van de Mortel teaches into the Griffith University Master of Infection Prevention and Control program. </span></em></p>Some results of independent testing of rapid antigen tests available in Australia have been made public. Here’s what the data tell us.Thea van de Mortel, Professor, Nursing, School of Nursing and Midwifery, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1929452022-11-02T19:01:55Z2022-11-02T19:01:55ZFrom Centaurus to XBB: your handy guide to the latest COVID subvariants (and why some are more worrying than others)<figure><img src="https://images.theconversation.com/files/492011/original/file-20221027-20344-89v7f2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3500%2C1797&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/vector-coronavirus-2019ncov-virus-background-disease-1660037152">Shutterstock</a></span></figcaption></figure><p>The Omicron variant of concern has splintered into multiple subvariants. So we’ve had to get our heads around these mutated forms of SARS-CoV-2, the virus that causes COVID-19, <a href="https://theconversation.com/why-are-there-so-many-new-omicron-sub-variants-like-ba-4-and-ba-5-will-i-be-reinfected-is-the-virus-mutating-faster-182274">including</a> BA.1 and the more recent BA.5. </p>
<p>We’ve also seen recombinant forms of the virus, <a href="https://theconversation.com/whats-the-new-omicron-xe-variant-and-should-i-be-worried-180584">such as XE</a>, arising by genetic material swapping between subvariants. </p>
<p>More recently, <a href="https://www.who.int/news/item/27-10-2022-tag-ve-statement-on-omicron-sublineages-bq.1-and-xbb">XBB</a> and <a href="https://theconversation.com/omicron-bq-1-and-bq-1-1-an-expert-answers-three-key-questions-about-these-new-covid-variants-192873">BQ.1</a> have been in the news.</p>
<p>No wonder it’s hard to keep up.</p>
<p>The World Health Organization (WHO) has had to rethink how it describes all these subvariants, <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants">now labelling ones</a> we need to be monitoring more closely.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-there-so-many-new-omicron-sub-variants-like-ba-4-and-ba-5-will-i-be-reinfected-is-the-virus-mutating-faster-182274">Why are there so many new Omicron sub-variants, like BA.4 and BA.5? Will I be reinfected? Is the virus mutating faster?</a>
</strong>
</em>
</p>
<hr>
<h2>What’s the big deal with all these subvariants?</h2>
<p>Omicron and its subvariants are still causing the <a href="https://www.who.int/publications/m/item/weekly-epidemiological-update-on-covid-19---19-october-2022">vast majority</a> of COVID cases globally, including in <a href="https://doi.org/10.33321/cdi.2022.46.73">Australia</a>.</p>
<p>Omicron subvariants have their own specific mutations that <a href="https://www.sciencedirect.com/science/article/pii/S2666634022001386">might make them</a> more transmissible, cause more severe disease, or evade our immune response.</p>
<p>Omicron and its subvariants have pushed aside previous variants of concern, the ones that led to waves of Alpha and Delta earlier in the pandemic. </p>
<p>Now, in Australia, the main Omicron subvariants circulating are BA.2.75, and certain versions of BA.5. More on these later.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Waves of virus" src="https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=248&fit=crop&dpr=1 600w, https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=248&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=248&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=312&fit=crop&dpr=1 754w, https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=312&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/491844/original/file-20221026-15-jsbvpb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=312&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Viral genomes from Australia: once we had Alpha and Delta waves. Now we have waves of Omicron subvariants.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We still don’t fully understand the driving forces behind <a href="https://academic.oup.com/mbe/article/39/2/msac013/6509545">the emergence</a> and spread of certain SARS-CoV-2 subvariants.</p>
<p>We can, however, assume the virus will keep evolving, and new variants (and subvariants) will continue to emerge and spread in this wave-like pattern.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-is-a-smart-virus-that-can-affect-dna-but-that-doesnt-mean-you-can-pass-it-on-to-your-kids-192185">COVID is a 'smart virus' that can affect DNA – but that doesn't mean you can pass it on to your kids</a>
</strong>
</em>
</p>
<hr>
<h2>How do we keep track of this all?</h2>
<p>To monitor these subvariants, the WHO has defined a <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants">new category</a>, known as “Omicron subvariants under monitoring”.</p>
<p>These are ones that have specific combinations of mutations known to confer some type of advantage, such as being more transmissible than others currently circulating.</p>
<p>Researchers and health authorities keep track of circulating subvariants by sequencing the genetic material from viral samples (for instance, from PCR testing or from <a href="https://www.coronavirus.vic.gov.au/wastewater-testing">wastewater sampling</a>). They then upload the results to global databases (such as <a href="https://gisaid.org">GISAID</a>) or national ones (such as <a href="https://www.cdgn.org.au/austrakka">AusTrakka</a>). </p>
<p>These are the Omicron subvariants authorities are keeping a closer eye on for any increased risk to public health. </p>
<h2>Newer versions of BA.5</h2>
<p>The BA.5 subvariant that arose in early February 2022 is still accumulating more mutations.</p>
<p>The WHO is monitoring BA.5 versions that carry at least one of <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants">five additional mutations</a> (known as S:R346X, S:K444X, S:V445X, S:N450D and S:N460X) in the spike gene.</p>
<p>The spike gene codes for the part of the virus that <a href="https://www.nature.com/articles/s41401-020-0485-4">recognises and fuses with human cells</a>. We are particularly concerned about mutations in this gene as they might increase the virus’ ability to bind with human cells. </p>
<p>Throughout recent months, BA.5 has been the dominant subvariant in Australia. However, BA.2.75 has now established a foothold.</p>
<h2>BA.2.75 or Centaurus</h2>
<p>The BA.2.75 subvariant, sometimes called Centaurus, was first documented in December 2021. It possibly emerged in India, but has been detected around the globe. </p>
<p>This includes in Australia, where more than 400 sequences have been uploaded to the GISAID database since June 2022.</p>
<p>This subvariant has <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants">up to 12 mutations</a> in its spike gene. It seems to <a href="https://www.health.govt.nz/system/files/documents/pages/sars-cov-2-variant-of-concern-update-27sep22.pdf">spread more effectively</a> than BA.5. This is probably due to being better able to infect our cells, and avoiding the immune response driven by previous infection with other variants.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1547072800992940032"}"></div></p>
<h2>BJ.1</h2>
<p>This was first detected in early September 2022 and has a set of 14 spike gene mutations. </p>
<p>It has mostly been detected <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1109820/Technical-Briefing-46.pdf">in India</a> or in infections coming from this area.</p>
<p>We know very little about the impact of its mutations and at the time of writing, there was only one Australian sequence reported.</p>
<h2>BA.4.6 or Aeterna</h2>
<p>BA.4.6, sometimes called Aeterna, was detected in January 2022 and has been spreading rapidly in the United States and the United Kingdom. </p>
<p>There have been more than 800 sequences uploaded to the GISAID database in Australia since May 2022.</p>
<p>It may be more <a href="https://theconversation.com/another-new-covid-variant-is-spreading-heres-what-we-know-about-omicron-ba-4-6-189939">easily transmitted</a> from one person to the next due to its spike gene mutations.</p>
<p>Early data suggests it is better able to resist <a href="https://www.biorxiv.org/content/10.1101/2022.09.05.506628v1">cocktails of therapeutic antibodies</a> compared with BA.5. This makes <a href="https://www.biorxiv.org/content/biorxiv/early/2022/08/10/2022.08.09.503384.full.pdf">antibody therapies</a>, such as Evusheld, less effective against it.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/another-new-covid-variant-is-spreading-heres-what-we-know-about-omicron-ba-4-6-189939">Another new COVID variant is spreading – here's what we know about omicron BA.4.6</a>
</strong>
</em>
</p>
<hr>
<h2>BA.2.3.20</h2>
<p>This was first detected in the US in August 2022. It has a set of nine mutations in the spike gene, including a rare double mutation (A484R). </p>
<p>Like BA.2.75, this subvariant is <a href="https://www.health.govt.nz/system/files/documents/pages/sars-cov-2-variant-of-concern-update-27sep22.pdf">probably better able to</a> infect our cells and avoid the immune response driven by previous infection.</p>
<p>There are more than 100 Australian genomic sequences reported in the GISAID database, all from August 2022.</p>
<h2>XBB</h2>
<p>This recombinant version of the virus was detected in August 2022. It is a result of the swapping of genetic material between BA.2.10.1 and BA.2.75. It has 14 extra mutations in its spike gene compared with BA.2. </p>
<p>Although there have only been 50 Australian genomic sequences reported in GISAID since September, we anticipate cases will rise. Lab studies <a href="https://www.biorxiv.org/content/10.1101/2022.09.15.507787v3.full.pdf">indicate</a> therapeutic antibodies <a href="https://aci.health.nsw.gov.au/covid-19/critical-intelligence-unit/sars-cov-2-variants">don’t work so well</a> against it, with XBB showing strong resistance.</p>
<p>Although XBB appears to be able to spread faster than BA.5, there’s <a href="https://www.health.govt.nz/system/files/documents/pages/sars-cov-2-variant-of-concern-update-27sep22.pdf">no evidence</a> so far it causes more severe disease.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1582465413257916416"}"></div></p>
<h2>How about BQ.1?</h2>
<p>Although it is not on the WHO list of subvariants under monitoring, cases of the <a href="https://theconversation.com/omicron-bq-1-and-bq-1-1-an-expert-answers-three-key-questions-about-these-new-covid-variants-192873">BQ.1 subvariant</a> are rising in Australia. BQ.1 contains mutations that help the virus <a href="https://www.biorxiv.org/content/10.1101/2022.09.15.507787v3">evade existing immunity</a>. This means infection with other subvariants, including BA.5, may not protect you against BQ.1.</p>
<p>In the meantime, your best <a href="https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2022-09-01/04-COVID-Link-Gelles-508.pdf">protection against severe COVID</a>, whichever subvariant is circulating, is to make sure your booster shots are up-to-date. Other ways to prevent SARS-CoV-2 infection include wearing a fitted mask, avoiding crowded spaces with poor ventilation, and washing your hands regularly. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/omicron-bq-1-and-bq-1-1-an-expert-answers-three-key-questions-about-these-new-covid-variants-192873">Omicron BQ.1 and BQ.1.1 – an expert answers three key questions about these new COVID variants</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/192945/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sebastian Duchene receives funding from the Australian Research Council and the National Health and Medical Research Council. </span></em></p><p class="fine-print"><em><span>Ash Porter does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are so many forms of the virus, it’s hard to keep up. Here’s what to expect next as the virus mutates and recombines.Ash Porter, Research officer, The Peter Doherty Institute for Infection and ImmunitySebastian Duchene, Australian Research Council Future Fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1928732022-10-31T09:55:49Z2022-10-31T09:55:49ZOmicron BQ.1 and BQ.1.1 – an expert answers three key questions about these new COVID variants<figure><img src="https://images.theconversation.com/files/491316/original/file-20221024-1583-txsqwo.jpg?ixlib=rb-1.1.0&rect=10%2C0%2C7178%2C4041&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/sarscov2-viruses-binding-ace2-receptors-on-1687909009">Kateryna Kon/Shutterstock</a></span></figcaption></figure><p>Two new omicron subvariants, BQ.1 and BQ.1.1, are quickly gaining traction in the US, collectively accounting for <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">27% of infections</a> as of October 29. Both are descendants of BA.5, the omicron variant that has dominated around the world for some months.</p>
<p>Although they appear to be most common in the US at this stage, BQ.1 and BQ.1.1 have also been identified in <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1109820/Technical-Briefing-46.pdf">the UK</a> and several <a href="https://twitter.com/MoritzGerstung/status/1577667129100337152">countries in Europe</a>, with the European Centre for Disease Prevention and Control (ECDC) having classified BQ.1 as a <a href="https://www.ecdc.europa.eu/en/covid-19/variants-concern">variant of interest</a>. </p>
<p>Based on modelling estimates, <a href="https://www.ecdc.europa.eu/en/publications-data/spread-sars-cov-2-omicron-variant-sub-lineage-bq1-eueea">the ECDC expects</a> that by mid-November to the beginning of December 2022, more than 50% of COVID infections will be due to BQ.1 and BQ.1.1. By the beginning of 2023, they could account for more than 80% of cases.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1584281761772511232"}"></div></p>
<p>When we hear about new COVID variants, three key questions spring to mind: is it more transmissible compared with previous variants? Can it cause more severe illness? And can it escape our immune response? Let’s take a look at what we know so far.</p>
<h2>1. Are these variants more transmissible?</h2>
<p>Transmissibility refers to the capacity of a pathogen to be able to be passed from one person to another. This characteristic is determined <a href="https://www.nature.com/articles/s41579-021-00535-6#:%7E:text=Transmissibility%20is%20determined%20by%20the%20infectivity%20of%20the,environmental%20stress%20exerted%20on%20the%20pathogen%20during%20transmission.">by many factors</a> relating to the pathogen, its host and the environment.</p>
<p>At this stage, we have limited data on how transmissible these two new variants are. But BQ.1.1 appears to be highly transmissible, with <a href="https://twitter.com/CorneliusRoemer/status/1576716682512388096">social media reports</a> calculating it took only 19 days to grow eight-fold from five sequences to 200 sequences. </p>
<p>Although BQ.1 and BQ.1.1 currently comprise a small proportion of all COVID cases globally, in some countries the proportion of cases is increasing at a rate which suggests it’s more transmissible than other circulating variants.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-vaccines-an-annual-booster-like-the-flu-shot-could-be-the-way-forward-191301">COVID vaccines: an annual booster like the flu shot could be the way forward</a>
</strong>
</em>
</p>
<hr>
<h2>2. Can they escape our immune system?</h2>
<p>The ECDC suggests the observed increase in the growth rate of BQ.1 is probably driven mainly by <a href="https://www.ecdc.europa.eu/en/publications-data/spread-sars-cov-2-omicron-variant-sub-lineage-bq1-eueea">immune escape</a>. This refers to the virus’ capacity to evade our immune response from prior infection or vaccination. </p>
<p>BQ.1 and BQ.1.1 contain mutations to the spike protein, a protein on the surface of SARS-CoV-2 (the virus that causes COVID-19) which allows it to attach to and infect our cells. These <a href="https://arstechnica.com/science/2022/10/ba-5-is-finally-fading-sublineages-bq-1-and-bq-1-1-rise-from-variant-stew/">mutations include</a> K444T, N460K, L452R and F486V. BQ.1.1 contains an additional mutation, R346T, also found in <a href="https://www.nature.com/articles/s41586-022-04980-y">the BA.5 variant</a>.</p>
<p>These mutations have been associated with significant <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00642-9/fulltext">immune escape</a> and <a href="https://www.cell.com/action/showPdf?pii=S1931-3128%2821%2900082-2">antibody evasion</a>. </p>
<figure class="align-center ">
<img alt="A young woman wearing a mask." src="https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/491350/original/file-20221024-21-g1xh5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">These new variants could threaten the dominance of BA.5.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-wearing-medical-protective-mask-outdoors-1666586704">goffkein.pro/Shutterstock</a></span>
</figcaption>
</figure>
<p>One <a href="https://www.biorxiv.org/content/10.1101/2022.09.15.507787v3">study</a> indicated that it’s likely that immunity induced by infection from previous omicron sublineages and vaccination will not provide broad protection against BQ.1.1 infection. However this study is a preprint, meaning it’s yet to be peer-reviewed. </p>
<p>Although the current <a href="https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/vaccine-induced-immunity.html">COVID vaccines</a> and previous infections provide good protection against severe disease, they do not provide full protection from infection or reinfection. Likewise, while they reduce COVID transmission, they do not prevent it entirely. And these new variants appear to have the highest capacity for immune evasion yet. That said, COVID vaccines will continue to offer strong protection against severe disease and death.</p>
<h2>3. Can they cause more severe illness?</h2>
<p>We still don’t know much about the severity of illness associated with BQ.1 or BQ.1.1. But based on the limited data available, the news is good on this front. There’s <a href="https://www.ecdc.europa.eu/en/publications-data/spread-sars-cov-2-omicron-variant-sub-lineage-bq1-eueea">no evidence</a> that BQ.1 is associated with more severe illness than BA.4 and BA.5. </p>
