tag:theconversation.com,2011:/us/topics/rapid-tests-85640/articlesRapid tests – The Conversation2024-03-01T13:33:07Ztag:theconversation.com,2011:article/2216032024-03-01T13:33:07Z2024-03-01T13:33:07ZCOVID-19 rapid tests still work against new variants – researchers keep ‘testing the tests,’ and they pass<figure><img src="https://images.theconversation.com/files/575188/original/file-20240213-26-dfzfvf.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4707%2C2718&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rapid tests are inexpensive, easy to use and give fast results, usually within 10 to 15 minutes.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/negative-test-result-by-using-rapid-test-device-for-royalty-free-image/1322901789?phrase=rapid+home+testing+covid&adppopup=true">Violeta Stoimenova/E+ via Getty Images</a></span></figcaption></figure><p>By September 2020, just six months after COVID-19 triggered shutdowns across the U.S., it was clear that <a href="https://doi.org/10.1140/epjp/s13360-023-03719-6">SARS-CoV-2, the virus that causes COVID-19, had mutated</a> from its original form. </p>
<p>The question quickly arose whether <a href="https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/understanding-home-otc-covid-19-antigen-diagnostic-test-results">existing rapid antigen tests</a> could detect newly emerging variants.</p>
<p>Using clinical samples obtained from diagnostic labs throughout the U.S. from 2020 to 2023, the National Institutes of Health, through its <a href="https://doi.org/10.1109/OJEMB.2021.3116490">Variant Task Force</a>, analyzed the effectiveness of more than 100 rapid antigen test kits on over 300 variants. The vast majority of the kits were able to detect new as well as prior previously known variants.</p>
<p>We are a team of researchers who have spent the past few years <a href="https://www.nibib.nih.gov/covid-19/radx-tech-program">researching COVID-19 tests</a> for their accuracy and performance. We understand why the public may still have questions about whether these tests are reliable, particularly as new variants continue to appear. </p>
<p>Here are answers to some of those questions:</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/nwAfKVBStj8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">As of early March 2024, the JN.1 variant is responsible for nearly all COVID-19 cases nationwide.</span></figcaption>
</figure>
<h2>Do these tests work?</h2>
<p>There are <a href="https://theconversation.com/whats-the-difference-between-a-pcr-and-antigen-covid-19-test-a-molecular-biologist-explains-170917">two major types of tests</a> for the detection of SARS-CoV-2. </p>
<p>The first, called a <a href="https://www.mayoclinic.org/tests-procedures/covid-19-diagnostic-test/about/pac-20488900">RT-PCR test</a>, is more than 95% accurate for detecting the virus. These were the tests that most Americans were given at drive-through and walk-in testing sites early in the pandemic. The vast majority are now done at a doctor’s office or clinic, though there are <a href="https://cuehealth.com/">some home PCR tests</a>, which typically cost five to 10 times more than rapid antigen tests.</p>
<p>The other type is <a href="https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/understanding-home-otc-covid-19-antigen-diagnostic-test-results">an antigen test</a>, commonly known as a rapid test, with an accuracy rate of more than 80%. Most of these tests are sold over the counter at supermarkets and pharmacies. </p>
<p>Rapid antigen tests are relatively inexpensive, can be used without prior training and give quick results, typically within 10 or 15 minutes. One drawback is that they are less accurate than PCR tests, especially early in an infection when there is less virus present in the body.</p>
<p>Despite these inherent limitations, our team has demonstrated that these tests <a href="https://doi.org/10.7326/M22-0760">perform as well in 2024</a> as they did earlier in the pandemic, when different variants were circulating – even though our initial study was completed in January 2022. That’s because the virus protein detected by antigen tests has not changed much over the last two years, unlike other parts of the virus that have undergone many mutations. Another study, which tested the accuracy of rapid antigen tests from 2020 to 2022, <a href="https://doi.org/10.1016/j.isci.2022.103968">found similar results</a>. </p>
<p>That said, researchers like us continue to “test the tests,” both in computer simulations and in the lab, to detect new SARS-CoV-2 variants. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Researchers wearing masks and other protective gear sit under tents collecting samples during a COVID-19 testing study." src="https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578991/original/file-20240229-16-t016d9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">UMass Chan Medical School research staff members enroll participants in a COVID-19 testing study in Worcester, Mass., in the fall of 2020.</span>
<span class="attribution"><span class="source">Nathaniel Hafer</span></span>
</figcaption>
</figure>
<h2>I have symptoms. When should I take a test?</h2>
<p>If you have symptoms, take a rapid test <a href="https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html">as soon as possible</a>. If you test positive, you can be reasonably certain that you’re infected. If you’re negative, wait two days and test again. </p>
<p>This waiting period is important because it takes a few days <a href="https://doi.org/10.1093/infdis/jiab337">for the virus to build up</a> to <a href="https://doi.org/10.1371/journal.pbio.3001216">levels that are detectable by the rapid test</a>. Recent research has shown that the time it takes for this to happen is <a href="https://doi.org/10.1093/cid/ciad582">slightly longer with the omicron family of variants</a> compared to variants from a few years ago.</p>
<h2>I was exposed, but have no symptoms. When do I test?</h2>
<p>If you’ve been exposed to somebody but don’t have symptoms, the current recommendation is to wait <a href="https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html#:%7E">four to five days before taking a rapid test</a>. If you’re negative, wait two days and then test again. </p>
<p>If you’re still negative, take a third test two more days later. This is the best way to <a href="https://doi.org/10.7326/M23-0385">detect COVID-19 infection without symptoms</a>.</p>
<p>It’s also recommended that you take a rapid test as close as possible to the time you’re visiting someone who is at risk for getting sick, especially if you think you may have been exposed.</p>
<h2>When am I contagious?</h2>
<p>Most people who have symptoms and test positive are contagious. If you no longer have symptoms and are no longer testing positive, it’s <a href="https://doi.org/10.1001/jamanetworkopen.2022.25331">likely that you’re not contagious</a>. </p>
<p>But there are some exceptions to this general rule. It’s possible to be infected, have no symptoms and be contagious. This is especially true early on in a person’s infection. </p>
<h2>Should I swab my nose or throat?</h2>
<p>The best advice is to follow the instructions that come with your test. For antigen tests in the U.S., this means taking a swab of your nose. </p>
<p>Although one study from Denmark reported that <a href="https://doi.org/10.1001/jamanetworkopen.2023.44295">antigen tests were more sensitive</a> when a health care provider swabbed the throat, the same study said that when a person swabbed themselves, nose samples were more accurate than throat samples. Other studies have shown <a href="https://doi.org/10.7326/M22-0202">that swabbing the throat</a> <a href="https://doi.org/10.1101/2022.02.08.22270685">was no better than swabbing the nose</a>. </p>
<p>A new program <a href="https://www.nih.gov/news-events/news-releases/home-test-treat-program-extends-nationwide">funded by the National Institutes of Health</a> and rolled out in late 2023 – the <a href="https://www.test2treat.org/">Home Test to Treat study</a> – offers free testing, telehealth and treatment for COVID-19 and the flu <a href="https://www.umassmed.edu/news/news-archives/2023/12/umass-chan-partners-with-expanded-federal-home-test-to-treat-program-for-covid-19-flu/">without leaving home</a>. To date, more than 60,000 people have enrolled. The study uses commercially available rapid tests and typically arrive a few days after they’re requested.</p>
<p>For those millions of Americans who are unable to travel, are without insurance, <a href="https://doi.org/10.1001/jamanetworkopen.2022.41144">don’t live near a clinic</a> or simply don’t want to expose others to their symptoms, this new program could help save lives.</p><img src="https://counter.theconversation.com/content/221603/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathaniel Hafer receives funding from the National Institutes of Health and the National Science Foundation. </span></em></p><p class="fine-print"><em><span>Anuradha Rao receives funding from the National Institute of Biomedical Imaging and Bioengineering and the National Center for Advancing Translational Sciences. </span></em></p><p class="fine-print"><em><span>Apurv Soni receives funding from the National Institutes of Health.</span></em></p>Research shows that rapid antigen tests are performing as well at detecting the most recent dominant variants as they did with the earliest strains in the COVID-19 pandemic.Nathaniel Hafer, Associate Professor of Molecular Medicine, UMass Chan Medical SchoolAnuradha Rao, Assistant Professor of Pediatrics, Emory UniversityApurv Soni, Assistant Professor of Medicine, UMass Chan Medical SchoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1883922022-08-15T16:08:23Z2022-08-15T16:08:23ZCOVID: masks and free tests may not curb omicron spread – here’s what we should focus on instead<figure><img src="https://images.theconversation.com/files/478337/original/file-20220809-19-j6dhed.jpg?ixlib=rb-1.1.0&rect=27%2C0%2C3029%2C2018&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/man-wearing-disposable-medical-mask-shopping-1666720927">Maria Sbytova/Shutterstock</a></span></figcaption></figure><p>As we face continued waves of COVID-19, there have been various calls for the reintroduction of measures like mask mandates and <a href="https://www.bmj.com/content/378/bmj.o1793">free tests</a> in the UK. But how much of a difference would these sorts of interventions actually make on COVID spread in the omicron era?</p>