<p>Worryingly though, <a href="https://www.biorxiv.org/content/10.1101/2022.09.15.507787v3">a recent preprint study</a> suggests that BQ.1.1 could be resistant to Evusheld, an antibody therapy designed to protect people who are immunocompromised and don’t respond as well to COVID vaccines.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/another-new-covid-variant-is-spreading-heres-what-we-know-about-omicron-ba-4-6-189939">Another new COVID variant is spreading – here's what we know about omicron BA.4.6</a>
</strong>
</em>
</p>
<hr>
<h2>The pandemic is not over yet</h2>
<p>Beyond the US and Europe, BQ.1 and BQ.1.1 have also been identified in other countries around in the world including <a href="https://www.health.govt.nz/news-media/news-items/omicron-subvariant-bq11-detected-new-zealand">New Zealand</a>, <a href="https://www.thaipbsworld.com/first-case-of-drug-resistant-omicron-bq-1-sub-variant-found-in-thailand/">Thailand</a>, <a href="https://www.channelnewsasia.com/singapore/singapore-bq1-bq11-omicron-covid-19-subvariants-detected-imported-moh-3025856">Singapore</a> and <a href="https://toronto.citynews.ca/2022/10/04/omicron-subvariant-covid-fall/">Canada</a>, where they’ve been detected <a href="https://regina.ctvnews.ca/new-omicron-variants-detected-in-regina-wastewater-u-of-r-1.6093817">in wastewater</a>. Sewage samples often give us <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8421077/">a good indication</a> of possible COVID spikes. </p>
<p>The continued emergence of new COVID variants indicates that the virus is very much still with us, and rapidly evolving. As we face resurgences heading into winter in the northern hemisphere, we need to keep our eyes on these and any other new variants, and carefully observe how they behave.</p>
<p>We also need studies which test how well the new <a href="https://theconversation.com/covid-vaccine-how-the-new-bivalent-booster-will-target-omicron-188840">bivalent vaccines</a> – those which target omicron alongside the original strain of SARS-CoV-2 – work against BQ.1 and BQ.1.1.</p><img src="https://counter.theconversation.com/content/192873/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Manal Mohammed does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Two new omicron subvariants, BQ.1 and BQ.1.1 could lead to another COVID surge. Here’s what we know so far.Manal Mohammed, Senior Lecturer, Medical Microbiology, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1908752022-10-13T12:18:13Z2022-10-13T12:18:13ZCOVID-19 rapid tests can breed confusion – here’s how to make sense of the results and what to do, according to 3 testing experts<figure><img src="https://images.theconversation.com/files/489443/original/file-20221012-5658-i7ulul.jpg?ixlib=rb-1.1.0&rect=725%2C0%2C7921%2C5743&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Technique matters when it comes to getting a sufficient amount of virus for a rapid test.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/young-asian-mom-carrying-out-a-covid-19-self-test-royalty-free-image/1361590313?phrase=negative%20covid%20test&adppopup=true">Images By Tang Ming Tung/Digital Vision via Getty Images</a></span></figcaption></figure><p>As fall temperatures set in, <a href="https://theconversation.com/when-should-you-get-the-new-covid-19-booster-and-the-flu-shot-now-is-the-right-time-for-both-190826">cold and flu season</a> gets into full swing and holiday travel picks up, people will undoubtedly have questions about COVID-19 testing. Is this the year people can finally return to large gatherings for traditional celebrations? What role does testing play when deciding whether to go out or stay home?</p>
<p>Adding to the confusion are personal accounts of people who are experiencing confusing or seemingly contradictory test results.</p>
<p><a href="https://profiles.umassmed.edu/display/14945561">We are</a> <a href="https://profiles.umassmed.edu/display/26835692">part of a team</a> that has <a href="https://www.nih.gov/research-training/medical-research-initiatives/radx/radx-programs">developed and tested SARS-CoV-2 tests</a> <a href="https://scholar.google.com/citations?user=OJ3tLoQAAAAJ&hl=en">since the early days</a> of the pandemic. Additionally, some of us are <a href="https://publichealth.jhu.edu/faculty/965/yukari-carol-manabe">infectious disease specialists</a> with <a href="https://scholar.google.com/citations?user=0qpdrlIAAAAJ&hl=en">decades of experience</a>. </p>
<p>Our insights from both the cutting edge of rapid testing research as well as our clinical perspectives from working directly with patients can help people figure out how to make the best use of rapid tests.</p>
<h2>Multiple negative tests, then a positive - why?</h2>
<p>SARS-CoV-2, the virus that causes COVID-19, <a href="https://theconversation.com/whats-the-difference-between-a-pcr-and-antigen-covid-19-test-a-molecular-biologist-explains-170917">takes time to build up</a> in the body, like many other viruses and bacteria that cause respiratory illness. Typically it takes two to three days to test positive after exposure. Our research group <a href="https://doi.org/10.1093/infdis/jiab337">has demonstrated this</a>, <a href="https://doi.org/10.1371/journal.pbio.3001216">as have others</a>. </p>
<p>Rapid tests detect parts of the virus that are present in the sample collected from your nose or mouth. If the virus has not replicated to a high enough level in that part of your body, a test will be negative. Only when the amount of virus is high enough will a person’s test become positive. For most omicron variants in circulation today, this is one to three days, depending on the initial amount of virus you get exposed to.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/_NMO3d8jq20?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A newscaster rapid tests for COVID-19 on live TV.</span></figcaption>
</figure>
<h2>Why do some people test positive for extended periods of time?</h2>
<p>It’s important to clarify which type of test we’re talking about in this situation. Studies <a href="https://doi.org/10.1111/trf.16015">have shown that</a> some people can <a href="https://doi.org/10.1002/ams2.525">test positive for a month or more</a> with a PCR test. The reason for this is twofold: PCR tests are capable of detecting extremely small amounts of genetic material, and fragments of the virus can remain in the respiratory system for a long time before being cleared.</p>
<p>When it comes to rapid tests, there are reports that some people test positive for an <a href="https://doi.org/10.1093/infdis/jiac391">extended period of time</a> with the current strains of the omicron variant compared with earlier variants. Several <a href="https://doi.org/10.1093/cid/ciac693">studies show that</a> most people <a href="https://doi.org/10.1093/cid/ciac510">no longer test positive after five to seven days</a> from their first positive test, but between 10% to 20% of people continue to test positive for 10 to 14 days. </p>
<p>But why it takes longer for some people to clear the virus than others is still unknown. Possible explanations include <a href="https://www.today.com/health/health/still-testing-positive-covid-19-rcna12099">a person’s vaccination status</a> or the ability of one’s immune system to clear the virus. </p>
<p>In addition, a small number of people who have been treated with <a href="https://aspr.hhs.gov/COVID-19/Therapeutics/Products/Paxlovid/Pages/default.aspx">the oral antiviral drug Paxlovid</a> have tested negative on rapid antigen tests, with no symptoms, only to <a href="https://emergency.cdc.gov/han/2022/pdf/CDC_HAN_467.pdf">“rebound” seven to 14 days after</a> their initial positive test. In these cases, people sometimes experience recurring or even occasionally worse symptoms than they had before, along with positive rapid test results. People who experience this should isolate again, as it has been shown that people with rebound cases <a href="https://doi.org/10.1056%2FNEJMc2206449">can transmit the virus to others</a>.</p>
<h2>Why do I have COVID-19 symptoms but still test negative?</h2>
<p>There are several possible explanations for why you might get negative rapid tests even when you have COVID-like symptoms. The most likely is that you have an infection of something other than SARS-CoV-2. </p>
<p>Many different viruses and bacteria can make us sick. Since mask mandates have been lifted in most settings, many viruses that didn’t circulate widely during the pandemic, <a href="https://theconversation.com/when-should-you-get-the-new-covid-19-booster-and-the-flu-shot-now-is-the-right-time-for-both-190826">like influenza</a> and <a href="https://www.cdc.gov/rsv/index.html">Respiratory Syncytial Virus, or RSV</a>, are becoming common once again and making people sick. </p>
<p>Second, <a href="https://www.nytimes.com/2022/06/02/well/live/covid-testing-household-transmission.html">a mild COVID-19 infection</a> in a person that’s been vaccinated and boosted may result in a viral level that’s high enough to cause symptoms but too low to result in a positive rapid test. </p>
<p>Finally, the use of poor technique when sampling your nose or mouth may result in too little virus to yield a positive test. Many tests with nasal swabbing require you to swab for at least 15 seconds in each nostril. A failure to swab according to package instructions could result in a negative test. </p>
<p><a href="https://doi.org/10.1093/infdis/jiab337">Our previous studies</a> show that if you are symptomatic and do two rapid antigen tests 48 hours apart rather than just one, you are <a href="https://theconversation.com/just-how-accurate-are-rapid-antigen-tests-two-testing-experts-explain-the-latest-data-180405">more highly likely to test positive</a> if you are infected with SARS-CoV-2.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/DItTMLVrr38?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Self-swabbing: It sounds kind of cringy, but it’s really not so bad.</span></figcaption>
</figure>
<h2>Do rapid tests work against the current strains of SARS-CoV-2?</h2>
<p><a href="https://doi.org/10.7326/M22-0760">Multiple studies</a> have examined the <a href="https://doi.org/10.1001/jamanetworkopen.2022.28143">performance of rapid tests</a> against the omicron variant. </p>
<p>Fortunately, these studies show that all the rapid tests that have been authorized for emergency use by the U.S. Food and Drug Administration <a href="https://doi.org/10.1101/2022.02.27.22271090">detect the current omicron variants</a> just as well as previous variants such as alpha and delta. If a symptomatic person tests positive on a rapid test, they likely have COVID-19. If you are exposed to someone who has COVID-19, or have symptoms but receive a negative test, you should take another test in 48 hours. If you then test positive or if your symptoms get worse, contact your health care provider. </p>
<h2>What’s the best way to use and interpret rapid tests before gatherings?</h2>
<p>Testing remains an important tool to identify infected people and limit the spread of the virus. It’s still a good idea to take a rapid test before visiting people, especially older people and those with weakened immune systems. </p>
<p>If you believe you may be infected, the FDA <a href="https://www.fda.gov/medical-devices/safety-communications/home-covid-19-antigen-tests-take-steps-reduce-your-risk-false-negative-fda-safety-communication">recently updated their testing guidance</a> largely based on <a href="https://doi.org/10.1101/2022.08.05.22278466">data our lab collected</a>. The testing regimen most likely to identify if you’re infected is to take two tests 48 hours apart if you have symptoms. If you don’t have symptoms, take three tests, one every 48 hours.</p>
<h2>Does a positive test mean you can spread COVID to others?</h2>
<p>The Centers for Disease Control and Prevention recommends that if you test positive for COVID-19, you should stay home for at least <a href="https://www.cdc.gov/coronavirus/2019-ncov/your-health/isolation.html">five days from the date of your positive test and isolate from others</a>. People are likely to be most infectious during these first five days. After you end isolation and feel better, consider taking a rapid test again. </p>
<p>If you have two negative tests 48 hours apart, you are most likely no longer infectious. If your rapid tests are positive, you may still be infectious, even if you are past day 10 after your positive test. If possible, you should wear a mask. <a href="https://doi.org/10.1101/2022.09.26.22280387">Multiple studies have shown</a> a correlation between <a href="https://doi.org/10.1126/science.abi5273">the time an individual tests positive</a> on a rapid test and when live virus can be collected from a person, which is a common way to determine if someone is infectious. </p>
<p>Testing is still an important tool to keep people safe from COVID-19 and to avoid spreading it to others. Knowing your status and deciding to test is a decision that individuals make based on their own tolerance for risk around contracting COVID-19. </p>
<p>People who are older or at higher risk of severe disease may want to test frequently after an exposure or if they have symptoms. Some people may also be worried about having COVID-19 and transmitting it to others who may be at higher risk for hospitalization. When combined with other measures such as vaccination and staying home when you’re sick, testing can reduce the impact of COVID-19 on all of our lives in the coming months.</p><img src="https://counter.theconversation.com/content/190875/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathaniel Hafer receives funding from NIH grants UL1TR001453 and U54HL143541.</span></em></p><p class="fine-print"><em><span>Apurv Soni receives funding from NIH grants UL1TR001453 and U54HL143541.</span></em></p><p class="fine-print"><em><span>Yukari Manabe receives funding from the NIH. She has received research grant support to Johns Hopkins University from Hologic, Cepheid, Roche, ChemBio, Becton Dickinson, miDiagnostics, and has provided consultative support to Abbott.</span></em></p>Rapid tests can be an incredibly useful tool for early detection of COVID-19. Unfortunately, they sometimes leave people with more questions than answers.Nathaniel Hafer, Assistant Professor of Molecular Medicine, UMass Chan Medical SchoolApurv Soni, Assistant Professor of Medicine, UMass Chan Medical SchoolYukari Manabe, Associate Director of Global Health Research and Innovation Professor of Medicine, Johns Hopkins UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1912352022-10-02T11:38:22Z2022-10-02T11:38:22ZAdding COVID-19 to ‘designated diseases’ could boost vaccine uptake among children<figure><img src="https://images.theconversation.com/files/486925/original/file-20220927-12-6l3yjo.JPG?ixlib=rb-1.1.0&rect=0%2C0%2C3600%2C2398&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A 10-year-old Toronto boy receives his COVID-19 vaccine shot from a Toronto Public Health nurse at a children's vaccine clinic at Scotiabank Arena in December 2021. </span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Chris Young</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/adding-covid-19-to--designated-diseases--could-boost-vaccine-uptake-among-children" width="100%" height="400"></iframe>
<p>My research includes <a href="https://www.canlii.org/en/commentary/doc/2021CanLIIDocs13616?zoupio-debug#!fragment/">the moral and legal aspects</a> and <a href="https://theconversation.com/most-of-us-support-mandatory-vaccines-for-schoolkids-but-is-it-good-policy-114580">policy implications</a> of childhood vaccination. COVID-19’s effects on children has an impact on that research. And these effects appear to be changing, making the need for widespread COVID-19 vaccine uptake among children more urgent.</p>
<p>Early in the pandemic, evidence suggested children <a href="https://www.cfp.ca/content/66/5/332?ijkey=8d86709c3b675e02c97b406521c7c50c4e2f86f3&keytype2=tf_ipsecsha">generally avoided severe COVID-19 infections</a>. That rosier picture is now fading. Emerging research signals that children’s susceptibility to SARS-CoV-2, the virus that causes COVID-19, has increased in <a href="https://www.news-medical.net/news/20220912/Review-of-COVID-19-in-children-before-and-after-SARS-CoV-2-Delta-and-Omicron-variant-emergence.aspx">“frequency and severity”</a> over the course of the pandemic.</p>
<p>One newly released study of British Columbia’s Lower Mainland chronicles the <a href="https://www.straight.com/ovid-19-pandemic/living/study-coauthored-by-dr-bonnie-henry-documents-colossal-increase-in-covid-19-in-metro">dramatic rise in infections among those under 19</a>. This surge in childhood infection with the Omicron variant is consistent with <a href="https://globalnews.ca/news/9133714/alberta-kids-covid-hospitalization-increase/">estimates in other parts of Canada</a> <a href="https://www.who.int/news/item/11-08-2022-interim-statement-on-covid-19-vaccination-for-children">and beyond</a>.</p>
<p>Increased frequency of infections among children will necessarily yield a <a href="https://www.burnabynow.com/coronavirus-covid-19-local-news/1000-bc-kids-hospitalized-thousands-left-with-long-covid-5832177">greater number of cases with severe outcomes</a>, including <a href="https://health-infobase.canada.ca/covid-19/#a7">hospitalizations and deaths</a>. Children with co-morbidities are <a href="https://doi.org/10.1016/j.lana.2022.100337">especially vulnerable</a> to severe COVID-19 outcomes. </p>
<p>Like adults, children can also suffer from long COVID that can <a href="https://www.itnonline.com/content/lasting-lung-damage-seen-children-and-teens-after-covid">damage their lungs</a>, <a href="https://www.parents.com/kids/health/how-covid-19-can-affect-your-childs-brain/">their brains</a> and create a host of other <a href="http://dx.doi.org/10.15585/mmwr.mm7102e2">health problems</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/do-kids-get-long-covid-and-how-often-a-paediatrician-looks-at-the-data-166277">Do kids get long COVID? And how often? A paediatrician looks at the data</a>
</strong>
</em>
</p>
<hr>
<h2>Low vaccination uptake among minors</h2>
<p>A <a href="https://www.publichealthontario.ca/-/media/documents/ncov/factsheet/2021/06/lp/fact-sheet-covid-19-preventive-layers.pdf?sc_lang=en">multi-pronged approach</a> to restrict transmission, <a href="https://www.publichealthontario.ca/-/media/documents/ncov/covid-wwksf/2021/08/wwksf-wearing-masks-children.pdf?sc_lang=en">including masking</a>, is advised over any one single preventive measure. This is likely even more important with <a href="https://www.cbsnews.com/news/bf-7-ba-2-75-covid-variants-rise-cdc-tracking/">new variants</a> on the horizon.</p>
<p>Yet vaccination remains one of the <a href="https://www.canada.ca/en/public-health/services/diseases/coronavirus-disease-covid-19/vaccines/effectiveness-benefits-vaccination.html">best means to protect against severe outcomes</a> when <a href="https://www.ama-assn.org/delivering-care/public-health/what-doctors-wish-patients-knew-about-breakthrough-covid-infections">breakthrough infection</a> occurs. Additionally, vaccination <a href="https://www.mcgill.ca/oss/article/covid-19-medical/how-reduce-risk-getting-long-covid#:%7E:text=What%20did%20make%20the%20largest,a%20single%20dose%20did%20not.">may decrease the likelihood</a> of long COVID. The <a href="https://www.ontario.ca/page/covid-19-vaccines#section-5">Ontario government recommends vaccination</a> for those under 18.</p>
<p>That’s why it’s alarming that vaccine uptake among minors of the primary series of two doses, particularly for those under 12, <a href="https://www.cbc.ca/news/canada/toronto/covid-vaccine-children-ontario-uptake-1.6591216">remains low</a>.</p>
<p>Compared to the <a href="https://health-infobase.canada.ca/covid-19/vaccination-coverage/">provincial average of 90 per cent for those 12 and above</a>, only 41 per cent of Ontario children aged five to 11 have completed their primary series. Uptake among those under five is almost non-existent, with just six per cent receiving their first doses in the two months since Health Canada approved a COVID-19 vaccine for this cohort. Numbers across the country are roughly similar. </p>
<p>Notably, Ontario <a href="https://www.cp24.com/news/ontario-won-t-add-covid-19-to-list-of-nine-diseases-that-elementary-and-secondary-students-must-be-immunized-against-official-1.5642776">declined to add COVID-19</a> to the list of “designated diseases” in its <a href="https://www.ontario.ca/laws/regulation/130261">Immunization of School Pupils Act</a> last fall, despite <a href="https://www.cbc.ca/news/canada/windsor/student-vaccinations-windsor-1.6294437">support for this move by some school boards</a> and both <a href="https://ontarioliberal.ca/ontario-liberals-will-add-covid-19-vaccines-to-list-of-universal-school-shots/">the opposition Liberals</a> <a href="https://www.ontariondp.ca/news/ndp-calls-urgent-push-get-kids-vaccinated">and NDP</a>.</p>
<p>It’s time to revisit that decision.</p>
<p>Adding COVID-19 to the act will not make COVID-19 vaccination mandatory for school entry. Whether childhood vaccines should be mandatory <a href="https://albertaviews.ca/vaccinations-mandatory/">is a separate debate</a>. But it may, nonetheless, help address the COVID-19 vaccine uptake among the province’s school-aged children.</p>
<figure class="align-center ">
<img alt="Children stand in a line in a schoolyard." src="https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=414&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=414&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=414&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486926/original/file-20220927-12-hghib3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Children wait in a physical distancing circle at a Toronto elementary school in September 2020.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Nathan Denette</span></span>
</figcaption>
</figure>
<h2>Vaccine requirements for school entry</h2>
<p>Ontario, <a href="https://www.canlii.org/en/nb/laws/stat/snb-1998-c-p-22.4/latest/snb-1998-c-p-22.4.html">New Brunswick</a> and <a href="https://www.canlii.org/en/bc/laws/regu/bc-reg-146-2019/latest/bc-reg-146-2019.html">British Columbia</a> are the only Canadian jurisdictions that have vaccination requirements for school entry. But minors aren’t required in any of those provinces to be vaccinated to attend day care, elementary or high school. </p>
<p>British Columbia’s regulation explicitly makes the duty a <em>reporting</em> one only. Ontario requirements are somewhat different, as the parental duty is to <a href="https://www.ontario.ca/laws/statute/90i01">“cause the pupil to complete the prescribed program of immunization.”</a> Yet the duty does not apply where the parent “has filed a statement of conscience or religious belief.”</p>
<p>This means a parent can refuse to have their child vaccinated against any or all of the designated diseases by signing and having notarized a government-issued form affirming a <a href="https://hpepublichealth.ca/wp-content/uploads/2019/08/ispa-exemption-september-2017.pdf">“sincere belief.”</a> </p>
<p>In practical terms, this makes the duty a reporting one in Ontario as well. The situation in New Brunswick is <a href="https://www2.gnb.ca/content/dam/gnb/Departments/h-s/pdf/en/CDC/HealthProfessionals/412-SchoolExceptionForm.pdf">virtually the same</a>.</p>
<p>Where Ontario and New Brunswick differ, however, is that Ontario requires that parents seeking a sincere-belief exemption also attend an “education session.” <a href="https://www.hdsb.ca/our-board/Documents/Correspondence-from-Chair-of-Board/Sept-8-2021-Correspondence-from-the-Chair-of-the-Board.pdf">For some, access to this education session is the real benefit of listing COVID-19 among the designated diseases</a>. </p>
<figure class="align-center ">
<img alt="A nurse wearing a mask vaccinates a boy in a white T-shirt also wearing a mask." src="https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486924/original/file-20220927-2496-ikht7k.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A young boy is vaccinated during the first day of vaccination for children aged five to 11 in Montréal in November 2021.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Paul Chiasson</span></span>
</figcaption>
</figure>
<h2>Vaccine hesitancy and COVID-19</h2>
<p>Vaccine hesitancy is attributed as the cause for low vaccine uptake when it comes to COVID-19. But it’s complicated.</p>
<p>While a small percentage of parents reject all vaccines, many more are <a href="https://immunize.ca/sites/default/files/resources/1792e.pdf">selective about vaccines</a> and are generally more cautious about newer ones than older ones. In fact, generally positive parental attitudes about routine childhood vaccines are a poor indicator of their attitudes toward COVID-19 vaccines, both <a href="https://doi.org/10.1016/j.vaccine.2021.10.002">in Canada</a> <a href="https://doi.org/10.3389/fpubh.2021.752323">and elsewhere</a>. </p>
<p>When it came into effect in Ontario in 2017, the requirement to undergo an education session for those seeking a sincere-belief exemption made little difference in attitude because vaccine uptake against the designated diseases, <a href="https://www.unicef-irc.org/publications/pdf/rc11_eng.pdf">while less than optimal</a>, was still generally high. </p>
<p>And education sessions can be like sermons to that dogged minority whose minds are made up on the topic. Mandatory education <a href="https://doi.org/10.1016/j.socscimed.2022.115120">can also be counterproductive</a> and cause people to become more entrenched in their opinions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/five-reasons-why-young-people-should-get-a-covid-booster-vaccine-189411">Five reasons why young people should get a COVID booster vaccine</a>
</strong>
</em>
</p>
<hr>
<p>However, there is a very large gap between low childhood vaccination rates for COVID-19 and the high rates for routine childhood vaccines. </p>
<h2>Not anti-vaxxers</h2>
<p>This suggests that most parents who have so far refused COVID-19 shots are not hard-core anti-vaxxers. This may provide an opening to sway more parents to have their children vaccinated.</p>
<p>Research about parental attitudes toward COVID-19 vaccination is fast-moving, and understandably there are large gaps. But the general conclusion is that vaccination campaigns targeted to specific demographics can increase uptake. </p>
<p>It’s unclear whether adding COVID-19 to the list of “designated diseases” in Ontario or elsewhere in Canada would have the desired effect. And certainly the design and content of education sessions matter. </p>
<p>But it defies logic to have a regulatory scheme already in place committed to increasing “the protection of the health of children” and decide that a pandemic is not a good time to use it.</p><img src="https://counter.theconversation.com/content/191235/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alison Braley-Rattai does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Adding COVID-19 to a list of ‘designated diseases’ will not make vaccination mandatory for school entry. But it may help increase COVID-19 vaccine uptake among children.Alison Braley-Rattai, Associate Professor, Labour studies, Brock UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1907362022-09-25T20:03:31Z2022-09-25T20:03:31ZOmicron-specific vaccines may give slightly better COVID protection – but getting boosted promptly is the best bet<p>Vaccines (predominantly mRNA vaccines) have been our front-line defence against COVID and have <a href="https://www.medicalnewstoday.com/articles/covid-19-vaccines-saved-20-million-lives-in-1-year#Quantifying-the-lives-sa">saved millions of lives</a>.</p>
<p>Despite the emergence of genetically distinct COVID <a href="https://www.who.int/activities/tracking-SARS-CoV-2-variants/">variants</a> throughout the pandemic, we’ve relied on vaccines that target the spike protein from the virus originally detected in Wuhan, China. While still providing excellent protection, mRNA vaccines are less effective against newer variants with immunity waning <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2115481">within months of immunisation</a>.</p>
<p>Australia’s Omicron bivalent (two-strain) COVID vaccine has been <a href="https://www.health.gov.au/ministers/the-hon-mark-butler-mp/media/australias-first-bivalent-covid-19-vaccine-to-join-rollout">approved for use</a> and will be rolled out as stocks of the original vaccines need replacing. </p>
<p>While we hope they will provide better protection than existing vaccines, the little data we have so far suggests they only provide slightly better protection.</p>
<p>So, if you’re <a href="https://www.health.gov.au/initiatives-and-programs/covid-19-vaccines/getting-your-vaccination/booster-doses">eligible for your fourth dose</a>, it makes sense to get boosted with whichever COVID vaccine you’re offered now – rather than waiting until the Omicron-specific boosters enter circulation. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/better-covid-vaccines-are-on-the-way-what-do-they-do-and-what-technology-might-we-see-in-future-189531">Better COVID vaccines are on the way. What do they do? And what technology might we see in future?</a>
</strong>
</em>
</p>
<hr>
<h2>Playing catch up with new variants</h2>
<p>One key technological advance with mRNA vaccines is the ability to modify the mRNA sequence that encodes the spike protein in SARS-CoV-2 (the virus that causes COVID). This means scientists can target the viral spike protein and respond to the viral variants currently circulating. </p>
<p>But it still takes time to manufacture a recalibrated mRNA vaccine, then test it, distribute it and get it into people’s arms. </p>
<p>Earlier in the pandemic, Moderna produced a bivalent vaccine that also targeted the Beta variant. Initial lab tests <a href="https://www.nature.com/articles/s41591-021-01527-y">showed</a> boosting with this variant-specific vaccine increased antibodies against Beta approximately two times better than the boost provided by the original vaccine.</p>
<p>However development was discontinued because Beta was replaced by other COVID variants. </p>
<p>As long as SARS-CoV-2 evolves, keeping up with it is going to remain a challenge for variant-specific vaccines. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-were-on-a-global-panel-looking-at-the-staggering-costs-of-covid-17-7m-deaths-and-counting-here-are-11-ways-to-stop-history-repeating-itself-190658">We were on a global panel looking at the staggering costs of COVID – 17.7m deaths and counting. Here are 11 ways to stop history repeating itself</a>
</strong>
</em>
</p>
<hr>
<h2>Testing new vaccines now</h2>
<p>So how do scientists determine if bivalent vaccines work better than existing vaccines? </p>
<p>The gold standard is a clinical trial that assesses protection from disease. Early in the pandemic when few people had immunity to SARS-CoV-2, this was relatively straight forward. Starting with a baseline of no immunity makes it easier to design a trial to assess the protection provided by vaccines. </p>
<p>The situation is a lot more complicated now, with much of the world’s population vaccinated, previously infected or both – often multiple times. </p>
<p>Measuring relative effectiveness in a clinical trial comparing two vaccines in such a diverse population exposed to unpredictable waves of infection requires large numbers of study participants – and lots of time and money. </p>
<p>As an alternative, we can examine indicators of protection. Antibodies are generated by the immune system when we’re exposed to the SARS-CoV-2 spike protein, either via vaccination or infection. The aim is to generate lots of antibodies that bind to the surface of the spike protein and stop the virus infecting cells. </p>
<p>Scientists can recruit study participants who know their vaccination and infection history and take their baseline antibody levels. Then they can be boosted with either the standard mRNA vaccine or the variant-modified bivalent vaccine. The level of virus-neutralising antibodies in the blood can then be assessed in the lab after boosting. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1571659947246751744"}"></div></p>
<h2>How effective is the Omicron booster?</h2>
<p>The Moderna COVID bivalent booster targets the ancestral virus and Omicron BA.1 subvariant. It has been <a href="https://www.health.gov.au/news/atagi-statement-on-use-of-the-moderna-bivalent-originalomicron-vaccine">approved for use</a> in Australia and will be rolled out when our stocks of existing Moderna boosters have been exhausted. </p>
<p>The bivalent vaccine will then be offered to adults who are due to have their third or fourth doses. </p>
<p><a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2208343">Lab-based studies</a> assessing antibody responses suggest the bivalent vaccine offers 1.5 to 2 times improved immunity over the boost provided by the original vaccine.</p>
<p>However, it’s unclear how much better they will be than existing boosters at protecting people from disease, particularly given BA.1 has been replaced by Omicron sub-variants. These have <a href="https://www.nature.com/articles/s41586-022-04980-y">several mutations</a> that distinguish them from BA.1 and so the bivalent Omicron vaccine is no longer a perfect match. </p>
<p>To try and understand vaccine effectiveness in the absence of a dedicated clinical trial, researchers can model the relationship between lab-based antibody studies and previous clinical trials to predict how well new vaccines will protect from disease. </p>
<p>This <a href="https://www.medrxiv.org/content/10.1101/2022.08.25.22279237v1">type of analysis</a> shows the original vaccine is quite good at restoring protection against disease caused by different variants when given as a booster. </p>
<p>Variant-modified vaccines such as the newly approved Omicron booster are predicted to improve that by 5–10%, depending on the variant and level of existing immunity. This might seem like a small improvement but it could mean additional lives saved. </p>
<p>That said, you are at much greater risk of disease if it has been several months since your last booster. That’s why it’s best to get boosted as soon as you’re eligible, rather than waiting for an Omicron-specific booster.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1549830290687885312"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/even-mild-covid-raises-the-chance-of-heart-attack-and-stroke-what-to-know-about-the-risks-ahead-190552">Even mild COVID raises the chance of heart attack and stroke. What to know about the risks ahead</a>
</strong>
</em>
</p>
<hr>
<h2>What might come next for the vaccine rollout?</h2>
<p>The government has accepted the Australian Technical Advisory Group on Immunisation (ATAGI) advice to wait until current Moderna booster stocks run out before putting the bivalent Omicron boosters into circulation. </p>
<p>This seems like the right call, given the Omicron boosters probably offer only a modest improvement in protection against the Omcicron sub-variants currently circulating. </p>
<p>In the future we might see annual COVID boosters adapted to the currently circulating strains or predicted strains, like season flu shots. There appears to be a desire to do this in the United States with the Federal Drug Administration fast-tracking authorisation of booster mRNA vaccines that target the Omicron BA.4/BA.5 subvariants, before data is available on <a href="https://www.nbcnews.com/health/health-news/fda-authorizes-pfizers-modernas-updated-covid-booster-shots-rcna44825">how well they work</a>.</p>
<p>Rather than constantly updating COVID vaccines, an alternative approach is to develop a “variant-proof” vaccine that targets multiple SARS-CoV-2 variants. We could combine this with treatments like <a href="https://theconversation.com/nasal-covid-19-vaccines-help-the-body-prepare-for-infection-right-where-it-starts-in-your-nose-and-throat-183790">nose sprays</a> that stimulate immunity against a range of viruses. </p>