<p>Let’s take a look at UK and global data to get an idea. It’s important to focus on 2022, as this data captures the period during which the rapidly spreading omicron variants have been circulating. </p>
<p>Data from the UK’s <a href="https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/5august2022">Office for National Statistics</a> (ONS) shows how common COVID has been over time. These are nationally representative estimates from a large survey, and don’t depend on the availability of tests.</p>
<figure class="align-right ">
<img alt="Four graphs showing the prevalence of COVID across the UK in 2021–2022, explained in following paragraph." src="https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1517&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1517&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1517&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1907&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1907&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478521/original/file-20220810-9577-oao8ef.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1907&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/5august2022">Office for National Statistics (ONS), UK</a></span>
</figcaption>
</figure>
<p>As you can see in the graph to the right, which charts COVID cases across the UK from not long after last July’s “freedom day”, infections have risen much higher in the omicron era compared with 2021. Omicron spreads so rapidly because it is both highly infectious and able to <a href="https://www.nature.com/articles/s41392-022-01105-9">evade immunity</a> from our current vaccines and prior infections. </p>
<p>Two years into the pandemic, we may also be past the peak of how well mask mandates and testing policies would be adhered to, should they be put in place. We know, for example, that people tended not to follow the rules as closely <a href="https://theconversation.com/lockdown-mobile-data-suggests-europeans-may-not-have-followed-rules-as-strictly-in-the-second-wave-154815">during the second wave</a> of the pandemic as they did during the first.</p>
<p>Together these things mean we might expect COVID to now be very difficult to control.</p>
<h2>Prevalence and policies</h2>
<p>We can see the January, April and July peaks where roughly 7%, 8% and 6% of people in England were infected respectively.</p>
<p>During the January wave the UK offered free tests. These <a href="https://www.nhs.uk/conditions/coronavirus-covid-19/testing/get-tested-for-coronavirus/">ended</a> on April 1, around the time the second wave peaked, so were available while that wave grew, but not for the July wave. </p>
<p>During the first wave the UK also had mask mandates covering public transport (for example, the Transport for London mandate ended <a href="https://tfl.gov.uk/info-for/media/press-releases/2022/february/tfl-to-no-longer-require-face-coverings-to-be-worn-on-its-services-from-24-february-but-will-strongly-recommend-them#:%7E:text=Transport%20for%20London%20(TfL)%20has,and%20decreasing%20infection%20rates%20in">on February 24</a>), schools (<a href="https://educationhub.blog.gov.uk/2022/01/19/face-masks-in-classrooms-will-no-longer-be-required-from-20-january-and-in-communal-areas-from-27-january-what-you-need-to-know/">until January 27</a>), and universities (for example, <a href="https://www.ucl.ac.uk/human-resources/face-covering-guidance">UCL’s lasted until May</a>, also covering the April wave).</p>
<p>Notably, the proportion of people voluntarily taking preventative measures has also declined. For example, the ONS reports that <a href="https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/articles/coronaviruscovid19latestinsights/lifestyle">only 34% of people</a> wore masks in the week to July 31, down from 65% in the spring.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-tide-of-the-covid-pandemic-is-going-out-but-that-doesnt-mean-big-waves-still-cant-catch-us-185923">The tide of the COVID pandemic is going out – but that doesn't mean big waves still can't catch us</a>
</strong>
</em>
</p>
<hr>
<p>Below is <a href="https://www.ons.gov.uk/economy/economicoutputandproductivity/output/datasets/visitstolocationtypesusinggooglemobility">Google mobility data</a> (movement data gathered from Google devices) for the UK in 2022.</p>
<p><strong>Mobility in the UK</strong></p>
<figure class="align-center ">
<img alt="A graph depicting Google mobility data for the UK during 2022." src="https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=291&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=291&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=291&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=366&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=366&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478082/original/file-20220808-1331-vi7c4u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=366&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">ONS and Google</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We can see that mobility, a proxy for social mixing (and therefore COVID exposures) increases and is generally highest for the July wave. If masks or free tests were working to suppress COVID, we might expect the July wave to be significantly larger in their absence, particularly given the increase in social mixing. But it’s actually smaller than the previous two waves.</p>
<p>While many respiratory diseases peak in winter, the evidence isn’t conclusive on whether or to what degree COVID is <a href="https://www.theguardian.com/world/2022/jul/17/unexpected-changing-waves-covid-seasonal">affected by the seasons</a>. So the slightly lower peak of the July wave can’t necessarily be explained by the summer weather.</p>
<p>The seemingly minimal impact of these measures makes sense if we consider that masks don’t protect us when we’re eating or drinking with others, and that they’re not usually worn <a href="https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2777973?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=033121">among friends and family</a> or in our homes. Further, there may simply be too many COVID exposures when cases are high and people are socialising at pre-pandemic levels, even for good masks to make a significant difference.</p>
<p>The situation is similar when we consider testing. Many people may have already transmitted omicron to others by the time they test, while other people may be disinclined to test in the first instance. This may especially apply to children and others who dislike testing, or see no end to the pandemic in sight. </p>
<p>Many people may also count the days after a positive test to leave isolation (as per <a href="https://www.gov.uk/guidance/people-with-symptoms-of-a-respiratory-infection-including-covid-19">public health guidance</a>), rather than waiting potentially much longer for a negative test to confirm they’re <a href="https://www.thelancet.com/article/S0140-6736%2821%2902346-1/fulltext">unlikely to be infectious</a> anymore.</p>
<h2>So what’s driving the rise and fall of successive waves?</h2>
<p>It seems likely that <a href="https://twitter.com/adamjkucharski/status/1536613175247917058?s=20&t=GxYeqT_SgI48wt46Ycqj5A">COVID waves</a> are now being driven almost entirely by waning hybrid immunity. This is immunity from vaccines and prior infections, which falls over time, precipitating the next wave. In this context masks, free tests, and other non-restrictive interventions that don’t confer immunity will probably <a href="https://www.stuff.co.nz/national/explained/129404942/covid-nz-why-longterm-covid-restrictions-are-less-effective-than-advertised">have a limited effect</a>.</p>
<p>Could the UK’s July wave have been smaller if free tests or mask mandates were in place? Possibly, but given cases are declining now despite high mixing largely without masks or tests, it might instead have been a bit flatter and longer with a similar total number of people infected until the same level of immunity was reached.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/coronaviruses-a-brief-history-135506">Coronaviruses – a brief history</a>
</strong>
</em>
</p>
<hr>
<p>Looking at other countries it’s apparent that very few are successfully controlling omicron. For example, the once-envied low COVID countries like Japan, Taiwan, Singapore and New Zealand are all seeing significant numbers of cases despite stricter COVID control policies than the UK.</p>
<p><strong>COVID around the world</strong></p>
<figure class="align-center ">
<img alt="Chart showing UK cases much lower than other countries." src="https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478095/original/file-20220808-6012-ysycaa.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Confirmed COVID cases per million people in Japan, Taiwan, Singapore, New Zealand and the UK.</span>
<span class="attribution"><a class="source" href="https://ourworldindata.org/">Our World in Data</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Only China appears to be controlling omicron’s spread, but in an <a href="https://www.bbc.co.uk/news/world-asia-china-62322484">unsustainable way</a> with lockdowns, compulsory mass testing, and other restrictive interventions.</p>
<h2>What next?</h2>
<p>We are past the emergency phase of the pandemic and COVID is now far from <a href="https://twitter.com/timcolbourn/status/1541385588959576064?s=20&t=GxYeqT_SgI48wt46Ycqj5A">our top health problem</a>.</p>