<p>For now, bivalent vaccines work as well, if not a little better, than the original vaccines so transitioning to them makes sense.</p><img src="https://counter.theconversation.com/content/190736/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathan Bartlett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As the virus that causes COVID evolves, keeping up with it remains a challenge for variant-specific vaccines. The booster you can get now is the best one to get.Nathan Bartlett, Associate Professor, School of Biomedical Sciences and Pharmacy, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1907872022-09-16T14:57:46Z2022-09-16T14:57:46ZThe WHO has advised against the use of two antibody therapies against COVID – here’s what that means<figure><img src="https://images.theconversation.com/files/485089/original/file-20220916-25-zzufuq.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4019%2C3024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sotrovimab and casirivimab-imdevimab are no longer recommended for patients with COVID.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/melbourne-australia-1st-november-2021-person-2078827789">ice_blue/Shutterstock</a></span></figcaption></figure><p>New guidance from the <a href="https://www.bmj.com/content/370/bmj.m3379">World Health Organization</a> (WHO) strongly advises against using the antibody therapies sotrovimab and casirivimab-imdevimab to treat patients with COVID-19.</p>
<p>This guidance, published in the British Medical Journal, replaces previous conditional recommendations for the use of these drugs. It’s based on emerging evidence that they’re not likely to work against current COVID variants such as omicron.</p>
<p>This means that, at least for the time being, there are no recommended antibody therapies to treat COVID. There are, however, still other treatment options. Let’s take a look.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1570665071138799617"}"></div></p>
<p>We know that severe COVID is driven by collateral damage from our own immune system. Some of the most effective COVID treatments are anti-inflammatory medicines, which reduce exaggerated immune responses against the virus. Strong evidence continues to support the use of drugs such as <a href="https://www.covid19treatmentguidelines.nih.gov/therapies/immunomodulators/corticosteroids/#:%7E:text=Multiple%20randomized%20trials%20indicate%20that,to%20lung%20injury%20and%20multisystem">corticosteroids</a>, <a href="https://jamanetwork.com/journals/jama/fullarticle/2781881">anti-IL-6</a> and <a href="https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(22)00219-X/fulltext">baricitinib</a>.</p>
<p>Separate to anti-inflammatory drugs, we have two types of therapies that directly target SARS-CoV-2, the virus that causes COVID-19. These are antiviral drugs and antibody treatments. </p>
<p>Antiviral drugs allow the virus to enter our cells but prevent it from replicating, thereby reducing the impact of an infection. </p>
<p>Remdesivir, which was originally developed for hepatitis C, <a href="https://www.nejm.org/doi/full/10.1056/NEJMc2207519">retains efficacy</a> against omicron sub-variants BA.2.12.1, BA.4 and BA.5 in the lab. In the new guidance the WHO has conditionally recommended remdesivir to treat patients with severe COVID, but has advised against its use for patients who are critically unwell, based on results from a series of recent randomised trials.</p>
<p>Other antivirals include molnupiravir, which the WHO continues to conditionally recommend, and nirmatrelvir and ritonavir (a combination known as Paxlovid), which is recommended strongly. These drugs are taken orally, while remdesivir is administered intravenously.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-antiviral-drugs-are-a-vital-weapon-but-misusing-them-could-backfire-186959">COVID: antiviral drugs are a vital weapon – but misusing them could backfire</a>
</strong>
</em>
</p>
<hr>
<p>Meanwhile, antibody therapies work by coating a protein on the surface of SARS-CoV-2, called the spike protein, thereby blocking the virus from entering human cells. They can also help eliminate infected cells which have been hijacked by the virus.</p>
<p>Sotrovimab is one such antibody therapy. It’s a monoclonal antibody, which means it only targets a specific region of the virus’s spike protein. In <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2107934">clinical trials</a> conducted before the omicron variant emerged, sotrovimab reduced the risk of disease progression.</p>
<p>This led to its emergency authorisation by the <a href="https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-additional-monoclonal-antibody-treatment-covid-19">US Food and Drug Administration</a> and the UK’s <a href="https://www.gov.uk/government/news/mhra-approves-xevudy-sotrovimab-a-covid-19-treatment-found-to-cut-hospitalisation-and-death-by-79">Medicines and Healthcare products Regulatory Agency</a> in 2021.</p>
<h2>So what’s changed?</h2>
<p>A key challenge that comes with using monoclonal antibodies to manage SARS-CoV-2 infections is that they only bind to a single region of the spike protein. As the virus evolves, this region of the protein that the antibodies recognise can be altered by mutations. So it’s not entirely surprising that <a href="https://www.nejm.org/doi/full/10.1056/NEJMc2201933">lab studies</a> suggest the emergence of omicron <a href="https://www.bmj.com/content/377/bmj.o1009">has diminished</a> sotrovimab’s efficacy.</p>
<p>Casirivimab-imdevimab combines two monoclonal antibodies, thereby targeting two different regions of the spike protein, to try to overcome the speed at which SARS-CoV-2 can change. But this combination has proven ineffective in preventing omicron infection in <a href="https://www.nejm.org/doi/full/10.1056/NEJMc2119407">lab experiments</a>, leading the WHO to change its advice.</p>
<figure class="align-center ">
<img alt="An illustration of SARS-CoV-2, the coronavirus that causes COVID-19." src="https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485105/original/file-20220916-1645-dvps04.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Antibody drugs work by binding to the spike protein of SARS-CoV-2, neutralising the virus’s ability to infect our cells.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/neutralize-sarscov2-by-binding-protein-blocking-1941307918">Design_Cells/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Evidence will evolve alongside the virus</h2>
<p>Regulatory agencies and the WHO keep a close eye on the way existing treatments respond to emerging variants, and issue prescribing recommendations accordingly. </p>
<p>For drugs such as remdesivir that have a modest impact in certain groups of patients, the WHO issues conditional recommendations. Drugs that continue to work consistently receive strong recommendations, but these are also subject to review as the virus evolves.</p>
<p>While it might seem alarming that the WHO has changed its mind on these two antibody treatments, it’s actually a sign that the scientific process is working as it should.</p>
<p>This is now the 12th iteration of the <a href="https://www.bmj.com/content/370/bmj.m3379.long">WHO living guideline</a>, and the advice on the provision of COVID treatments is likely to continue to be updated as the pandemic plays out.</p>
<h2>Who will be most affected?</h2>
<p>In the fight against infection, we are not all equal. Vaccination has significantly reduced the risk of severe COVID for the vast majority of the population. However, some people are born with deficient immune systems or receive treatments that weaken their immune responses later in life, for example after receiving an organ transplant or chemotherapy. Certain infections or chronic diseases can further damage the immune system, which also naturally weakens with age. </p>
<p>One of the most common forms of immune deficiency is an inability to produce enough antibodies following vaccination or infection. So antibody therapies, which seek to supplement or replace those antibodies <a href="http://www.immunodeficiencyuk.org/whatarepids/treatment/immunoglobulinreplacementtherapy">artificially</a>, stand to benefit many people who are immunocompromised in particular.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-who-recommends-two-new-treatments-heres-how-they-work-175004">COVID: WHO recommends two new treatments – here's how they work</a>
</strong>
</em>
</p>
<hr>
<p>While guaranteeing monoclonal antibodies remain effective against a rapidly changing virus is an enormous challenge, this isn’t necessarily the end of this type of treatment for COVID. Next-generation monoclonal antibodies that better neutralise omicron subvariants may well be identified, although these too are unlikely to remain effective for long.</p>
<p>For the immunocompromised, but also for the wider public, there is an ongoing need for continued research into, and access to, effective COVID treatments – antivirals, antibodies and otherwise.</p>
<p>Unfortunately, when dealing with <a href="https://www.sciencedirect.com/topics/neuroscience/rna-viruses">RNA viruses</a>, mutations can rapidly bring down our defences. To prolong efficacy, combination treatments will be an important way forward compared with single-agent therapies.</p><img src="https://counter.theconversation.com/content/190787/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Zania Stamataki receives funding from the Medical Research Foundation, Innovate UK and BCHRF and she shares a PhD student with AstraZeneca on an iCASE MRC UKRI studentship unrelated to the article topic.
</span></em></p><p class="fine-print"><em><span>Adrian Shields receives funding from Association of Clinical Biochemistry and Laboratory Medicine and is a co-investigator on the UKRI/MRC funded COV-AD study. </span></em></p>This guidance replaces previous conditional recommendations for the use of these drugs and is based on emerging evidence that they’re not likely to work against omicron.Zania Stamataki, Associate Professor in Viral Immunology, University of BirminghamAdrian Shields, Associate Professor in Clinical Immunology, University of Birmingham, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1899392022-09-13T15:34:33Z2022-09-13T15:34:33ZAnother new COVID variant is spreading – here’s what we know about omicron BA.4.6<figure><img src="https://images.theconversation.com/files/484064/original/file-20220912-16-heeryv.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C4848%2C2714&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/chinese-coronavirus-covid19-under-microscope-3d-1640566693">Andrii Vodolazhskyi/Shutterstock</a></span></figcaption></figure><p>BA.4.6, a subvariant of the omicron COVID variant which has been quickly gaining traction <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">in the US</a>, is now confirmed to be spreading <a href="https://www.gov.uk/government/publications/investigation-of-sars-cov-2-variants-technical-briefings">in the UK</a>. </p>
<p>The <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1103869/Technical-Briefing-45-9September2022.pdf">latest briefing document</a> on COVID variants from the UK Health Security Agency (UKHSA) noted that during the week beginning August 14, BA.4.6 accounted for 3.3% of samples in the UK. It has since grown to make up around 9% of sequenced cases.</p>
<p>Similarly, according to the Centers for Disease Control and Prevention, BA.4.6 now accounts for <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">more than 9%</a> of recent cases across the US. The variant has also been identified in <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1103869/Technical-Briefing-45-9September2022.pdf">several other countries</a> around the world.</p>
<p>So what do we know about BA.4.6, and should we be worried? Let’s take a look at the information we have so far. </p>
<p>BA.4.6 is a descendant of the BA.4 variant of omicron. BA.4 was <a href="https://www.gavi.org/vaccineswork/five-things-weve-learned-about-ba4-and-ba5-omicron-variants">first detected</a> in January 2022 <a href="https://www.nature.com/articles/s41591-022-01911-2">in South Africa</a> and has since spread <a href="https://uk.news.yahoo.com/world-health-organization-covid-coronavirus-cases-150442006.html?guccounter=1">around the world</a> alongside the <a href="https://www.nature.com/articles/d41586-022-01730-y">BA.5 variant</a>.</p>
<p>It is not entirely clear how BA.4.6 has emerged, but it’s possible it could be a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8843165/">recombinant variant</a>. Recombination happens when two different variants of SARS-CoV-2 (the virus that causes COVID-19) infect the same person, at the same time. </p>
<p>While BA.4.6 will be similar to BA.4 in many ways, it carries a mutation to the spike protein, a protein on the surface of the virus which allows it to enter our cells. This mutation, R346T, has been seen <a href="https://www.thedailybeast.com/new-ba46-covid-variant-is-shaping-up-to-be-a-deja-vu-nightmare">in other variants</a> and is associated with <a href="https://www.biorxiv.org/content/10.1101/2022.08.09.503384v1">immune evasion</a>, meaning it helps the virus to escape antibodies acquired from vaccination and prior infection.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-vaccine-how-the-new-bivalent-booster-will-target-omicron-188840">COVID vaccine: how the new 'bivalent' booster will target omicron</a>
</strong>
</em>
</p>
<hr>
<h2>Severity, infectiousness and immune evasion</h2>
<p>Fortunately, omicron infections generally cause less serious illness, and we’ve seen <a href="https://pubmed.ncbi.nlm.nih.gov/35639835/">fewer deaths</a> with omicron than with earlier variants. We would expect this to apply to BA.4.6 too. Indeed, there have been no reports yet that this variant is causing more severe symptoms. </p>
<p>But we also know that omicron subvariants tend to be <a href="https://www.bmj.com/content/375/bmj.n2943">more transmissible</a> than previous variants. BA.4.6 appears to be <a href="https://apnews.com/article/covid-science-health-pandemics-flu-c92b8653683afbac3d81eebff8f5d29d">even better</a> at evading the immune system than BA.5, the currently dominant variant. Although this information is based on <a href="https://www.biorxiv.org/content/10.1101/2022.08.09.503384v1">a preprint</a> (a study that is yet to be peer-reviewed), other emerging data supports this. </p>
<p>According to <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1103869/Technical-Briefing-45-9September2022.pdf">the UKHSA’s briefing</a>, early estimates suggest BA.4.6 has a 6.55% relative fitness advantage over BA.5 in England. This indicates that BA.4.6 replicates more quickly in the early stages of infection and has a higher growth rate than BA.5. </p>
<p>The relative fitness advantage of BA.4.6 is <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1103869/Technical-Briefing-45-9September2022.pdf">considerably smaller</a> than that of BA.5 over BA.2, which was 45% to 55%.</p>
<figure class="align-center ">
<img alt="A woman receives a vaccination." src="https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484066/original/file-20220912-24-hxrko5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We’re still learning about how BA.4.6 might respond to COVID vaccines.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/doctor-holding-syringe-using-cotton-before-1864165381">BaLL LunLa/Shutterstock</a></span>
</figcaption>
</figure>
<p>The University of Oxford <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1103869/Technical-Briefing-45-9September2022.pdf">has reported</a> that people who had received three doses of Pfizer’s original COVID vaccine produce fewer antibodies in response to BA.4.6 than to BA.4 or BA.5. This is worrying because it suggests that COVID vaccines might be less effective against BA.4.6.</p>
<p>The capacity of BA.4.6 to evade immunity may however be addressed to a degree by the new <a href="https://theconversation.com/covid-vaccine-how-the-new-bivalent-booster-will-target-omicron-188840">bivalent boosters</a>, which target omicron specifically, alongside the original strain of SARS-CoV-2. Time will tell. </p>
<p>Meanwhile, one <a href="https://www.biorxiv.org/content/10.1101/2022.09.05.506628v1">preprint study</a> shows that BA.4.6 evades protection from <a href="https://edition.cnn.com/2022/09/07/health/evusheld-antibodies-omicron-ba-4-6/index.html">Evusheld</a>, an antibody therapy designed to protect people who are immunocompromised and <a href="https://www.gov.uk/government/news/evusheld-approved-to-prevent-covid-19-in-people-whose-immune-response-is-poor">don’t respond as well</a> to COVID vaccines.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-vaccine-how-the-new-bivalent-booster-will-target-omicron-188840">COVID vaccine: how the new 'bivalent' booster will target omicron</a>
</strong>
</em>
</p>
<hr>
<h2>Vaccination is key</h2>
<p>The emergence of BA.4.6 and other new variants is concerning. It shows the virus is still very much with us, and is mutating to find new ways to overcome our immune response from <a href="https://www.medrxiv.org/content/10.1101/2022.01.30.22270133v2">vaccination</a> and previous infections.</p>
<p>We know people who have had COVID previously can contract the virus <a href="https://journals.lww.com/jfmpc/Fulltext/2022/01000/Reinfection_with_SARS_CoV_2__An_inconvenient.63.aspx">again</a>, and this has been particularly true of omicron. In <a href="https://theconversation.com/covid-reinfections-could-be-more-severe-for-some-but-overall-evidence-doesnt-give-us-cause-for-concern-185732">some cases</a>, subsequent episodes can be worse.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/centaurus-what-we-know-about-the-new-covid-variant-and-why-theres-no-cause-for-alarm-187243">Centaurus: what we know about the new COVID variant and why there's no cause for alarm</a>
</strong>
</em>
</p>
<hr>
<p>But vaccination continues to offer good protection against severe disease, and is still the best weapon we have to fight COVID. The recent approval of bivalent boosters is good news. Beyond this, developing <a href="https://pubmed.ncbi.nlm.nih.gov/35838949/">multivalent coronavirus vaccines</a> that target multiple variants could provide even more durable protection.</p>
<p>A <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8825346/">recent study</a> showed that a multivalent coronavirus vaccine administered through the nose elicited a strong immune response against the original strain of SARS-CoV-2, as well as two variants of concern, in mouse models. </p>
<p>Close monitoring of new variants including BA.4.6 is pressing, as they could lead to the next wave of COVID pandemic. For the public, it will pay to stay cautious, and comply with any public health measures in place to prevent the spread of what remains a very contagious virus.</p><img src="https://counter.theconversation.com/content/189939/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Manal Mohammed does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>BA.4.6 seems to be even better at evading our immune response than BA.5.Manal Mohammed, Senior Lecturer, Medical Microbiology, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1872722022-08-30T12:19:19Z2022-08-30T12:19:19ZLow vaccine booster rates are now a key factor in COVID-19 deaths – and racial disparities in booster rates persist<figure><img src="https://images.theconversation.com/files/480642/original/file-20220823-11-gs3akm.jpg?ixlib=rb-1.1.0&rect=77%2C0%2C8660%2C5691&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As of August 2022, COVID-19 vaccination rates in Black and Hispanic people exceeded those of white Americans nationally, but only for the initial shots.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/getting-vaccinated-royalty-free-image/1363894755?adppopup=true">FatCamera/E+ via Getty Images</a></span></figcaption></figure><p>More than 450 people are <a href="https://www.nytimes.com/interactive/2021/us/covid-cases.html">dying of COVID-19 in the U.S. each day</a> as of late August 2022.</p>
<p>When COVID-19 vaccines first became available, public officials, community organizations and policymakers mobilized to get shots into arms. These efforts included <a href="https://www.cdc.gov/coronavirus/2019-ncov/community/health-equity/vaccine-equity.html">significant investments</a> in making vaccines accessible to <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2021/03/25/fact-sheet-biden-administration-announces-historic-10-billion-investment-to-expand-access-to-covid-19-vaccines-and-build-vaccine-confidence-in-hardest-hit-and-highest-risk-communities/">Black, Hispanic, American Indian and Alaska Native populations</a>. These groups experienced exceptionally high <a href="https://www.cdc.gov/mmwr/volumes/71/wr/mm7117e2.htm">COVID-19 death rates early in the pandemic</a> and had <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7006e3.htm?s_cid=mm7006e3_w">low initial vaccine rates</a>.</p>
<p>The <a href="https://www.cdc.gov/mmwr/volumes/71/wr/mm7123a2.htm">efforts worked</a>. As of August 2022, vaccination rates for the <a href="https://covid.cdc.gov/covid-data-tracker/#vaccination-demographics-trends">primary series – or required initial doses of COVID-19 vaccines – for Black and Hispanic people</a> exceeded those of white Americans.</p>
<p>But boosters are a different story. Comparable booster vaccine promotion efforts <a href="https://theconversation.com/should-you-get-a-covid-19-booster-shot-now-or-wait-until-fall-two-immunologists-help-weigh-the-options-184809">have been lacking</a>. <a href="https://www.theatlantic.com/health/archive/2022/04/cdc-covid-vaccine-booster-campaign/629536/">Confusion</a> in the public health messaging surrounding boosters and <a href="https://www.theguardian.com/us-news/2022/mar/27/us-second-covid-booster-delays-funding">limited federal funding</a> for rolling out vaccination campaigns have resulted in <a href="https://www.washingtonpost.com/politics/2022/04/18/us-booster-gap/">slow booster uptake</a> across the country. </p>
<p>As a result, divides have once again emerged. A recent <a href="https://doi.org/10.1001/jamanetworkopen.2022.27680">study of COVID-19 booster rates</a> found that 45% of white adults and 52% of Asian American adults had received boosters by January 2022. But only 29% of Black adults and 31% of adults who reported another racial or ethnic identity, such as American Indian, Alaska Native, Native Hawaiian, Pacific Islander or multiracial, were boosted. </p>
<p>As of late August 2022, the U.S. <a href="https://covid.cdc.gov/covid-data-tracker/#vaccination-demographics-trends">Centers for Disease Control and Prevention reported</a> that 36.3% of white adults in the U.S. 50 years or older and eligible for a second booster shot had received one. This is compared to only 28.4% for the Black population, 31.3% for American Indian or Alaska Native populations, and 25.1% for the Hispanic population. </p>
<p>New boosters aimed at the <a href="https://www.nytimes.com/article/covid-omicron-booster.html?">currently dominant omicron subvariant</a> are expected to become available <a href="https://www.nytimes.com/2022/08/23/us/politics/covid-booster-shots-biden.html">in early September 2022</a>. But the benefits of this new booster will be limited if it is not widely used. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/rRyIDCo0-Rc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The new variant-specific boosters are expected to be available in September 2022.</span></figcaption>
</figure>
<h2>Booster rates predict mortality rates across counties</h2>
<p>We are a team of population health researchers at <a href="https://www.bu.edu/sph/profile/andrew-stokes/">Boston University</a> and the <a href="https://cla.umn.edu/about/directory/profile/ewf">University of Minnesota</a>. We have been <a href="https://doi.org/10.1371/journal.pmed.1003571">tracking COVID-19 mortality rates</a> since the <a href="https://doi.org/10.1177%2F2378023120980918">beginning of the pandemic</a>. Our team uses demographic methods to identify social and structural factors that influence health and <a href="https://ajph.aphapublications.org/doi/full/10.2105/AJPH.2021.306331">contribute to evidence-based reforms</a> of <a href="https://thehill.com/opinion/healthcare/3572982-hidden-covid-fatalities-show-us-death-investigations-need-reform/">public health and health care systems</a>.</p>
<p>Vaccine studies suggest that adults age 50 and older who receive a booster shot have <a href="https://doi.org/10.1056/NEJMoa2115624">90% lower death rates</a> from COVID-19 than those who receive only the initial vaccine regimen. But the extent to which boosters have translated into health gains at the population level remains unclear. </p>
<p>Preliminary analyses by our team indicate that people in the U.S. living in counties with low booster uptake are dying from COVID-19 at higher rates than people living in counties with high booster uptake. In particular, in comparing the counties in the bottom 10% of booster rates with those in the top 10%, the COVID-19 death rates for residents of the bottom 10% of counties were 64% higher. Our analysis applies to the period from January to June 2022. It also adjusts for residents’ ages.</p>
<p>This difference in death rates may in part reflect the fact that counties with greater booster protection also tend to have higher rates of primary-series vaccination. Nonetheless, these findings suggest that at the population level, booster rates are now a key factor behind COVID-19 deaths. </p>
<p><iframe id="oENt5" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/oENt5/14/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>A prior study found that vaccination strategies that target high-risk geographical areas <a href="https://doi.org/10.1126/sciadv.abj2099">save more lives than strategies based on age alone</a>. Thus, the evidence suggests that limited federal funding for COVID-19 booster promotion should be sent to geographical areas that are currently reporting high rates of COVID-19 deaths. </p>
<h2>Learning from the community</h2>
<p>An effective booster campaign could build on lessons learned from prior vaccination campaigns. Specifically, this involves <a href="https://time.com/6204470/innovation-covid-19/">bringing vaccines directly to people</a>. From the earliest days of vaccine distribution during the pandemic, partnerships with faith-based organizations, housing communities and trusted community organizations have been <a href="https://doi.org/10.1007%2Fs11524-021-00594-3">successful in reaching populations with low vaccination rates</a>. </p>
<p>Other strategies to make boosters <a href="https://www.cdc.gov/vaccines/covid-19/downloads/vaccination-strategies.pdf">more accessible</a> include increasing access to vaccine centers via public transit and outside of typical working hours. In rural areas, <a href="https://doi.org/10.1093%2Fofid%2Fofab152">evidence-based strategies</a> to promote vaccination include education of community ambassadors, use of social media and operation of mobile vaccination sites. </p>
<p>In the absence of federal funding, community efforts have aimed to make boosters more accessible. A New Yorker documentary filmed in 2021 explored the <a href="https://www.newyorker.com/culture/the-new-yorker-documentary/an-alabama-womans-neighborly-vaccination-campaign">challenges that one rural community in Alabama</a> – Panola – has faced with vaccination. It highlights community leader Dorothy Oliver as she promotes vaccination with little to no support from the government. Her efforts included door-to-door campaigns, discussions with residents about their fears and concerns and coordination of vaccination logistics, including scheduling and transport. </p>
<p>In a similar way, Minneapolis’ Seward Vaccine Equity Project <a href="https://www.healthaffairs.org/do/10.1377/forefront.20220518.186581/">increased booster shots among East African immigrant families</a> by having volunteers call members of their own communities and offer them a booster appointment and a ride. The volunteers were also available to answer residents’ questions and address any concerns. Successful efforts like those could be carried out by health departments on a much wider scale.</p><img src="https://counter.theconversation.com/content/187272/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Stokes receives funding from the Robert Wood Johnson Foundation, the W.K. Kellogg Foundation, and the National Institute on Aging. </span></em></p><p class="fine-print"><em><span>Elizabeth Wrigley-Field is a member of the Seward Vaccine Equity Project, discussed in the article. She receives funding from the Eunice Kennedy Shriver National Institute on Child Health and Human Development via the Minnesota Population Center and from the National Institute on Aging via the Life Course Center, both at the University of Minnesota.</span></em></p><p class="fine-print"><em><span>Dielle Lundberg and Rafeya Raquib do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Early on, public health messaging focused on the need for vaccines to combat COVID-19. But far less attention has been given to the role of boosters in preventing deaths and reducing inequities.Andrew Stokes, Assistant Professor of Global Health, Boston UniversityDielle Lundberg, Research Fellow in Global Health, Boston UniversityElizabeth Wrigley-Field, Assistant Professor of Sociology, University of MinnesotaRafeya Raquib, Research Fellow in Global Health, Boston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1888402022-08-17T15:56:44Z2022-08-17T15:56:44ZCOVID vaccine: how the new ‘bivalent’ booster will target omicron<figure><img src="https://images.theconversation.com/files/479448/original/file-20220816-8398-z5eua.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6303%2C4189&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/male-doctor-holding-syringe-making-covid-2049512780">Prostock-studio/Shutterstock</a></span></figcaption></figure><p>The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) <a href="https://www.gov.uk/government/news/first-bivalent-covid-19-booster-vaccine-approved-by-uk-medicines-regulator">has approved</a> a bivalent COVID booster vaccine, making it <a href="https://www.bbc.co.uk/news/health-62548336">the first country</a> in the world to do so. </p>
<p>Developed by Moderna, this vaccine has been approved for use in adults, and is set to form part of the upcoming <a href="https://www.gov.uk/government/news/jcvi-publishes-advice-on-covid-19-vaccines-for-autumn-booster-programme">autumn booster campaign</a> in the UK.</p>
<p>But what actually is a bivalent vaccine, and what impact might this booster have on the trajectory of the pandemic? Let’s take a look.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-vaccines-our-current-shots-could-soon-be-updated-to-target-new-variants-an-immunology-expert-explains-185920">COVID vaccines: our current shots could soon be updated to target new variants – an immunology expert explains</a>
</strong>
</em>
</p>
<hr>
<p>The COVID vaccines and boosters we currently have, or the first generation, are “monovalent” vaccines. This means they only target the original strain of SARS-CoV-2 (the virus that causes COVID-19). </p>
<p>A recent study suggested that first generation COVID vaccines prevented <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099%2822%2900320-6/fulltext">up to 20 million deaths</a> around the world in their first year of use. </p>
<p>The emergence of the new variants of SARS-CoV-2, including <a href="https://pubmed.ncbi.nlm.nih.gov/34989238/">omicron variants</a>, has been very concerning. Omicron variants are better than earlier non-omicron variants at evading our immunity from prior infections and vaccines.</p>
<p>Although the vaccines continue to offer protection against deaths and hospital admissions, <a href="https://pubmed.ncbi.nlm.nih.gov/35249272/">recent research</a> has shown the initial course of COVID vaccination provides limited protection against symptomatic disease caused by the omicron variant.</p>
<p>So this second-generation <a href="https://www.gov.uk/government/publications/regulatory-approval-of-spikevax-bivalent-originalomicron-booster-vaccine">bivalent</a> or dual-variant vaccine targets both the ancestral strain of SARS-CoV-2 and the omicron variant BA.1. It contains 25 micrograms of original coronavirus vaccine and 25 micrograms of vaccine that specifically targets the omicron variant.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1559151753492369409"}"></div></p>
<p>Likewise, “<a href="https://journals.asm.org/doi/10.1128/CVI.00298-16">multivalent</a>” vaccines can protect against even more than two strains of a microbe – though we don’t have any multivalent shots for COVID yet.</p>
<p>Bivalent and multivalent vaccines aren’t new in healthcare. For example, all influenza vaccines available <a href="https://www.gov.uk/government/publications/influenza-vaccines-marketed-in-the-uk/all-influenza-vaccines-marketed-in-the-uk-for-the-2022-to-2023-season">in the UK</a> and <a href="https://www.cdc.gov/flu/prevent/quadrivalent.htm">the US</a> are quadrivalent, targeting four different strains of flu. </p>
<p>The Gardasil-9 vaccine targets nine strains of the <a href="https://www.cdc.gov/vaccines/vpd/hpv/public/index.html">human papillomavirus</a>, a common sexually transmitted infection. Meanwhile, the <a href="https://www.cdc.gov/vaccines/hcp/vis/vis-statements/ppv.html">pneumococcal polysaccharide vaccine</a>, PPSV23, targets an impressive 23 different strains of bacteria that cause pneumococcal diseases, protecting against pneumonia and meningitis, among others.</p>
<h2>Safety and efficacy</h2>
<p>No serious safety concerns have been identified for this new bivalent vaccine. Any <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1097996/Spikexax_bivalent_Original_Omicron_SmPC.pdf">side effects</a> observed during safety monitoring were broadly the same as those seen with the original <a href="https://www.cdc.gov/vaccines/covid-19/info-by-product/moderna/reactogenicity.html">Moderna booster dose</a>. These are typically mild and get better on their own, such as fever, headache, fatigue or pain at the injection site.</p>
<p>The MHRA’s approval of Moderna’s new bivalent vaccine is <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1097996/Spikexax_bivalent_Original_Omicron_SmPC.pdf">based on data</a> from a clinical trial involving more than 400 participants. The results showed that a booster of the bivalent vaccine triggers a strong immune response against both the original Wuhan strain and omicron BA.1.</p>
<p>Specifically, <a href="https://investors.modernatx.com/news/news-details/2022/Medicines-and-Healthcare-Products-Regulatory-Agency-MHRA-Authorizes-Modernas-Omicron-Containing-Bivalent-Booster-in-the-UK/default.aspx">Moderna reported</a> that in a combined phase 2 and 3 trial, a booster dose of the new bivalent vaccine increased neutralising antibody levels against omicron BA.1 roughly eight-fold above baseline levels. This was a superior neutralising antibody response when compared with the company’s current monovalent booster.</p>
<p>Notably, omicron BA.1 was the first omicron subvariant, but BA.5 is now the dominant variant <a href="https://www.gov.uk/government/news/covid-19-variants-identified-in-the-uk-latest-updates">in the UK</a> and globally. While this vaccine was designed to target BA.1, Moderna have stated the booster also elicited potent neutralising antibody responses <a href="https://investors.modernatx.com/news/news-details/2022/Medicines-and-Healthcare-Products-Regulatory-Agency-MHRA-Authorizes-Modernas-Omicron-Containing-Bivalent-Booster-in-the-UK/default.aspx">against BA.4 and BA.5</a> compared with the company’s current booster.</p>
<p>These results are promising, but we will need to watch closely for confirmation that they translate beyond clinical trials, and that the vaccine is effective against BA.5 and potentially any new variants in the real word.</p>
<figure class="align-center ">
<img alt="An illustration of SARS-CoV-2, the coronavirus that causes COVID-19." src="https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479452/original/file-20220816-10908-6gzsyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The new bivalent vaccine targets omicron as well as the ancestral strain of SARS-CoV-2.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/corona-virus-sarscov2-novel-coronavirus-concept-1699701805">creativeneko/Shutterstock</a></span>
</figcaption>
</figure>
<p>In the meantime, Moderna has completed <a href="https://investors.modernatx.com/news/news-details/2022/Medicines-and-Healthcare-Products-Regulatory-Agency-MHRA-Authorizes-Modernas-Omicron-Containing-Bivalent-Booster-in-the-UK/default.aspx">regulatory submissions</a> for its bivalent vaccine in other countries including Canada, Australia and the European Union. Pending authorisation, the vaccine is likely to be available <a href="https://abcnews.go.com/Health/covid-bivalent-vaccine-expected-us-fall/story?id=88441908">in the US</a> starting in autumn too.</p>