<p>Given free tests especially are <a href="https://twitter.com/EdConwaySky/status/1536282103997931521?s=20&t=-gyCDvMBeHXmnI5HtnOvJA">expensive</a> and likely to have minimal benefit at the population level, I would argue that the resources that would be required to provide them should be spent on other areas of health.</p>
<p>Focus on NHS <a href="https://www.bbc.co.uk/news/health-62267282">staffing</a>, <a href="https://www.independent.co.uk/news/health/ambulance-delay-uk-nhs-backlog-b2122946.html">ambulance</a> and <a href="https://www.bmj.com/content/377/bmj.o1485/rr-1">primary care</a> crises is urgently needed in the UK. Much more could be done for leading causes of death such as heart disease and dementia, as well as mental health and poor quality of life, not least considering the <a href="https://www.bbc.co.uk/news/business-62475171">looming winter economic crisis</a>. </p>
<p>Globally, child health would benefit from increased investment. As an example, <a href="https://www.who.int/news-room/fact-sheets/detail/pneumonia">childhood pneumonia</a> kills <a href="https://data.unicef.org/resources/covid-19-confirmed-cases-and-deaths-dashboard/">more than 300 times</a> as many children under five as COVID in a year, many for want of simple antibiotics or oxygen. </p>
<p>We may need to accept that there are limits on what we can do <a href="https://twitter.com/timcolbourn/status/1473425295319384064?s=20&t=GxYeqT_SgI48wt46Ycqj5A">to control COVID moving forward</a>. We can take comfort in the fact that fewer people are getting very sick and dying from COVID thanks to vaccines, and by focusing our attention on addressing bigger unsung health problems, at home and abroad.</p><img src="https://counter.theconversation.com/content/188392/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Colbourn 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 to accept the limits to COVID control and invest elsewhere in the health system?Tim Colbourn, Professor of Global Health Systems, Epidemiology and Evaluation, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1863682022-07-13T17:05:48Z2022-07-13T17:05:48ZI have COVID symptoms. Should I do a test?<figure><img src="https://images.theconversation.com/files/473841/original/file-20220713-16-ikbxhp.jpg?ixlib=rb-1.1.0&rect=44%2C0%2C4965%2C3285&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rapid tests are no longer free in the UK for most people.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-using-cotton-swab-while-doing-1997261021">Photoroyalty/Shutterstock</a></span></figcaption></figure><p>You’ve got a sore throat and feel like you might be coming down with something. A year ago, you would likely have taken a rapid test from your stash, and tested for COVID. But what about now? In many countries you are no longer legally required to self-isolate if you test positive. In the UK and other places, tests are no longer free and many governments have adopted a policy of “<a href="https://www.gov.uk/government/publications/covid-19-response-living-with-covid-19">living with COVID</a>”.</p>
<p>Add to that, you’ve got a jam-packed weekend of summer social engagements you don’t want to miss. While self-isolation is not mandatory, you wouldn’t go out and about if you knew you had COVID. You might think it’s better not to know. </p>
<p>If you’re unsure what to do, you’re not alone. Our <a href="https://psyarxiv.com/d6jcv">ongoing research</a> as part of the <a href="https://www.swansea.ac.uk/research/research-highlights/health-innovation/public-during-pandemic/">Public Views During the Coronavirus Pandemic</a> study, shows that many people are not sure what they should be doing if they feel unwell. This includes how to recognise COVID symptoms, whether they should take a test and whether they should self-isolate. </p>
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<img alt="Quarter life, a series by The Conversation" src="https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><strong><a href="https://theconversation.com/uk/topics/quarter-life-117947?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">This article is part of Quarter Life</a></strong>, a series about issues affecting those of us in our twenties and thirties. From the challenges of beginning a career and taking care of our mental health, to the excitement of starting a family, adopting a pet or just making friends as an adult. The articles in this series explore the questions and bring answers as we navigate this turbulent period of life.</em></p>
<p><em>You may be interested in:</em></p>
<p><em><a href="https://theconversation.com/should-i-still-go-on-holiday-if-i-have-covid-186185?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">Should I still go on holiday if I have COVID?</a></em></p>
<p><em><a href="https://theconversation.com/hybrid-working-post-covid-how-young-professionals-can-optimise-their-time-in-the-office-and-why-they-should-184025?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">Hybrid working post-COVID: how young professionals can optimise their time in the office (and why they should)</a></em></p>
<p><em><a href="https://theconversation.com/long-social-distancing-how-young-adults-habits-have-changed-since-covid-183837?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">Long social distancing: how young adults’ habits have changed since COVID</a></em></p>
<hr>
<p>In a <a href="https://www.ons.gov.uk/peoplepopulationandcommunity/wellbeing/datasets/publicopinionsandsocialtrendsgreatbritaincoronaviruscovid19andotherillnesses">recent survey</a>, two-thirds of UK adults said they would be very likely to get tested if they had COVID symptoms. But during the current wave, compared with the last wave in March, government data shows the number of people taking tests has been <a href="https://coronavirus.data.gov.uk/details/testing?areaType=nation&areaName=England">much lower</a>. This isn’t particularly surprising, given that tests are no longer free (except lateral flow tests in Wales until the <a href="https://gov.wales/wales-extends-covid-19-testing-throughout-july">end of July</a>.</p>
<p>However, in my view, it’s clear the best thing to do if you think you might have COVID symptoms is to take a rapid test. If you don’t have access to one – or even if you do, and it comes back negative – while you’re feeling unwell, it’s sensible to stay away from others if you can. Here’s why this is still really important.</p>
<h2>Sorting out the symptoms</h2>
<p>Official <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1073762/Living_with_COVID_Easy_Read_Web_Accessible.pdf">government guidance</a> still suggests that you should take a test if you think you might have COVID. And people are <a href="https://www.gov.uk/guidance/people-with-symptoms-of-a-respiratory-infection-including-covid-19">advised</a> to try to stay home and avoid contact with others if experiencing symptoms of a respiratory infection, such as COVID or the flu.</p>
<p>Most people know that the <a href="https://www.nhs.uk/conditions/coronavirus-covid-19/symptoms/main-symptoms/">main official COVID symptoms</a> include a new, continuous cough, a loss of taste or smell, and a fever. A recent <a href="https://yougov.co.uk/topics/health/articles-reports/2022/05/05/how-many-britons-recognise-new-covid-19-symptoms">survey</a> found that roughly nine in ten Britons correctly identified these. </p>
<p>If you have any of these symptoms, you should test if you can. Given the <a href="https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/8july2022">high number of cases</a> in the UK at the moment, the likelihood of having COVID is currently relatively high.</p>
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<strong>
Read more:
<a href="https://theconversation.com/what-are-the-symptoms-of-omicron-174476">What are the symptoms of omicron?</a>
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</em>
</p>
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<p>But as the virus has evolved through the pandemic, more symptoms have been added to the <a href="https://www.gov.uk/guidance/people-with-symptoms-of-a-respiratory-infection-including-covid-19">official list</a>. These include shortness of breath, fatigue, muscle aches or pains, lack of appetite, headache, sore throat, stuffy or runny nose, diarrhoea and nausea. </p>
<p>In fact, recent data from the UK’s <a href="https://health-study.joinzoe.com/post/new-top-5-covid-symptoms">ZOE app</a> (which continues to track people’s self-reported COVID symptoms and test results) suggests that, for people who have been vaccinated, the top five most common symptoms are now a runny nose, headache, sneezing, sore throat and persistent cough. So it seems two of the three symptoms we tend to immediately associate with COVID are not actually among the most common symptoms currently.</p>
<p>People are less likely to be able to identify some of these other symptoms as possible COVID symptoms. For example, in the same survey I mentioned above, <a href="https://yougov.co.uk/topics/health/articles-reports/2022/05/05/how-many-britons-recognise-new-covid-19-symptoms">less than half</a> of people correctly identified feeling nauseated or a loss of appetite as possible COVID symptoms, and only two-thirds identified a blocked or runny nose.</p>
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<img alt="A woman and a man sit on a couch under a blanket. The woman is sneezing." src="https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/473866/original/file-20220713-9312-u56z33.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">COVID symptoms have evolved over time.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/flu-season-has-arrived-shot-young-2129744342">PeopleImages.com - Yuri A/Shutterstock</a></span>
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<p>The evolving symptom profile, along with the fact many COVID symptoms are a lot like cold and flu symptoms, makes figuring out whether or not you might have COVID very difficult.</p>