<p>Other pharmaceutical companies including <a href="https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-omicron-adapted-covid-19">Pfizer and BioNTech</a> are also developing and trialling bivalent boosters to target omicron.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-vaccines-why-second-boosters-are-being-offered-to-vulnerable-people-in-the-uk-but-not-young-and-healthy-people-yet-180215">COVID vaccines: why second boosters are being offered to vulnerable people in the UK – but not young and healthy people yet</a>
</strong>
</em>
</p>
<hr>
<h2>Boosters are a vital weapon against COVID</h2>
<p>When immunity from initial vaccine doses wanes, boosters are an important way to increase our immunity. And there’s little doubt that introducing this new Moderna bivalent vaccine will provide substantial protection to many people against COVID, including the newer variants, as we enter the winter months.</p>
<p>At the same time, first-generation boosters are still highly valuable, alongside other precautions we can continue taking to prevent the spread of the virus and new variants. These might include wearing a mask in crowded places, staying away from others when ill, and maintaining good hand hygiene. </p>
<p>COVID remains a threat and we can’t anticipate how the virus will evolve. We may well see the emergence of new variants, creating a need for multivalent vaccines in the future.</p><img src="https://counter.theconversation.com/content/188840/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Manal Mohammed does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The UK has become the first country to approve the shot, which targets omicron alongside the original strain of SARS-CoV-2.Manal Mohammed, Senior Lecturer, Medical Microbiology, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1868262022-07-27T04:13:58Z2022-07-27T04:13:58ZNew COVID variants may be more transmissible but that doesn’t mean the R0 – or basic reproduction number – has increased<p>During the pandemic we have all become familiar with a lot of epidemiological concepts. </p>
<p>One that was introduced to us early in 2020 is the “basic reproductive number”, or R0. This tells us about the intrinsic contagiousness of a virus, or its inherent capacity to be spread from one person to another in a particular population. </p>
<p>We also learned about the “effective reproductive number”, or Reff. This tells us about the rate at which a virus is actually spreading through that population.</p>
<p>With the emergence of BA.4/5, there has been some confusion around how these concepts help us to understand why one variant spreads faster than another. </p>
<p>Just because a variant spreads faster, it doesn’t necessarily mean it has a higher R0.</p>
<h2>What does the R0 actually tell us?</h2>
<p>R0 tells us about the number of secondary cases arising from a single case in a fully susceptible population. It describes the potential capacity of a pathogen (such as a virus) to spread, and is pathogen-specific. </p>
<p>Pathogens with higher R0 values have the potential to cause larger epidemics. For ancestral strains of SARS-CoV-2 (the virus that causes COVID), R0 was <a href="https://doi.org/10.1371/journal.pone.0242128">estimated to be around 3</a>. </p>
<p>R0 is also population-specific. It depends on the population’s behaviour at “baseline”, before the pandemic. For example, a densely populated city with lots of indoor venues in which people mix is likely to have a higher R0 for the same pathogen than a region with a sparse population and less mixing between groups.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/r0-how-scientists-quantify-the-intensity-of-an-outbreak-like-coronavirus-and-predict-the-pandemics-spread-130777">R0: How scientists quantify the intensity of an outbreak like coronavirus and predict the pandemic's spread</a>
</strong>
</em>
</p>
<hr>
<h2>What about the Reff?</h2>
<p>The Reff is the average number of new infections caused by an infected individual in the presence of public health measures, behavioural change, and population immunity (from previous infection and vaccination). </p>
<p>The Reff will therefore change over time.</p>
<p>It is a <a href="https://epiforecasts.io/">key indicator</a> of whether an epidemic is growing or shrinking. When the Reff is above 1, the epidemic is growing. If control measures, population immunity, or other factors can bring the Reff below 1, the epidemic is in decline.</p>
<p>Throughout the pandemic, the Reff has been routinely estimated for Australia and <a href="https://www.health.gov.au/resources/publications/australian-national-disease-surveillance-plan-for-covid-19">reported</a> to decision-makers.</p>
<h2>How do new variants out-compete existing ones?</h2>
<p>The COVID pandemic can be divided into several distinct eras, each defined by the emergence of a new variant: </p>
<ul>
<li>Alpha in late 2020</li>
<li>Delta in mid-2021</li>
<li>Omicron BA.1 in late 2021</li>
<li>Omicron BA.2 in early 2022</li>
<li>and now Omicron BA.4 and BA.5. </li>
</ul>
<p>Each of these variants was able to outcompete and replace the one before it.</p>
<p>If we observe that a hypothetical “variant A” is spreading through a population faster than “variant B”, we say that variant A has a “growth advantage” over variant B. </p>
<p>This growth advantage, if sustained, means variant A will replace variant B as the new dominant variant spreading in the population. </p>
<p>A variant can have a growth advantage and not actually be intrinsically more transmissible. In fact, the R0 of variant A may be higher, lower, or the same as variant B.</p>
<p>This is because the growth advantage of variant A, compared to variant B, may be driven by any combination of:</p>
<ol>
<li>a shorter generation time</li>
<li>increased intrinsic transmissibility (R0)</li>
<li>an increased level of “immune evasion”.</li>
</ol>
<p>Each of these drivers has a different impact on the future epidemic trajectory and implications for the effectiveness of control measures.</p>
<p><strong>Shorter generation time</strong></p>
<p>A shorter generation time means a shorter time, on average, between a person becoming infected and then infecting another person. The average number of new infections arising from each infected person is the same for both variants, but those infections happen more quickly for variant A. This will lead to a more rapid rise in cases of variant A, even when R0 is the same.</p>
<p><strong>Intrinsic transmissibility</strong></p>
<p>Increased intrinsic transmissibility refers to the situation where the R0 of variant A is higher than that of variant B. Multiple different biological changes to the virus, such as changes that increase the infectiousness of an infected person, may drive this.</p>
<p><strong>Immune evasion</strong></p>
<p>Immune evasion refers to how easily a variant infects people who have previously been infected and or vaccinated.</p>
<p>Variants with very high levels of immune evasion can spread quickly in highly immune populations because there are simply more people in the population who are able to be infected. But it doesn’t mean they are intrinsically more transmissible.</p>
<p>In fact, they may even have a reduced R0 and still have a growth advantage.</p>
<p><strong>Implications for Reff</strong></p>
<p>All three of these mechanisms can result in a growth advantage, but have different implications for the Reff of variant A compared to variant B.</p>
<p>An increase in intrinsic transmissibility or immune escape will lead to an increased Reff for variant A compared to variant B. However a shorter generation time can lead to a growth advantage without affecting the Reff. If variant A has only a shorter generation time, it will spread faster through the population than variant B.</p>
<h2>How has this played out in the COVID pandemic?</h2>
<p>Over the course of the COVID pandemic, several variants have emerged with considerable growth advantage over previous variants: Alpha, then Delta, Omicron BA.1 and BA.2, and most recently, Omicron BA.4 and BA.5. </p>
<p>The reasons for the growth advantage over previous variants have been driven by different factors.</p>
<p>Alpha’s growth advantage over ancestral strains was estimated to be due to higher intrinsic transmissibility. Scientists <a href="https://pubmed.ncbi.nlm.nih.gov/33658326/">estimated</a> the basic reproduction number (R0) of Alpha was 43–90% higher than for ancestral strains. </p>
<p>When Omicron BA.1 rapidly emerged in late 2021 in highly immune populations (including Australia, where most <a href="https://www.abc.net.au/news/2021-03-02/charting-australias-covid-vaccine-rollout/13197518">jurisdictions</a> had achieved more than 85% second-dose vaccine coverage in eligible groups), scientists immediately suspected <a href="https://twitter.com/trvrb/status/1466076797670363140">immune evasion was playing a role</a>.</p>
<p><a href="https://twitter.com/_nickgolding_/status/1468226234995773443?s=12">Analyses of emerging data</a> quantified the relative contribution of immune evasion and intrinsic transmissibility that could explain the rapid spread.</p>
<p>Most recently, we have seen the rapid rise of Omicron BA.4 and BA.5 globally. Emerging <a href="https://www.medrxiv.org/content/10.1101/2022.05.16.22275151v1">evidence</a> suggests <a href="https://www.biorxiv.org/content/10.1101/2022.05.26.493517v1">immune evasion</a> is, once again, likely a significant factor contributing to the <a href="https://www.medrxiv.org/content/10.1101/2022.04.29.22274477v1">transmission advantage</a> of BA.4 and BA.5 over previous Omicron variants.</p>
<p>This means we expect BA.4 and BA.5 to spread rapidly in Australia, despite our very high levels of vaccination coverage and lots of previous infection. </p>
<p>However, the R0 may not have <a href="https://theconversation.com/australia-is-heading-for-its-third-omicron-wave-heres-what-to-expect-from-ba-4-and-ba-5-185598">changed</a>. Even with the same intrinsic transmissibility, simply having more of the population being susceptible again, means the same R0 will end up translating to more infections. </p>
<h2>Not a simple calculation</h2>
<p>Throughout the pandemic, infectious disease epidemiologists have had to carefully evaluate the available data to estimate why a new variant has a growth advantage.</p>
<p>Others, including some scientists <a href="https://theconversation.com/australia-is-heading-for-its-third-omicron-wave-heres-what-to-expect-from-ba-4-and-ba-5-185598">on The Conversation</a>, have unfortunately simply assumed that the growth advantage is due to an increased intrinsic transmissibility.</p>
<p>They have done this by multiplying the R0 of an existing variant by how much faster a new variant is estimated to be spreading. Repeated application of this approach has resulted in an inflated R0 estimate for BA.4/5, <a href="https://theconversation.com/why-we-corrected-our-estimates-for-the-reproduction-number-of-two-covid-subvariants-187624">similar to that of measles</a>.</p>
<p>While this approach was <a href="https://pubmed.ncbi.nlm.nih.gov/33658326/">OK for Alpha</a>, because household studies showed that the variant spread more efficiently in previously unexposed populations, it was not appropriate once Omicron appeared.</p>
<p>None of these considerations are unique to COVID. For example, new influenza variants mostly arise due to <a href="https://www.antigenic-cartography.org">immune escape</a>, driving a growth advantage and replacement of the previously circulating strain.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-is-heading-for-its-third-omicron-wave-heres-what-to-expect-from-ba-4-and-ba-5-185598">Australia is heading for its third Omicron wave. Here's what to expect from BA.4 and BA.5</a>
</strong>
</em>
</p>
<hr>
<h2>So what is the R0 of BA.4/5?</h2>
<p>With the emergence of each new variant, the task has become more challenging as the population’s infection history (whether you’ve been infected before, when and how many times) makes interpretation of the data more and more difficult.</p>
<p>And so it is now very difficult to estimate the R0 for BA.4/5.</p>
<p>It is certainly higher than for Alpha and Delta, with the <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1005395/23_July_2021_Risk_assessment_for_SARS-CoV-2_variant_Delta.pdf">weight of evidence</a> indicating a value at least double that of the ancestral variant (3). That would make it around 6.</p>
<p>And it is likely higher still because Omicron BA.1 out-competed Delta due to both an <a href="https://twitter.com/_nickgolding_/status/1468226234995773443?s=12">increase in intrinsic transmissibility and immune escape</a>.</p>
<p>We don’t yet fully understand why BA.2 replaced BA.1, with both <a href="https://doi.org/10.1101/2022.01.28.22270044">intrinsic transmissibility and immune escape potentially contributing</a>. But we do know that immune evasion is sufficient to explain the observed growth advantage of BA.4/5 over BA.2.</p>
<p>Therefore, our current best estimate for the R0 for BA.4/5 is that it is likely similar to that for BA.2, but the actual value remains uncertain. It is likely in the range of 6-10.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-we-corrected-our-estimates-for-the-reproduction-number-of-two-covid-subvariants-187624">Why we corrected our estimates for the reproduction number of two COVID subvariants</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/186826/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Freya Shearer receives funding from the National Health and Medical Research Council, the Australian Government Departments of Health and Foreign Affairs and Trade, and NSW Health. </span></em></p><p class="fine-print"><em><span>Catherine Bennett receives funding from Medical Research Future Find and the National Health and Medical Research Council. Catherine is also on the scientific advisory committee for Impact Health Technology and ResApp Healthcare Pty Ltd, and was an independent expert on the AstraZeneca COVID Vaccine Advisory Committee in 2021.</span></em></p><p class="fine-print"><em><span>James McCaw receives funding from the Australian Government Departments of Health and Foreign Affairs and Trade, the Australian Research Council and the National Health and Medical Research Council. He is an invited expert member of the Communicable Disease Network of Australia and between January 2020 and May 2022 was an invited expert member of the Australian Health Protection Principal Committee.</span></em></p><p class="fine-print"><em><span>Nick Golding receives funding from Australian, NSW, and WA Government Departments of Health, the Australian Research Council and the National Health and Medical Research Council. </span></em></p><p class="fine-print"><em><span>Hassan Vally does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Just because a variant spreads faster, it doesn’t necessarily mean it has a higher R0.Freya Shearer, Research Fellow, Epidemic Decision Support, The University of MelbourneCatherine Bennett, Chair in Epidemiology, Deakin UniversityHassan Vally, Associate Professor, Epidemiology, Deakin UniversityJames McCaw, Professor in Mathematical Biology, The University of MelbourneNick Golding, Honorary Research Fellow, Telethon Kids Institute, and Professor, Curtin School of Population Health, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1871322022-07-26T12:00:15Z2022-07-26T12:00:15ZHow the omicron subvariant BA.5 became a master of disguise – and what it means for the current COVID-19 surge<figure><img src="https://images.theconversation.com/files/475502/original/file-20220721-9531-a1zj6x.jpg?ixlib=rb-1.1.0&rect=0%2C3%2C2400%2C1591&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The new BA.5 subvariant has caused a sharp rise in cases and hospitalizations throughout much of the United States.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sustained-jumps-in-cases-and-hospitalizations-fueled-by-the-news-photo/1241906325?adppopup=true">Irfan Khan/Los Angeles Times via Getty Images</a></span></figcaption></figure><p>The omicron subvariant known as BA.5 was <a href="https://doi.org/10.1038/s41591-022-01911-2">first detected in South Africa</a> in February 2022 and spread rapidly throughout the world. As of the second week of July 2022, BA.5 constituted <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">nearly 80% of COVID-19 variants in the United States</a>.</p>
<p>Soon after researchers in South Africa reported the <a href="https://www.who.int/news/item/26-11-2021-classification-of-omicron-(b.1.1.529)-sars-cov-2-variant-of-concern">original version of the omicron variant (B.1.1.529)</a> on Nov. 24, 2021, many scientists – including me – speculated that if omicron’s numerous mutations made it either more transmissible or better at immune evasion than the preceding delta variant, <a href="https://theconversation.com/will-omicron-the-new-coronavirus-variant-of-concern-be-more-contagious-than-delta-a-virus-evolution-expert-explains-what-researchers-know-and-what-they-dont-169020">omicron could become the dominant variant around the world</a>. </p>
<p>The omicron variant did indeed become <a href="https://doi.org/10.1038/s41392-022-01105-9">dominant early in 2022</a>, and several sublineages, or subvariants, of omicron have since emerged: BA.1, BA.2, BA.4 and BA.5, among others. With the continued appearance of such highly transmissible variants, it is evident that SARS-CoV-2, the virus that causes COVID-19, is effectively using classic techniques that viruses use to escape the immune system. These escape strategies range from <a href="https://doi.org/10.1002/jmv.26597">changing the shape of key proteins</a> recognized by your immune system’s protective antibodies to <a href="https://doi.org/10.1038/s41467-020-17496-8">camouflaging its genetic material</a> to fool human cells into considering it a part of themselves instead of an invader to attack. </p>
<p>I am a <a href="https://vbs.psu.edu/directory/svk11">virologist</a> who studies emerging viruses and viruses that jumped from animals to humans, <a href="https://scholar.google.com/citations?user=dqahf8oAAAAJ&hl=en">such as SARS-CoV-2</a>. My research group has been tracking the transmission and evolution of SARS-CoV-2, evaluating changes in how well the omicron subvariants evade the immune system and the severity of disease they cause after infection.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/M3g4RXojkpc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The BA.5 subvariant is better able to evade the body’s immune system than previous subvariants.</span></figcaption>
</figure>
<h2>How is virus transmissibility in a population measured?</h2>
<p>The <a href="https://theconversation.com/r0-how-scientists-quantify-the-intensity-of-an-outbreak-like-coronavirus-and-predict-the-pandemics-spread-130777">basic reproduction number, R0</a> – pronounced “R-naught” – <a href="https://doi.org/10.5005/jp-journals-10071-23649">measures the transmissibility of a virus</a> in a yet-uninfected population.</p>
<p>Once a proportion of individuals in a population become immune due to prior infection or vaccination, epidemiologists use the term <a href="https://doi.org/10.1371/journal.pcbi.1008409">effective reproduction number</a>, called Re or Rt, to measure the transmissibility of the virus. The Re of the omicron variant has been estimated to be <a href="https://doi.org/10.1093/jtm/taac037">2.5 times higher</a> than the delta variant. This increased transmissibility most likely helped omicron out-compete delta to become the dominant variant. </p>
<p>The larger question, then, is what is driving the evolution of omicron sublineages? The answer to that is a well-known process called <a href="https://www.khanacademy.org/science/ap-biology/natural-selection/common-ancestry-and-continuing-evolution/a/evolution-of-viruses">natural selection</a>. Natural selection is an evolutionary process where traits that give a species a reproductive advantage continue to be passed down to the next generation, while traits that don’t are phased out through competition. As SARS-CoV-2 continues to circulate, natural selection will favor mutations that give the virus the greatest survival advantage.</p>
<h2>What makes omicron and its offshoots so stealthy at spreading?</h2>
<p>Several mechanisms contribute to the increased transmissibility of SARS-CoV-2 variants. One is the ability to <a href="https://doi.org/10.1016/S1473-3099(21)00262-0">bind more strongly to the ACE2 receptor</a>, a protein in the body that primarily helps regulate blood pressure but can also help SARS-CoV-2 enter cells. The more recent omicron sublineages have mutations that make them better at escaping antibody protection while retaining their ability to effectively bind to ACE2 receptors. The BA.5 sublineage can <a href="https://doi.org/10.1056/NEJMc2206576">evade antibodies</a> from both vaccination and prior infection. </p>
<p>Omicron sublineages BA.4 and BA.5 share several mutations with earlier omicron sublineages, but also have three unique mutations: <a href="https://doi.org/10.1038/s41586-022-04980-y">L452R, F486V</a> and reversion (or the lack of mutation) of <a href="https://doi.org/10.1038/s41586-022-05053-w">R493Q</a>. L452R and F486V in the spike protein help BA.5 escape antibodies. In addition, the L452R mutation helps the virus <a href="https://doi.org/10.1016/j.chom.2021.06.006">bind more effectively</a> to the membrane of its host cell, a crucial feature associated with COVID-19 disease severity.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Zfu1EwRE0WE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The BA.5 subvariant is responsible for two-thirds of all current COVID-19 cases in the United States.</span></figcaption>
</figure>
<p>While the other mutation in BA.5, F486V, may help the sublineage escape from certain types of antibodies, it could decrease its ability to bind to ACE2. Strikingly, BA.5 appears to compensate for decreased ACE2 binding strength through another mutation, R493Q reversion, that is thought to <a href="https://doi.org/10.1038/s41586-022-05053-w">restore its lost affinity for ACE2</a>. The ability to successfully escape immunity while maintaining its ability to bind to ACE2 may have potentially contributed to the rapid global spread of BA.5. </p>
<p>In addition to these immune-evading mutations, SARS-CoV-2 has been evolving to <a href="https://doi.org/10.1038/s41586-021-04352-y">suppress its hosts’ - in this case, humans’ – innate immunity</a>. Innate immunity is the body’s first line of defense against invading pathogens, comprised of antiviral proteins that help fight viruses. SARS-CoV-2 has the ability to suppress the activation of some of these key antiviral proteins, meaning it’s able to effectively get past many of the body’s defenses. This explains the spread of infections among vaccinated or previously infected people.</p>
<p>Innate immunity exerts a strong selective pressure on SARS-CoV-2. Delta and omicron, the two most recent and highly successful SARS-CoV-2 variants, <a href="https://doi.org/10.1038/s41586-021-04352-y">share several mutations</a> that could be key in helping the virus breach innate immunity. However, scientists do not yet fully understand what changes in BA.5 might allow it to do so. </p>
<h2>What’s next?</h2>
<p>BA.5 will not be the end game. As the virus continues to circulate, this evolutionary trend will likely lead to the emergence of more transmissible variants that are capable of immune escape. </p>
<p>While it is difficult to predict what variants will arrive next, we researchers cannot rule out the possibility that some of these variants could lead to increased disease severity and higher hospitalization rates. As the virus continues to evolve, most people will <a href="https://www.nytimes.com/2022/05/16/health/covid-reinfection.html">get COVID-19 multiple times</a> despite vaccination status. This could be confusing and frustrating for some, and may contribute to vaccine hesitancy. Therefore, it is essential to recognize that vaccines <a href="https://www.uptodate.com/contents/covid-19-vaccines">protect you from severe disease and death</a>, not necessarily from getting infected.</p>
<p>Research over the past two and a half years has helped scientists like me learn a lot about this new virus. However, many unanswered questions remain because the virus constantly evolves, and we are left trying to target a constantly moving goal post. While <a href="https://doi.org/10.1038/d41586-022-01771-3">updating vaccines</a> to match circulating variants is an option, it may not be practical in the short term because the virus evolves too quickly. Vaccines that <a href="https://doi.org/10.7554/eLife.70330">generate antibodies against a broad range of SARS-CoV-2 variants</a> and a cocktail of <a href="https://doi.org/10.1038/d41586-022-00562-0">broad-ranging treatments</a>, including monoclonal antibodies and antiviral drugs, will be critical in the fight against COVID-19.</p><img src="https://counter.theconversation.com/content/187132/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Suresh V. Kuchipudi receives funding from the National Institutes of Health, National Science Foundation and USDA-National Institute of food and Agriculture. </span></em></p>Face masks are still an effective way to help stop the spread of the BA.5 subvariant.Suresh V. Kuchipudi, Professor and Chair of Emerging Infectious Diseases, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1863942022-07-07T00:06:36Z2022-07-07T00:06:36ZA new Omicron wave is upon New Zealand, with older people now most at risk – here’s what to expect<figure><img src="https://images.theconversation.com/files/472898/original/file-20220706-27-wm8c6q.jpg?ixlib=rb-1.1.0&rect=48%2C126%2C6418%2C4052&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/Volurol</span></span></figcaption></figure><p>New Zealand has been in a COVID lull for the past two months, but with the BA.5 variant on the rise and more than 10,000 new daily cases <a href="https://www.health.govt.nz/news-media/news-items/10290-community-cases-522-hospitalisations-10-icu-12-deaths">reported this week</a>, it appears we are now at the start of a second Omicron wave. </p>
<p>How large it will be is difficult to predict, but a number of factors coincide to make this the most serious moment in the pandemic this year since the first wave in March. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1544503439618867200"}"></div></p>
<p>BA.5 is the <a href="https://www.nature.com/articles/d41586-022-01730-y">latest instalment in the Omicron series</a>. It was <a href="https://www.nature.com/articles/s41591-022-01911-2">first detected in South Africa</a> in February 2022 and is closely related to BA.2, the variant currently still dominant in New Zealand. </p>
<p>It carries distinct mutations in the spike protein, two of which are associated with higher transmissibility and immune evasion. The rise in BA.5 seems to stem from its ability to infect people who were immune to earlier variants, but so far there is no indication the variant causes more severe disease. </p>
<p>BA.5 was first detected in the New Zealand community in April and cases have been appearing consistently since May. It has quickly <a href="https://www.rnz.co.nz/news/in-depth/450874/covid-19-data-visualisations-nz-in-numbers">risen to 32%</a> of sequenced community cases and looks set to become the dominant variant in the next week. It already is dominant in <a href="https://covariants.org/per-country">other countries</a>. </p>
<p>Our <a href="https://www.covid19modelling.ac.nz/waning-of-immunity-and-re-infection-with-omicron/">recent modelling</a> showed a second wave of COVID this year was likely as a consequence of waning immunity, but the spread of BA.5 has hastened its arrival. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-there-so-many-new-omicron-sub-variants-like-ba-4-and-ba-5-will-i-be-reinfected-is-the-virus-mutating-faster-182274">Why are there so many new Omicron sub-variants, like BA.4 and BA.5? Will I be reinfected? Is the virus mutating faster?</a>
</strong>
</em>
</p>
<hr>
<h2>What to expect</h2>
<p>A big concern at the moment is that case numbers in older age groups are higher now than ever before. The March wave was heavily concentrated in younger people, with under 60s making up 91% of all cases up to the end of April. </p>
<p>That helped keep a lid on the hospitalisation rate and has built strong hybrid immunity, acquired from both infection and vaccination, in these groups. But it leaves a large susceptible population in older groups.</p>
<p>Part of BA.5’s advantage is a better ability to re-infect people who’ve had COVID before. Nevertheless, prior infection with a different variant does provide immunity, however imperfect, and those who haven’t been previously infected are at higher risk of catching the virus in the second wave. In New Zealand, this predominantly means older people. </p>
<iframe title="New daily case numbers in older age groups" aria-label="Interactive line chart" id="datawrapper-chart-3AhcP" src="https://datawrapper.dwcdn.net/3AhcP/2/" scrolling="no" frameborder="0" style="border: none;" width="100%" height="400"></iframe>
<p>Waning immunity means many people who are five to six months after their third vaccine dose will have significantly lower immunity now than they did in March.</p>
<p>And winter is flu season. The healthcare system is <a href="https://www.stuff.co.nz/national/health/129115645/northland-hospital-patients-being-treated-in-corridors-chairs-as-flu-and-covid19-hit">already swamped</a> with patients with influenza and other winter ailments. Winter weather means people tend to gather indoors, in more crowded and poorly ventilated spaces that create ideal conditions for viruses to spread. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1543724644808925184"}"></div></p>
<p>This wave is starting with much busier hospitals than in February, and any additional demand caused by COVID will add more stress to a system already under extreme pressure.</p>
<p>The risk of hospitalisation is around <a href="https://www.health.govt.nz/covid-19-novel-coronavirus/covid-19-data-and-statistics/covid-19-case-demographics">six times higher</a> in people over 70 compared to younger groups. Even if the number of cases in this wave is lower than in the first wave, <a href="https://www.covid19modelling.ac.nz/waning-of-immunity-and-re-infection-with-omicron/">our modelling shows</a> the shift in age distribution means it’s possible the number of hospitalisations will actually be higher. </p>
<h2>What to do</h2>
<p>The vaccine is still our best line of defence against COVID. It provides a high level of protection against getting seriously ill, even if it is less effective at preventing infection with BA.5. </p>
<p>That protection does wane over time, which is why a <a href="https://www.beehive.govt.nz/release/more-free-flu-vaccines-and-second-covid-19-booster-groups-risk-hospitalisation">fourth dose is now available</a> to over 50s. If you or your whānau are eligible for a vaccination, whether it’s the first dose or the fourth, now is a really good time to get it. </p>
<p>Strong uptake of fourth doses in older age groups, as well as third doses among the <a href="https://www.health.govt.nz/covid-19-novel-coronavirus/covid-19-data-and-statistics/covid-19-vaccine-data">one million New Zealanders currently eligible</a>, is the best way we have to mitigate this wave. </p>
<p>The influenza vaccine is also important as it can prevent more people getting sick this winter and ease the burden on the healthcare system. Free flu vaccines are <a href="https://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/influenza/flu-influenza-vaccines/getting-flu-jab">available</a> from GPs and pharmacies for everyone over 65, for Māori and Pacific people over 55, and for children aged between three and 12. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-flu-cases-surge-vaccination-may-offer-some-bonus-protection-from-covid-as-well-183613">As flu cases surge, vaccination may offer some bonus protection from COVID as well</a>
</strong>
</em>
</p>
<hr>
<p>Other easy measures – using high-quality masks indoors, testing and staying home if sick – remain important. Rapid antigen tests (RATs) are an extremely useful tool for managing risk. They are a reliable indicator of whether someone is <a href="https://www.nature.com/articles/s41564-022-01105-z">currently infectious</a>. </p>
<p>Doing a RAT before visiting a vulnerable person or before large gatherings is an excellent way to reduce risk. They are <a href="https://www.health.govt.nz/covid-19-novel-coronavirus/covid-19-health-advice-public/covid-19-testing/rapid-antigen-testing-rat">available for free</a> to anyone with symptoms or whose household members have tested positive. </p>
<figure class="align-center ">
<img alt="A person doing a RAT test" src="https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472899/original/file-20220706-23-4z7zkd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">RATs help reduce the risk of spreading the virus and are free to those eligible.</span>
<span class="attribution"><span class="source">Getty Images</span></span>
</figcaption>
</figure>
<p>Even if you test negative on a RAT but have respiratory symptoms, you could have flu or another virus. Staying home when sick is the best way to protect others and reduce the rates of sickness this winter.</p>
<p>The pandemic is clearly not over yet. The virus will continue to evolve to get around our immunity and this will lead to ongoing waves. But we are not helpless in the face of it. <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/modified-mrna-covid-shots-could-increase-protection-boosters-ema-2022-07-01/">Updated vaccines</a>, better treatments, action to lower transmission through improved ventilation, and the build-up of hybrid immunity will continue to blunt its effects.</p><img src="https://counter.theconversation.com/content/186394/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Plank works for the University of Canterbury and receives funding from the New Zealand Government for mathematical modelling of Covid-19.</span></em></p><p class="fine-print"><em><span>Audrey Lustig is affiliated with Manaaki Whenua Landcare Research and receives funding from the New Zealand Government for mathematical modelling of Covid-19.</span></em></p><p class="fine-print"><em><span>David Welch works for the University of Auckland and has received funding from MBIE, MoH, ESR, and HRC.</span></em></p><p class="fine-print"><em><span>Giorgia Vattiato is affiliated with the University of Auckland and receives funding from the New Zealand Government for mathematical modelling of Covid-19.</span></em></p>The last Omicron wave affected younger people. But the new BA.5 variant is seeing case numbers in older age groups higher than ever before – just as hospitals are under the most pressure.Michael Plank, Professor in Applied Mathematics, University of CanterburyAudrey Lustig, Research scientist, Manaaki Whenua - Landcare ResearchDavid Welch, Senior Lecturer, University of Auckland, Waipapa Taumata RauGiorgia Vattiato, Research fellow, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1859202022-07-05T14:45:41Z2022-07-05T14:45:41ZCOVID vaccines: our current shots could soon be updated to target new variants – an immunology expert explains<figure><img src="https://images.theconversation.com/files/472492/original/file-20220705-26-7sobc3.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6243%2C4364&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/coronavirus-prevention-treatment-concept-senior-female-1897703164">Prostock-studio/Shutterstock</a></span></figcaption></figure><p>More than two years into the pandemic, SARS-CoV-2, the virus that causes COVID-19, continues to challenge us. Its ability to rapidly mutate has seen the evolution of increasingly infectious variants that are getting better at hiding from our immune response.</p>
<p>Vaccines are a huge achievement of modern-day science and have played a crucial role in reducing the very worst impacts of COVID. But are the vaccines we currently have able to deal with the newest COVID variants?</p>
<p>The current COVID vaccines are all based on the genetic building blocks, or the <a href="https://virological.org/t/novel-2019-coronavirus-genome/319">DNA sequence</a>, of the original ancestral strain of SARS-CoV-2. The majority of these vaccines target the spike protein – the part of the virus that attaches to our cells to gain entry. </p>
<p>The vaccines work by enabling our immune cells to mount a targeted response to the spike protein, including generating antibodies known as neutralising antibodies. These stop viruses getting into our cells, and help other immune cells find and destroy any viral intruders.</p>