<p>So again, the best advice is, if in doubt, test. Of course, this is easier said than done without access to free test kits. If you have a limited supply, it’s particularly useful to test when visiting relatives who are <a href="https://www.gov.uk/government/publications/covid-19-guidance-for-people-whose-immune-system-means-they-are-at-higher-risk/covid-19-guidance-for-people-whose-immune-system-means-they-are-at-higher-risk#keeping-yourself-safe">clinically vulnerable</a>, especially if you have any of the symptoms listed above, however mild.</p>
<h2>Living with COVID</h2>
<p>To my mind, “living with COVID” doesn’t mean we can’t get back out there and have fun. It just means that in doing so, we should remember some of the basics of what the pandemic has taught us. Keep up with our vaccinations, and when we feel unwell, get a test if possible. That said, regardless of whether it’s COVID or something else like the flu, consider keeping away from others and wearing a mask. </p>
<p>The rest of the responsibility lies with governments and organisations. My hope is that the government starts providing free tests again soon. If we want to avoid a major wave in autumn or winter this year, then the first step is catching it early and taking action.</p>
<p>Other important measures include ensuring adequate ventilation in buildings, and supporting more flexible work. A culture of <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-019-7138-x">presenteeism</a> – going to work when sick – pervaded before COVID. In the pandemic era and beyond, people need to be supported to work from home if possible, and receive adequate sick pay to discourage them from coming into work when they really are unwell.</p><img src="https://counter.theconversation.com/content/186368/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Nicholas Williams has received funding from Swansea University, the University of Manchester, Senedd Cymru and Public Health Wales for research on COVID-19. However, this article reflects the views of the author only and no funding bodies were involved in the writing or content of this article.</span></em></p>Official guidance still suggests you should take a test if you think you might have COVID – and this is a sensible thing to do.Simon Nicholas Williams, Lecturer in Psychology, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1741482021-12-22T13:13:16Z2021-12-22T13:13:16ZBiden to expand access to at-home COVID kits: 4 essential reads on the critical role of rapid tests<figure><img src="https://images.theconversation.com/files/438738/original/file-20211221-19-pe5c55.jpg?ixlib=rb-1.1.0&rect=10%2C120%2C6699%2C4345&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reflecting on the growing demand for at-home rapid COVID-19 tests.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-performing-a-covid-19-antigen-self-test-at-royalty-free-image/1338929267?adppopup=true">Corinna Kern/Getty Images</a></span></figcaption></figure><p>President Joe Biden has <a href="https://www.nytimes.com/live/2021/12/21/world/omicron-covid-vaccine-tests">outlined plans</a> to massively ramp up COVID-19 testing in an effort to curb – or at least slow – the spread of the highly infectious omicron variant across the U.S.</p>
<p>In a <a href="https://www.cbsnews.com/news/biden-omicron-variant-speech-covid-19-watch-live-today-2021-12-21/">speech on Dec. 21, 2021</a>, Biden said he aimed to get out “as many tests, as quickly as possible” and said free at-home kits would be sent out to Americans beginning in January.</p>
<p>At the forefront of the push against the omicron variant will be new federal testing sites and the distribution of <a href="https://apnews.com/article/coronavirus-pandemic-joe-biden-health-jen-psaki-08ee41d8e7c0af1ad8b4dfb7b434ea61">500 million rapid tests</a>, free of charge, to the public. To enable the speedy rollout of tests, the White House committed to using the <a href="https://www.militarytimes.com/news/your-military/2020/03/19/what-exactly-is-the-defense-production-act/">Defense Production Act</a>, which allows the federal government to “allocate materials, services and facilities” from the private sector to meet the demands of the nation.</p>
<p>The focus on testing comes at a time of <a href="https://www.nbcnews.com/news/us-news/covid-testing-demand-spikes-ahead-christmas-lines-sites-rcna9140">high demand for kits</a> that diagnose infection. The arrival of the omicron variant has coincided with a desire by many to get tested before meeting up with loved ones over the holiday period, resulting in <a href="https://www.cnn.com/2021/12/19/health/covid-omicron-testing/index.html">long lines outside test sites</a> and a <a href="https://www.axios.com/coronavirus-testing-biden-omicron-christmas-8f8270d8-e192-40fd-ad40-b6391869f577.html">run on home kits</a> being sold at pharmacies.</p>
<p>Throughout the coronavirus pandemic, The Conversations’s team of health experts has been on hand to explain why testing is such a crucial part of the response. </p>
<h2>1) What exactly is a rapid COVID-19 test?</h2>
<p>The type of test that Biden is hoping to get into the hands of Americans is a <a href="https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.html">rapid antigen test</a>. </p>
<p>Rapid antigen tests look for proteins from the virus that may be present in samples collected via saliva or a swab up the nostrils.</p>
<p>The tests are relatively cheap and quick, with results known in around 15 minutes. They are, however, not 100% reliable and can miss the early stages of COVID-19 infection. </p>
<p><a href="https://www.fda.gov/consumers/consumer-updates/coronavirus-disease-2019-testing-basics">PCR tests</a>, which are better at detecting low levels of the virus, are usually performed by a doctor or health practitioner – although some are available for home use – after which the samples are sent to a lab.</p>
<p>Like the rapid test, the first step in a PCR test is the collection of genetic material – again, saliva or nostril swab.</p>
<p>After that initial procedure, the sample is amplified through a sophisticated process that causes the test DNA to replicate until there are a billion copies of the original piece.</p>
<p>This allows for a very high level of accuracy, with the test being able to detect the tiniest presence of SARS-CoV-2, the virus that causes COVID-19.</p>
<p>But as <a href="https://profiles.umassmed.edu/display/14945561">Nathaniel Hafer</a>, an expert in molecular medicine at UMass Chan Medical School, notes, the <a href="https://theconversation.com/whats-the-difference-between-a-pcr-and-antigen-covid-19-test-a-molecular-biologist-explains-170917">PCR test has weaknesses</a> – a PCR test can cost up to US$100 or more, and results can take several days to come through.</p>
<p>It’s important to note that all tests are a snapshot at the time of sample collection and are much more likely to be accurate when a person is infectious. So people are encouraged to take multiple tests 24 hours apart.</p>
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<strong>
Read more:
<a href="https://theconversation.com/whats-the-difference-between-a-pcr-and-antigen-covid-19-test-a-molecular-biologist-explains-170917">What's the difference between a PCR and antigen COVID-19 test? A molecular biologist explains</a>
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<h2>2. Why rapid tests are important – especially now</h2>
<p>Despite PCR tests being better at detecting low levels of the virus, the antigen tests can be particularly useful at a time when many people need to get tested.</p>
<p>As Hafer notes in a separate article for The Conversation, <a href="https://theconversation.com/rapid-tests-play-a-crucial-role-in-curbing-covid-19-infections-especially-as-people-gather-for-the-holidays-173207">rapid tests are</a> “a welcome tool in society’s fight against the COVID-19 pandemic.”</p>
<p>He advises readers to take a test, be it PCR or antigen, as soon as they show symptoms of COVID-19. And the same holds true whether someone is vaccinated or not.</p>
<p>“The faster you can determine if you have COVID-19, the sooner you can isolate yourself, which helps prevent transmission to others,” he writes.</p>
<p>And even if someone gets a negative antigen result, it shouldn’t be assumed that they are in the clear. Anyone showing symptoms would be advised to have a follow-up rapid or PCR test.</p>
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Read more:
<a href="https://theconversation.com/rapid-tests-play-a-crucial-role-in-curbing-covid-19-infections-especially-as-people-gather-for-the-holidays-173207">Rapid tests play a crucial role in curbing COVID-19 infections – especially as people gather for the holidays</a>
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<h2>3) So how do you use a home testing kit?</h2>
<p>One of the big benefits of the rapid test is that it can be performed at home – no need for a lab setting or skilled lab technicians.</p>
<p>Zoë McLaren, <a href="https://publicpolicy.umbc.edu/zoe-m-mclaren/">a public health policy expert at the University of Maryland, Baltimore County</a>, explained how readers should <a href="https://theconversation.com/over-the-counter-rapid-antigen-tests-can-help-slow-the-spread-of-covid-19-heres-how-to-use-them-effectively-166869">go about using their home test</a>.</p>
<p>First off, plan ahead. </p>
<p>“It’s important to have a plan for what to do based on the test results. If you get a positive result, immediately take precautions to slow transmission, such as self-isolating, letting close contacts know about the test result and reporting the case to health authorities,” McLaren writes. Even when presented with a negative result, caution is advised, “and, if you have symptoms or a known exposure, it’s a good idea to do a follow-up rapid antigen or PCR test just in case the first test was a false negative.”</p>
<p>A second rapid test performed 24-36 hours after the initial test can help detect coronavirus cases that may have been missed the first time around due to an insufficient viral load, writes McLaren.</p>