<p>But SARS-CoV-2 is a slippery customer and has been mutating with notable changes to the <a href="https://github.com/cov-lineages/pango-designation/issues/773">spike protein</a>. That means those vaccine-induced neutralising antibodies are less effective than they once were.</p>
<h2>Is it time for a new generation of COVID vaccines?</h2>
<p>The idea to vaccinate against variants rather than the ancestral strain is gaining traction. This is not a new concept in vaccine development. Our annual flu shots, for example, target circulating variants.</p>
<p>One approach is to create what’s called a “bivalent” vaccine that targets the spike protein from omicron (BA.1) as well as the ancestral strain. Moderna is currently testing this option in combined phase 2 and 3 human trials. Data yet to be peer-reviewed suggests this results in around a <a href="https://www.medrxiv.org/content/10.1101/2022.06.24.22276703v1">two-fold increase</a> in neutralising antibodies against BA.1, compared with the original COVID vaccines.</p>
<p>Other Moderna trials are looking at <a href="https://investors.modernatx.com/news/news-details/2022/Moderna-Announces-Clinical-Update-on-Bivalent-COVID-19-Booster-Platform/default.aspx">different bivalent combinations</a>, including vaccines that target the ancestral and beta strains, which look promising. </p>
<p>Pfizer has also released <a href="https://www.statnews.com/2022/06/25/pfizer-says-its-omicron-containing-boosters-outperform-current-vaccine/">trial data</a> on its booster candidate specifically tailored against BA.1. The company says this reformulation induced an immune response to BA.1 superior to that produced by its original COVID vaccine. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-19-vaccine-boosters-is-a-third-dose-really-needed-164125">COVID-19 vaccine boosters: is a third dose really needed?</a>
</strong>
</em>
</p>
<hr>
<p>So should we be investing in these new vaccine candidates? The <a href="https://www.statnews.com/2022/06/29/fda-dont-rush-to-change-covid-19-vaccine-composition/">US Food and Drug Administration</a> seems to think so, having recently approved the use of these omicron-specific shots later this year.</p>
<p>However, investing in and rolling out new vaccines is not cheap, and there are important questions we need to address. As we know, SARS-CoV-2 is ever mutating and changing. It was less than a year ago that the delta strain dominated around the world, and before that we had alpha and beta. So are omicron variants the right ones to be targeting? Will they still be dominant a year from now? We simply don’t know.</p>
<p>Even with omicron strains there is variation. The BA.1 variant that these new vaccine candidates target has recently been outcompeted by <a href="https://twitter.com/Dr_D_Robertson/status/1542854037606961158">BA.4 and BA.5</a>. The BA.4 and BA.5 variants are even more resistant to neutralising antibodies, typically three- or four-fold, than <a href="https://www.gavi.org/vaccineswork/five-things-weve-learned-about-ba4-and-ba5-omicron-variants">BA.1</a>. So the question is, if omicron pervades, would these omicron BA.1 vaccines work better against BA.4 and BA.5 than the original vaccines? Data still to be peer reviewed suggests the bivalent vaccines may be a little <a href="https://www.medrxiv.org/content/10.1101/2022.06.24.22276703v1">better</a> than the original vaccines. </p>
<p>However, omicron may be a poor vaccine candidate as recent data shows that omicron infection doesn’t produce robust immunity and is characterised by low levels of <a href="https://www.science.org/doi/10.1126/science.abq1841">neutralising antibodies</a>, which need to be higher and more persistent to prevent rapid reinfection. This could go a long way to explaining why so many of us are catching COVID multiple times. If we see the same thing with our vaccine-induced immunity to omicron, omicron-specific vaccines may not be a worthwhile investment.</p>
<figure class="align-center ">
<img alt="An illustration of SARS-CoV-2, the coronavirus that causes COVID-19." src="https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472498/original/file-20220705-26-k7np96.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">COVID vaccines target SARS-CoV-2’s spike protein.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/sarscov2-viruses-binding-ace2-receptors-on-1705841698">Kateryna Kon/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Other strategies</h2>
<p>None of this means we should stop looking for long-term protective vaccines. But perhaps there’s scope to focus on different strategies. Two exciting avenues are emerging. </p>
<p>The first is <a href="https://theconversation.com/covid-why-t-cell-vaccines-could-be-the-key-to-long-term-immunity-174494">vaccines</a> that target other parts of the viral structure that are more stable, or vaccines that target multiple parts of the virus. This might not result in a vaccine that can fully prevent infection, but may be more durable than the current vaccines. </p>
<p>Another avenue involves capitalising on the ability of neutralising antibodies in the nose <a href="https://rupress.org/jem/article/219/7/e20220638/213286/Potent-human-broadly-SARS-CoV-2-neutralizing-IgA">and throat</a> to target SARS-CoV-2 at its point of entry. These antibodies create a barrier that stops the virus getting into the body, so a vaccine that generates neutralising antibodies in the nose and throat could stop the virus in its tracks. Studies trialling <a href="https://www.nature.com/articles/s41577-021-00583-2">nasal vaccines</a> look promising, although these are still at early stages. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-nasal-sprays-could-offer-advantages-over-traditional-vaccines-a-virologist-explains-how-they-work-181371">COVID nasal sprays could offer advantages over traditional vaccines – a virologist explains how they work</a>
</strong>
</em>
</p>
<hr>
<p>Where does this leave us now? An ideal vaccine candidate would elicit long-lived neutralising antibodies and give us life-long immunity. Instead, we’ve learnt that for COVID, our immune system needs boosters to top up those neutralising antibodies and bolster the numbers of memory cells that support immunity.</p>
<p>The last UK-wide booster campaign was in <a href="https://www.gov.uk/government/news/25m-boosters-in-uk-as-public-urged-to-get-boosted-now">December 2021</a>. Studies had shown that COVID vaccination followed by infection lead to <a href="https://www.nature.com/articles/d41586-022-00961-3">months of immunity</a>, but this was before omicron, which we now know doesn’t produce robust <a href="https://www.science.org/doi/10.1126/science.abq1841">immunity</a>. Against omicron, many of us will have minimal neutralising antibodies left.</p>
<p>With the high likelihood of another variant in the <a href="https://www.mrc-bsu.cam.ac.uk/tackling-covid-19/nowcasting-and-forecasting-of-covid-19/">autumn</a>, alongside fears of a <a href="https://www.gov.uk/government/publications/national-flu-immunisation-programme-plan">bad flu season</a>, it would seem prudent to embark on an autumn booster campaign with much wider coverage than the spring campaign. This means not just targeting <a href="https://www.gov.uk/government/news/jcvi-provides-interim-advice-on-an-autumn-covid-19-booster-programme">over 65s and others at higher risk</a> as is currently planned, but extending eligibility to younger age groups. </p>
<p>Crucially we must reach those who are not fully vaccinated, so any campaign should include targeted community education. This should also happen alongside other mitigation strategies like mask-wearing to keep us safe and allow us to live with COVID.</p><img src="https://counter.theconversation.com/content/185920/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sheena Cruickshank does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Is it time for a new generation of COVID vaccines? Here’s where the research is at.Sheena Cruickshank, Professor in Biomedical Sciences, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1839182022-06-02T20:26:38Z2022-06-02T20:26:38ZHerd immunity was sold as the path out of the pandemic. Here’s why we’re not talking about it any more<figure><img src="https://images.theconversation.com/files/465611/original/file-20220527-18-dvoa4u.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1000%2C666&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-plastic-blue-toy-figure-stand-1074052646">Shutterstock</a></span></figcaption></figure><p>Early in the pandemic, the term “herd immunity” hit the headlines, along with a polarised discussion on how to achieve it.</p>
<p>Some groups were attached to the <a href="https://theconversation.com/the-herd-immunity-route-to-fighting-coronavirus-is-unethical-and-potentially-dangerous-133765">now-discredited notion</a> of letting a dangerous virus rip through the population to reach the critical level of population immunity needed to reduce transmission.</p>
<p>But a more serious conversation focussed on the prospect of attaining herd immunity by vaccination. </p>
<p>This is the idea that vaccines – when available and taken up at sufficient levels – could squash virus transmission. This would lead to the possible <a href="https://theconversation.com/eradication-elimination-suppression-lets-understand-what-they-mean-before-debating-australias-course-142495">elimination or eradication</a> of SARS-CoV-2, the virus that causes COVID. </p>
<p>The <a href="https://news.harvard.edu/gazette/story/2021/02/vaccines-should-end-the-pandemic-despite-the-variants-say-experts/">promise</a> was this would herald the return of life back to normal.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1368380912644292612"}"></div></p>
<p>It’s understandable why this notion gained so much attention, as it promised a complete return to a world without COVID. But in reality it was probably always a pipe dream.</p>
<p>As time wore on, herd immunity became even less reachable.</p>
<p>Here’s why we’re not talking about it any more, even with the high vaccination rates we see today.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/80-vaccination-wont-get-us-herd-immunity-but-it-could-mean-safely-opening-international-borders-162863">80% vaccination won't get us herd immunity, but it could mean safely opening international borders</a>
</strong>
</em>
</p>
<hr>
<h2>What is herd immunity?</h2>
<p>If enough people in the community develop immunity to an infectious agent such as a virus, an epidemic is unable to grow.</p>
<p>In fact, much like a bushfire goes out when it runs out of fuel to burn, an epidemic <a href="https://theconversation.com/what-is-herd-immunity-and-how-many-people-need-to-be-vaccinated-to-protect-a-community-116355">begins to decline</a> when the virus runs out of susceptible people to infect.</p>
<p>The level of vaccine coverage needed in a population to get you over the line to achieve herd immunity is the “herd immunity threshold”.</p>
<p>This depends on two main parameters – the infectiousness of the virus and the effectiveness of the vaccine. </p>
<p><a href="https://theconversation.com/what-is-herd-immunity-and-how-many-people-need-to-be-vaccinated-to-protect-a-community-116355">In short</a>, the more infectious the virus and the less effective the vaccine, the more people you need to vaccinate to achieve herd immunity.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-herd-immunity-and-how-many-people-need-to-be-vaccinated-to-protect-a-community-116355">What is herd immunity and how many people need to be vaccinated to protect a community?</a>
</strong>
</em>
</p>
<hr>
<h2>Further and further out of reach</h2>
<p>As the pandemic progressed, herd immunity via vaccination moved further and further out of reach. In fact, based on what we know about currently circulating viral variants, today, herd immunity via vaccination is mathematically impossible.</p>
<p>Back at the beginning of 2020, we were grappling with the original strain of SARS-CoV-2, which was much less infectious than current circulating variants. </p>
<p>The original strain had an estimated R0 (basic reproduction number) of <a href="https://www.bmj.com/content/369/bmj.m1891">two to three</a>. That is, someone infected with the virus would spread it to, on average, two to three others.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Pins on a board, connected with string" src="https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466508/original/file-20220601-49630-dv2meh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Each person with the ancestral strain of the virus infected two to three others. But later variants infected many more.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/linking-entities-networking-social-media-sns-1044017923">Shutterstock</a></span>
</figcaption>
</figure>
<p>If we assume we were working with a vaccine with an effectiveness of 80%, this yields a herd immunity threshold estimate of 60-80%. That is, when the original strain of the virus was circulating we would have needed to vaccinate 60-80% of the whole population to see the epidemic decline. Mathematically at least, this was not out of reach.</p>
<p>However, as we know, circumstances have changed dramatically over the course of the pandemic, with the original SARS-CoV-2 virus superseded by far more infectious variants.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-is-a-covid-mutation-a-new-variant-and-when-is-it-a-subvariant-and-whats-a-recombinant-182333">When is a COVID mutation a new variant, and when is it a subvariant? And what’s a recombinant?</a>
</strong>
</em>
</p>
<hr>
<p>Although estimates of the infectiousness for the variants are subject to some uncertainty, it is reasonable to assume Delta has a reproduction number of about five and Omicron may be double this, somewhere <a href="https://theconversation.com/new-covid-variants-may-be-more-transmissible-but-that-doesnt-mean-the-r0-or-basic-reproduction-number-has-increased-186826">around 10</a>.</p>
<p>Based on these numbers for Delta and Omicron, the herd immunity threshold estimates go to over 100%. </p>
<p>As you cannot vaccinate more than 100% of the population, you can see how relying on vaccination to achieve herd immunity has become progressively more mathematically impossible as the pandemic progressed.</p>
<h2>That’s not all</h2>
<p>Over the course of the pandemic we have learnt more about how the vaccines have performed in the real world and the nature of our immune response.</p>
<p><strong>Vaccines don’t block all transmission</strong></p>
<p>Herd immunity via vaccination, and the calculations above, assume vaccines stop transmission 100% of the time.</p>
<p>Although vaccines reduce transmission to a <a href="https://theconversation.com/mounting-evidence-suggests-covid-vaccines-do-reduce-transmission-how-does-this-work-160437">significant degree</a>, they do not prevent it completely. If we factor this into our calculations, the challenge to achieve herd immunity becomes harder again.</p>
<p><strong>Immunity wanes over time</strong></p>
<p>Attaining herd immunity also assumes immunity against COVID is maintained long term. But we now know immunity <a href="https://theconversation.com/immunity-to-covid-19-may-not-last-this-threatens-a-vaccine-and-herd-immunity-142556">wanes</a> after vaccination and after natural infection.</p>
<p>So if immunity is not sustained, even if herd immunity were theoretically possible, it would only be transient. Preserving it would only come with significant effort, requiring regular delivery of boosters for the whole population.</p>
<p><strong>New viral variants</strong></p>
<p>Then we’ve seen new <a href="https://theconversation.com/why-are-there-so-many-new-omicron-sub-variants-like-ba-4-and-ba-5-will-i-be-reinfected-is-the-virus-mutating-faster-182274">variants</a> emerge with an ability to evade the immune response. Any change in the immunogenicity of new variants moves the goal posts further away, compromising our ability to achieve herd immunity to an even greater extent.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1374575449918083073"}"></div></p>
<h2>So why are we bothering to vaccinate?</h2>
<p>While attaining herd immunity via vaccination is no longer a realistic proposition, this needs to be put into perspective.</p>
<p><strong>Vaccines go hand-in-hand with other measures</strong></p>
<p>It’s better to consider herd immunity as a gradient rather than a binary concept. That is, even if we don’t reach the herd immunity threshold, the greater the proportion of the population vaccinated, the more difficult it becomes for the virus to spread.</p>
<p>Therefore, vaccination can combine with other behavioural and environmental measures (such as physical distancing, wearing masks and improving ventilation), to substantially impact the ability of the virus to move through the population.</p>
<p><strong>Vaccines protect individuals</strong></p>
<p>Despite the allure of herd immunity, the primary purpose of COVID vaccination has always been to protect individuals from severe illness and death, and thus the impact of disease on the population. </p>
<p>In this regard, despite the waning protection against infection, vaccines appear to afford more <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2115481">sustained protection</a> against severe disease.</p>
<p>So being vaccinated remains as important now as it has always been. Right now, at the start of winter and with few COVID restrictions, it has never been more important to ensure you are fully vaccinated.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-well-do-covid-vaccines-work-in-the-real-world-162926">How well do COVID vaccines work in the real world?</a>
</strong>
</em>
</p>
<hr>
<p><em>Correction: this article originally estimated Omicron had an R0 of around 20, making it among the most infectious diseases known. This has been replaced with the estimate of around 10. The herd immunity threshold has also been updated from up to 100-118% to over 100%.</em></p><img src="https://counter.theconversation.com/content/183918/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hassan Vally does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Achieving herd immunity via vaccination was always going to be a hard ask. Now it’s mathematically impossible.Hassan Vally, Associate Professor, Epidemiology, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.