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<strong>
Read more:
<a href="https://theconversation.com/over-the-counter-rapid-antigen-tests-can-help-slow-the-spread-of-covid-19-heres-how-to-use-them-effectively-166869">Over-the-counter rapid antigen tests can help slow the spread of COVID-19 -- here's how to use them effectively</a>
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<h2>4) And if you still can’t get your hands on a rapid test?</h2>
<p>Despite the massive planned rollout of rapid tests announced by Biden, there may well still be difficulties finding a kit. </p>
<p>Loss of smell or taste can be an indicator of COVID-19 infection. <a href="https://foodscience.psu.edu/directory/jeh40">John Hayes</a> and <a href="https://www.nursing.psu.edu/directory/rice/">Cara Exten</a>, both of Penn State, recount how a graduate student’s mother discovered recently that she could neither smell nor taste her habitual cup of coffee. She quarantined and got a rapid test, which came back positive.</p>
<p>The fact that she confirmed her suspicions by use of an antigen test underscores a key point: If you have the slightest inkling that you may have COVID-19, or been in contact with someone who has, it is advisable to get tested to know for sure.</p>
<p>“Using loss of smell as a COVID-19 test is far from perfect. But because a daily smell check is very specific, instantaneous and quite literally free, it is a highly useful screening tool,” write Hayes and Exten.</p>
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Read more:
<a href="https://theconversation.com/daily-diy-sniff-checks-could-catch-many-cases-of-covid-19-150717">Daily DIY sniff checks could catch many cases of COVID-19</a>
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<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/174148/count.gif" alt="The Conversation" width="1" height="1" />
The Biden administration intends to distribute an additional 500 million at-home rapid COVID tests starting in January.Matt Williams, Senior International EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1732072021-12-10T13:37:47Z2021-12-10T13:37:47ZRapid tests play a crucial role in curbing COVID-19 infections – especially as people gather for the holidays<figure><img src="https://images.theconversation.com/files/436449/original/file-20211208-68670-ss0b36.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5973%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The key to rapid antigen testing is to test early in the course of COVID-19 infection, ideally several times 24 hours apart.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/negative-test-result-by-using-rapid-test-device-for-royalty-free-image/1322973278?adppopup=true"> VioletaStoimenova/E+ via Getty Images</a></span></figcaption></figure><p>As winter begins and the holidays are in full swing, the COVID-19 pandemic has entered another worrying phase. Emergence of the <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 variant</a>, along with <a href="https://www.npr.org/sections/health-shots/2021/11/16/1056232480/u-s-covid-cases-rising-holidays">increasing rates of infections</a>, have left many people unsure about their holiday plans. </p>
<p>On Dec. 2, 2021, President Joe Biden outlined a <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2021/12/02/fact-sheet-president-biden-announces-new-actions-to-protect-americans-against-the-delta-and-omicron-variants-as-we-battle-covid-19-this-winter/">series of actions</a> to respond to the COVID-19 pandemic, including making at-home COVID-19 rapid tests eligible for reimbursement by private insurance. Along with vaccination, <a href="https://doi.org/10.1093/cid/ciaa1508">testing remains one of the most effective ways</a> to track and reduce transmission of SARS-CoV-2, the virus that causes COVID-19.</p>
<p>Even though COVID-19 testing has become part of most people’s everyday conversation, many people still have questions about <a href="https://theconversation.com/whats-the-difference-between-a-pcr-and-antigen-covid-19-test-a-molecular-biologist-explains-170917">the difference</a> between antigen and PCR tests, including when and how to use them. </p>
<p>I’m a <a href="https://scholar.google.com/citations?user=OJ3tLoQAAAAJ&hl=en">molecular biologist</a> <a href="https://profiles.umassmed.edu/display/14945561">based at</a> UMass Chan Medical School. Since April 2020, I’ve been part of a team working on a <a href="https://www.nih.gov/research-training/medical-research-initiatives/radx/radx-programs">National Institutes of Health-funded program</a> called RADx Tech to help companies develop rapid tests to detect when a person is infected with COVID-19. </p>
<h2>How rapid antigen tests work</h2>
<p>Rapid <a href="https://theconversation.com/antigen-tests-for-covid-19-are-fast-and-easy-and-could-solve-the-coronavirus-testing-problem-despite-being-somewhat-inaccurate-137977">antigen tests</a> are designed to detect a portion of protein – known as an antigen – of SARS-CoV-2. First, you take a sample from your nose or mouth with a swab, as directed. You mix the sample with liquid that breaks apart the virus. You then apply the liquid to a test strip that has antibodies specific for SARS-CoV-2 painted on it in a thin line. Antibodies are Y-shaped proteins that recognize and bind to foreign substances such as antigens. If the antibodies bind to the virus proteins, or antigens, a colored line appears on the test strip, indicating the presence of SARS-CoV-2. </p>
<p>These tests are convenient because they are easy to use and provide results quickly, typically within <a href="https://theconversation.com/will-the-new-15-minute-covid-19-test-solve-us-testing-problems-145285">about 15 minutes</a>. Another benefit is that antigen tests can be relatively inexpensive, at around <a href="https://www.cvs.com/shop/home-health-care/home-tests/home-covid-test">US$10-$15 per test</a>. In contrast, PCR tests usually require laboratory equipment and technicians, take 12 hours to several days to get results and cost $100 or more, though there are many ways to get these tests free of charge. </p>
<p>In his announcement, President Biden also discussed plans to distribute 50 million free tests to community health care providers for people without insurance. People should check their local media outlets for information about when free rapid tests become available. In Colorado, free rapid tests have been available to <a href="https://covid19.colorado.gov/covid-19-testing-at-home">families with school-age children</a> for months. Be prepared to act quickly: In late November, 100,000 people signed up in less than 24 hours for <a href="https://www.wmur.com/article/free-at-home-covid-test-kits-new-hampshire/38387393">free antigen COVID tests</a> in New Hampshire.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People embrace next to a free COVID-19 rapid testing sign at Los Angeles International Airport." src="https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436275/original/file-20211208-137612-3rz6ve.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>
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<span class="caption">Los Angeles International Airport is offering free rapid COVID-19 tests to incoming international travelers.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/people-embrace-near-a-new-rapid-covid-19-testing-site-for-news-photo/1357066432?adppopup=true">Mario Tama/Getty Images News via Getty Images</a></span>
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<p>As of early December 2021, the <a href="https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-devices/in-vitro-diagnostics-euas-antigen-diagnostic-tests-sars-cov-2">Food and Drug Administration has authorized</a> about a dozen rapid antigen tests for SARS-CoV-2, which means these tests meet certain standards for performance and accuracy. </p>
<h2>When to use rapid tests</h2>
<p>If you have any symptoms of COVID-19, regardless of whether you’ve been vaccinated, you should <a href="https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html">get tested right away</a> with either a PCR or antigen test. </p>
<p>SARS-CoV-2 can spread very easily, even if you don’t have symptoms. The faster you can determine if you have COVID-19, the sooner you can isolate yourself, which helps prevent transmission to others. Early testing is also critical because new drugs like <a href="https://theconversation.com/could-oral-antiviral-pills-be-a-game-changer-for-covid-19-an-infectious-disease-physician-explains-why-these-options-are-badly-needed-169919">those from Merck and Pfizer</a> <a href="https://www.nytimes.com/2021/12/07/science/merck-pfizer-covid-pill-treatment.html">are most effective</a> if given early in the course of infection, soon after symptoms appear. </p>
<p>If you get a negative antigen test but still feel sick, it is possible that you received a false negative test. Isolate yourself away from others and contact your health care provider to discuss your symptoms. If you get a positive test, you should isolate yourself at home and contact your health care provider as soon as possible.</p>
<p>If you don’t have symptoms but <a href="https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html">have had close contact</a> with someone with COVID-19, what to do depends on your vaccine status. If you’re fully vaccinated, <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/fully-vaccinated-guidance.html">the CDC currently recommends</a> that you wait five to seven days after your exposure and then get a PCR or rapid antigen test. If you’re not fully vaccinated, <a href="https://www.cdc.gov/coronavirus/2019-ncov/your-health/quarantine-isolation.html">get tested right away</a>. If you don’t develop symptoms, you should still get retested five to seven days after your exposure.</p>
<p>Like many respiratory viruses, it takes several days for SARS-CoV-2 to build up in your body after exposure. During this early phase of infection, the amount of viral protein is relatively low, and a rapid test <a href="https://doi.org/10.1038/d41586-021-00332-4">may not detect</a> your infection. This is why <a href="https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.html">serial testing</a> over multiple days, with at least 24 hours between each test, is recommended for many antigen tests. Rapid antigen tests are most often accurate when a person is infectious, because that is when the highest amount of virus is in the respiratory tract.</p>
<p><a href="https://doi.org/10.1093/infdis/jiab337">Studies have shown</a> that serial antigen testing – typically two to three tests in one week – is on par with a single PCR test. Remember that a test is only a snapshot of your SARS-CoV-2 status at the time of the test. It’s possible, especially with antigen tests, to test negative during the early stages of infection.</p>
<h2>The future for at-home COVID-19 testing</h2>
<p>Despite all that we researchers have learned, there is still more to understand about the best way to use rapid tests. Our team is conducting several studies to fill these gaps. </p>
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<img alt="Closeup of a COVID-19 rapid test." src="https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436461/original/file-20211208-23-1xav8n9.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">The CDC recommends that fully vaccinated people wait five to seven days after a COVID-19 exposure before getting a PCR or rapid antigen test. Those not fully vaccinated should get tested right away.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/close-up-of-a-corona-rapid-test-coronavirus-rapid-royalty-free-image/1313528033?adppopup=true">lupmotion/iStock/Getty Images Plus via Getty Images</a></span>
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<p>One question we are studying with a program called <a href="https://covidtestaaypsi.org/learn-about-the-study.html">STOP COVID-19</a> is how people use home tests when their infection risk is low versus high. For instance, someone who wears a mask indoors and does not eat out at restaurants may be considered low risk, while someone who is not vaccinated and gathers with many people without masks is considered high risk. We are also interested in knowing whether people will adhere to a testing regimen when they have an exposure, and whether they will share their home test results with their local department of public health.</p>
<p>Another major question our team is studying is: How do antigen tests compare with PCR tests when it comes to detecting COVID-19 in people who are positive but have no symptoms? A separate nationwide study called <a href="https://covid19testus.org/research-studies/test-us-at-home/">Test Us at Home</a> is generating important data that will help us answer this question in the next few months.</p>
<p>Rapid antigen tests are a welcome tool in society’s fight against the COVID-19 pandemic. When used properly and in combination with other tools such as vaccination, mask-wearing and good hygiene, these actions can help limit the spread of SARS-CoV-2 this holiday season.</p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/173207/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathaniel Hafer receives funding from the National Institutes of Health via awards UL1TR001453 and U54HL143541.</span></em></p>Knowing when and how often to use rapid tests is key to getting an accurate picture of your COVID-19 status.Nathaniel Hafer, Assistant Professor of Molecular Medicine, UMass Chan Medical SchoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1704482021-10-27T19:13:27Z2021-10-27T19:13:27ZYour unvaccinated friend is roughly 20 times more likely to give you COVID<p>As lockdowns ease in New South Wales, Victoria and the ACT, and people return to work and socialising, many of us will be mixing more with others, even though a section of the community is still unvaccinated. </p>
<p>Many vaccinated people are concerned about the prospect of mixing with unvaccinated people. This mixing might be travelling on trains or at the supermarket initially. But also at family gatherings, or, in NSW at least, at pubs and restaurants <a href="https://www.smh.com.au/national/nsw/nsw-records-787-new-covid-19-cases-and-12-deaths-20210927-p58v1e.html">when restrictions ease further</a>, slated for December 1.</p>
<p>Some people are wondering, why would a vaccinated person care about the vaccine status of another person?</p>
<p>Briefly, it’s because vaccines reduce the probability of getting infected, which reduces the probability of a vaccinated person infecting someone else. And, despite vaccination providing excellent protection against severe disease, a small proportion of vaccinated people still require ICU care. Therefore some vaccinated people may have a strong preference to mix primarily with other vaccinated people.</p>
<p>But what exactly is the risk of catching COVID from someone who’s unvaccinated?</p>
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Read more:
<a href="https://theconversation.com/as-melbourne-cautiously-opens-up-today-what-lies-ahead-170206">As Melbourne cautiously opens up today, what lies ahead?</a>
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<h2>What’s the relative risk?</h2>
<p>Recent reports from the Victorian Department of Health find that unvaccinated people <a href="https://www.skynews.com.au/australia-news/coronavirus/watch-live-vic-health-officials-to-provide-covid19-update/news-story/863cdc24d57dd787251a8ccff26b5ec5">are ten times more likely to contract COVID</a> than vaccinated people.</p>
<p>We also know that vaccinated people are less likely to transmit the disease even if they become infected. The Doherty modelling from August <a href="https://www.doherty.edu.au/our-work/institute-themes/viral-infectious-diseases/covid-19/covid-19-modelling/modelling">puts the reduction at around 65%</a>, although more recent research has suggested a <a href="https://www.medrxiv.org/content/10.1101/2021.09.28.21264260v1">lower estimate for AstraZeneca</a>. Hence for this thought experiment, we’ll take a lower value of 50%.</p>
<p>As the prevalence of COVID changes over time, it’s hard to estimate an absolute risk of exposure. So instead, we need to think about risks in a relative sense. </p>
<p>If I were spending time with an unvaccinated person, then there’s some probability they’re infected and will infect me. However, if they were vaccinated, they’re ten times less likely to be infected and half as likely to infect me, following the numbers above.</p>
<p>Hence we arrive at a 20-fold reduction in risk when hanging out with a vaccinated person compared to someone who’s not vaccinated. </p>
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<img alt="" src="https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=829&fit=crop&dpr=1 754w, https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=829&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/428712/original/file-20211027-25-1jk3grg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=829&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p>The exact number depends on a range of factors, including the type of vaccine and time since vaccination. But, in Australia we can expect a large risk reduction when mixing with fully vaccinated people.</p>
<p>The calculation holds true whether you yourself are vaccinated or not. But being vaccinated provides a ten-fold reduction for yourself, which is on top of the risk reduction that comes from people you’re mixing with being vaccinated.</p>
<p>So, dining in an all-vaccinated restaurant and working in an all-vaccinated workplace presents a much lower infection risk to us as individuals, whether we are vaccinated or not. The risk reduction is around 20-fold, but as individuals, we need to consider whether that’s meaningful for our own circumstances, and for the circumstances of those we visit.</p>
<p>There are also added complexities, in that there are three vaccine brands available, and eligibility is still limited to those aged 12 and older. Although, we do know kids are <a href="https://theconversation.com/why-do-kids-tend-to-have-milder-covid-this-new-study-gives-us-a-clue-155555">less susceptible and less likely to show symptoms</a>.</p>
<p>However, as more information emerges, we can always update our estimates and think through the implications on the risk reduction. </p>
<h2>What about people who can’t be vaccinated?</h2>
<p>Some people haven’t been able to get vaccinated because they’re either too young or they have a medical exemption. Other people are immunocompromised and won’t get the same level of protection from two doses as the rest of the community. </p>
<p>Increasing our coverage across the board will help protect those who aren’t fully protected by vaccination (whether that’s by eligibility, medical reasons or choice).</p>
<p>Those at higher risk also enjoy the risk reduction if they’re able to mix primarily with vaccinated people.</p>
<p>And other choices we make can help reduce the risk of transmission when vaccination is impossible, for example, wearing masks, washing hands carefully, and so on.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1445296668715339779"}"></div></p>
<h2>Do rapid antigen tests help?</h2>
<p>Some people have proposed that frequent testing could be used to suppress COVID spread for those who are unwilling to be vaccinated.</p>
<p>Health minister Greg Hunt said Australians can <a href="https://www.abc.net.au/news/2021-09-28/covid-19-rapid-antigen-home-tests-available-from-november/100496776">buy rapid antigen tests from November 1</a>, so they can test themselves at home or before entering certain venues.</p>
<p>So how much does a rapid antigen test reduce risk to others?</p>
<p>To answer that question we need to consider test sensitivity.</p>
<p>Test sensitivity is the probability a rapid test will return a positive result, if the person is infected.</p>
<p>It’s challenging to get an accurate estimate. But rapid antigen tests are about <a href="https://www.tga.gov.au/sites/default/files/covid-19-rapid-antigen-self-tests-are-approved-australia-ifu-352250.pdf">80% as sensitive as a PCR test</a>, which are the traditional COVID tests we do that get sent off to a lab. The PCR tests themselves are <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251661">about 80% sensitive when it comes to identifying someone with COVID</a>.</p>
<p>So, if you did a rapid antigen test at home, it’s about 64% likely to pick up that you’re positive, if you did have COVID.</p>
<p>Therefore, rapid antigen tests can find about two-thirds of cases. If you’re going to a gathering where everyone has tested negative on a rapid antigen test, that’s a three-fold reduction in risk. </p>
<p>Even though rapid tests provide a reduction in risk, they don’t replace vaccines.</p>
<p>When used in conjunction with high levels of vaccination, rapid tests would provide improved protection for settings where we’re particularly keen to stop disease spread, such as <a href="https://www.theage.com.au/national/victoria/covid-scare-at-royal-children-s-as-victoria-records-1571-new-local-covid-19-cases-13-deaths-20211013-p58zh4.html">hospitals</a> and aged care facilities.</p>
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Read more:
<a href="https://theconversation.com/home-rapid-antigen-testing-is-on-its-way-but-we-need-to-make-sure-everyone-has-access-169362">Home rapid antigen testing is on its way. But we need to make sure everyone has access</a>
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<p>Consequently, despite the high efficacy of COVID vaccines, there are still reasons a vaccinated person would prefer to mix with vaccinated people, and avoid mixing with unvaccinated people. </p>
<p>This is particularly true for those at higher risk of severe disease, whether due to age or disability. Their baseline risk will be higher, so a 20-fold reduction in risk is more meaningful.</p><img src="https://counter.theconversation.com/content/170448/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Baker receives funding from The Australian Government Departments of Health and Foreign Affairs and Trade.</span></em></p><p class="fine-print"><em><span>Andrew Robinson receives funding for biosecurity research from the federal Department of Agriculture, Water and the Environment and New Zealand's Ministry for Primary Industries </span></em></p>Unvaccinated people are ten times more likely to contract COVID, and more likely to pass it on than vaccinated people.Christopher Baker, Research Fellow in Statistics for Biosecurity Risk, The University of MelbourneAndrew Robinson, CEO of the Centre of Excellence for Biosecurity Risk Analysis, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1668692021-09-10T16:53:10Z2021-09-10T16:53:10ZOver-the-counter rapid antigen tests can help slow the spread of COVID-19 – here’s how to use them effectively<figure><img src="https://images.theconversation.com/files/420358/original/file-20210909-8898-1dz0a4h.jpg?ixlib=rb-1.1.0&rect=36%2C27%2C5991%2C3913&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rapid antigen COVID-19 tests, designed for use at home, can show results in 15 minutes. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-at-home-using-a-nasal-swab-for-covid-19-royalty-free-image/1306947463?adppopup=true">Ellen Moran via Getty Images</a></span></figcaption></figure><p>The rise of the <a href="https://theconversation.com/what-are-covid-19-variants-and-how-can-you-stay-safe-as-they-spread-a-doctor-answers-5-questions-163697">highly transmissible delta variant</a> <a href="https://www.washingtonpost.com/nation/2021/09/07/covid-delta-variant-live-updates/">around the U.S.</a> has increased demand for <a href="https://theconversation.com/rapid-screening-tests-that-prioritize-speed-over-accuracy-could-be-key-to-ending-the-coronavirus-pandemic-143882">rapid antigen COVID-19 tests</a> that can be purchased from a pharmacy <a href="https://www.cdc.gov/coronavirus/2019-ncov/testing/self-testing.html">without a prescription</a>, used at home, school or work and that give results in 15 minutes. </p>
<p>On Sept. 9, 2021, the White House announced <a href="https://www.whitehouse.gov/covidplan/">several initiatives</a> to improve access to rapid antigen tests: It will use the <a href="https://www.cfr.org/in-brief/what-defense-production-act">Defense Production Act</a> to boost the production of tests, require retailers to sell rapid tests at cost, distribute free rapid tests to community health centers and food banks and expand free testing in pharmacies.</p>
<p>Rapid antigen testing makes it much easier to get tested for COVID-19, which helps detect infectious cases before they spread. But many people are still unsure of how best to use these tests and whether they are accurate enough to be useful.</p>
<p>There are several FDA-approved rapid tests on the market including <a href="https://www.abbott.com/corpnewsroom/diagnostics-testing/BinaxNOW-what-you-need-to-know.html">Abbott BinaxNow</a>, <a href="https://www.ellumehealth.com/products/consumer-products/covid-home-test/">Ellume</a> and <a href="https://quickvueathome.com/">Quidel QuickVue</a>. These cost as little as $7-12 each and can be used to test adults and children aged 2 and up, regardless of whether they have symptoms. </p>
<p>Rapid antigen tests have a big advantage over lab-based <a href="https://my.clevelandclinic.org/health/diagnostics/21462-covid-19-and-pcr-testing">PCR testing</a> in terms of speed and convenience. Getting results in 15 minutes rather than waiting a day or more for PCR test results means it’s possible to identify COVID-19 cases right away and take precautions to prevent transmission. Having rapid testing available <a href="https://theconversation.com/fda-authorized-first-over-the-counter-covid-19-test-useful-but-not-a-game-changer-152208">over-the-counter</a> means that a lot more people will get tested since the test is <a href="https://theconversation.com/will-the-new-15-minute-covid-19-test-solve-us-testing-problems-145285">easy to perform</a> and far more convenient than PCR testing. So rapid tests can catch a lot more COVID-19 cases overall than relying only on PCR testing.</p>
<p>As a <a href="https://twitter.com/ZoeMcLaren">health economist</a> who studies <a href="https://publicpolicy.umbc.edu/zoe-m-mclaren/">public health policy</a> to combat <a href="https://scholar.google.com/citations?hl=en&user=t6ZtGJwAAAAJ">infectious disease epidemics</a>, I know that making COVID-19 testing <a href="https://theconversation.com/making-coronavirus-testing-easy-accurate-and-fast-is-critical-to-ending-the-pandemic-the-us-response-is-falling-far-short-142366">accessible, accurate and fast</a> is critical to slowing transmission of the virus and helping everyone resume normal activities safely.</p>
<h2>How accurate are rapid antigen tests?</h2>
<p>Two types of rapid tests are used for detecting an active COVID-19 infection: rapid antigen tests that detect viral proteins using a paper strip and <a href="https://www.fda.gov/consumers/consumer-updates/coronavirus-disease-2019-testing-basics">rapid molecular tests</a> – including PCR – that detect viral genetic material using a medical device.</p>
<p>It’s important to remember that rapid antigen tests serve a different purpose than PCR testing, which is considered the gold standard even though it isn’t <a href="https://doi.org/10.1186/s12985-021-01489-0">100% accurate</a>. Rapid tests are designed to identify cases with a high enough viral load in the nasal passage to be transmissible – not to diagnose all COVID-19 cases. The <a href="https://www.abbott.com/corpnewsroom/diagnostics-testing/BinaxNOW-what-you-need-to-know.html">Abbott BinaxNOW</a> rapid antigen test may only detect <a href="https://www.fda.gov/media/147254/download">85%</a> of the positive cases detected by PCR tests. But the key is that <a href="https://doi.org/10.1093/infdis/jiaa802">published</a> <a href="https://doi.org/10.1128/JCM.00083-21">studies</a> found that they detect over 93% of cases that pose a transmission risk, which is what matters most for getting the pandemic under control. <a href="https://www.ellumehealth.com/products/consumer-products/covid-home-test/">Ellume</a> correctly <a href="https://www.fda.gov/media/144592/download">identifies 95%</a> of all positive cases, and <a href="https://quickvueathome.com/">Quidel QuickVue</a> accurately identifies <a href="https://www.fda.gov/media/146312/download">85%</a>. All three tests correctly identify upwards of 97% of all negative cases, regardless of symptoms.</p>
<figure class="align-center ">
<img alt="A photo of a rapid antigen test kit, available for home use." src="https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420363/original/file-20210909-23-ni8knw.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">One of the FDA-approved rapid antigen test kits, which can be used by adults and children age 2 and up.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/QuideltoBringQuickVueAt-HomeOTCCOVID-19TestsToCVSPharmacy/da5b1256e9b05b1af6c4960e08bd9060/photo?Query=home%20antigen%20test&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=18&currentItemNo=16">AP Photo/Business Wire</a></span>
</figcaption>
</figure>
<h2>How should rapid tests be used?</h2>
<p>Rapid antigen testing can be used in three ways to slow transmission. First, people can perform a rapid test when there is a suspected or known COVID-19 exposure. Second, rapid testing can provide an extra precaution before any activity with a higher risk of transmission, such as gatherings or travel. Third, it’s also possible to test on a regular basis – weekly, for instance, if enough tests are available – to catch cases that otherwise might go undetected.</p>
<p>It’s important to have a plan for what to do based on the test results. If you get a positive result, immediately <a href="https://www.cdc.gov/coronavirus/2019-ncov/testing/self-testing.html">take precautions</a> to slow transmission such as self-isolating, letting close contacts know about the test result and reporting the case to health authorities. <a href="https://www.fda.gov/media/147254/download">Less</a> <a href="https://www.fda.gov/media/144592/download">than</a> <a href="https://www.fda.gov/media/146312/download">3%</a> of negative cases receive false positives, but a second rapid test the following day or a PCR test can provide further confirmation if needed.</p>
<p>If you get a negative result from a rapid test, it means you are currently very unlikely to be infectious. A viral load that is too low to be detected by rapid antigen tests is almost surely <a href="https://www.nature.com/articles/d41586-020-02661-2">too low to be transmissible</a>. But it’s important not to let your guard down completely. The tests don’t detect 100% of infectious cases, so it’s possible for a small number to evade detection or for some cases to become infectious within hours after the test. For this reason, it may be a good idea to maintain other precautions. And, if you have symptoms or a known exposure, it’s a good idea to do a follow-up rapid antigen or PCR test just in case the first test was a false negative.</p>
<p>Think of the rapid antigen test as a snapshot in time: A negative test doesn’t necessarily mean you don’t have COVID-19. COVID-19 is <a href="https://www.nytimes.com/interactive/2020/10/02/science/charting-a-coronavirus-infection.html">most transmissible</a> when the viral load peaks, which is estimated to be <a href="https://doi.org/10.1016/S2666-5247(20)30172-5">within a week</a> after infection. Those who are infected but who take a rapid test before or after the viral load peak will get a negative rapid test result – meaning that even though they are infected, they are not currently infectious. One way to reduce the risk of false negatives is with “<a href="https://doi.org/doi:10.1001/jama.2021.5391">serial testing</a>,” where a second rapid test is performed 24-36 hours later to help catch any infectious cases that were missed with the first test.</p>
<h2>Will the new initiatives be enough?</h2>
<p>The <a href="https://www.whitehouse.gov/covidplan/">White House initiatives</a> to increase access to rapid testing are a critical step towards curbing case numbers. But <a href="https://www.whitehouse.gov/covidplan/">one free test</a> per person isn’t sufficient to help people resume normal activities safely. Authorizing additional inexpensive rapid tests through the <a href="https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-devices/in-vitro-diagnostics-euas">Food and Drug Administration</a> would further expand supply and reduce prices. </p>
<p>Making the COVID-19 vaccine free and easily accessible <a href="https://doi.org/10.1377/hlthaff.2021.00619">brought cases down</a> <a href="https://www.nytimes.com/2021/04/29/opinion/covid-exponential-decay.html">quickly</a> in the spring of 2021. Putting frequent rapid testing within reach for all <a href="https://www.theatlantic.com/health/archive/2020/08/how-to-test-every-american-for-covid-19-every-day/615217/">could do the same</a> now.</p>
<p><em>This article has been corrected to clarify that less than 3% of negative cases receive false positives.</em></p>
<p>[<em><a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-corona-important">The Conversation’s most important coronavirus headlines, weekly in a science newsletter</a></em>]</p><img src="https://counter.theconversation.com/content/166869/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zoë McLaren 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>Making rapid antigen tests for COVID-19 cheaper and more accessible can catch the infectious cases before they spread and help everyone resume normal activities safely.Zoë McLaren, Associate Professor of Public Policy, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1518622021-01-06T14:46:13Z2021-01-06T14:46:13ZCould a wristband or certificate allow you out of lockdown after a negative coronavirus test?<figure><img src="https://images.theconversation.com/files/375336/original/file-20201216-19-4f0djw.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C997%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Regular testing in return for a wristband.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/paper-wristband-mockup-event-bracelet-on-1173794866">Andrii Zastrozhnov/Shutterstock</a></span></figcaption></figure><p>An escalation of coronavirus cases and the discovery of two new variants in the UK has led to increasing restrictions and a new national lockdown. But could freedom passes based on negative test results – in the form of wristbands or certificates – offer a way to avoid placing restrictions on everyone? </p>
<p>On the back of a recent mass testing regime in Slovakia in October, after a second wave of coronavirus cases, the UK’s Behavioural Insights Team (BIT) <a href="https://www.bi.team/blogs/how-slovakia-tested-3-6-million-people-for-covid-19-in-a-single-weekend/">argued it could</a> provide easy recognition of those who have tested negative.</p>
<p><a href="https://www.bi.team/wp-content/uploads/2020/11/Slovakia-COVID-19-Population-Testing-Report.pdf">In Slovakia</a>, 3.6 million people were voluntarily tested (out of a population of 5.4 million) across one weekend and 38,000 new cases were identified – around 15 times the daily average identified under the country’s existing test and trace system. Slovakia used lateral flow tests, which take 15 minutes, with a reported sensitivity of 70%, meaning that three in ten positive samples go undetected. The BIT said a recent study suggested these tests picked up 50% of asymptomatic cases and apparently had apparently virtually no false positives. </p>
<p>Slovakia’s approach depended on providing the public with a strong incentive to get tested: the issuing of a government certificate for a negative test, and early release from a strict curfew. But what are the pitfalls of such a system – and could it be used in other countries with larger populations?</p>
<h2>‘Freedom pass’</h2>
<p>Under a voluntary mass testing scheme, people would have two options: get tested (assuming you’re not exempt) or not. If you choose to get tested, then whether or not you have symptoms the result is either positive or negative. Test positive and you would need to self-isolate with your household, test negative and you would receive the “freedom pass”. </p>
<p>Assuming that without a vaccine you don’t develop long-term immunity from SARS-CoV-2, <a href="https://theconversation.com/can-you-get-the-covid-19-coronavirus-twice-137309">you will still be at risk</a> of contracting it multiple times, even with a freedom pass. A freedom pass, then, could only be temporary and only remain valid with regular testing. </p>
<p>How frequently should one get tested? If you get a notification, for example via contact tracing, that you’ve come into contact with a person who has tested positive, does this invalidate your negative status? And would this still be the case if you didn’t report any symptoms?</p>
<h2>Incentives and accuracy</h2>
<p>It may be that the costs of getting tested would be too high, especially with a voluntary scheme. And if a limited degree of freedom of movement meant having to do multiple tests, then the costs of the scheme may outweigh the benefits (both for the people being tested and for the state).</p>
<p>There are additional issues regarding the test system, including accuracy of the tests themselves. <a href="https://theconversation.com/coronavirus-how-accurate-are-coronavirus-tests-135972">No test is 100% accurate</a>, although PCR swab tests are deemed more accurate than lateral flow tests, lateral flow tests are are quicker and more likely to be used for mass testing. Not only will some people test negative when they have the virus (a false negative) but people will also test positive when they don’t (a false positive). For a false positive, people will be told to self-isolate and be denied a certificate, losing their freedom of movement – despite the fact they do not have the virus. While the BIT reported virtually no false positives for the Slovakia test, it said a validation PCR test would be needed to confirm this.</p>
<figure class="align-center ">
<img alt="Hand in surgical glove holding a COVID-19 rapid test kit" src="https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375337/original/file-20201216-17-2h5w3u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A rapid test but there are still issues with accuracy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/positive-test-result-by-using-rapid-1668119515">Jarun Ontakrai/Shutterstock</a></span>
</figcaption>
</figure>
<p>In the case of a false negative, people may be infectious and unwittingly spreading the disease. Scaled up to the kinds of numbers involved in a mass testing programme in larger populations the number of potential false positives and false negatives could be very large. For both PCR and especially lateral flow tests, the optimal system would be confirmatory testing – testing someone more than once in a session to confirm their status either way and to reduce false results. In this case, a freedom pass would involve more than one test, as well as multiple testing to keep a valid pass.</p>
<p><a href="https://www.nhs.uk/conditions/coronavirus-covid-19/testing-and-tracing/antibody-test-to-check-if-youve-had-coronavirus/">Antibody tests</a> could be used to tell if you’ve previously had the virus. A freedom pass could be issued on the basis that you’d developed immunity and are less likely to transmit the virus – but we still don’t know <a href="https://theconversation.com/pfizer-vaccine-final-results-its-highly-protective-but-how-long-for-151966">how long people develop immunity</a> for, <a href="https://www.livescience.com/south-africa-variant-coronavirus-vaccines.html">whether for multiple variants</a> or just one virus type. And if someone tests negative for antibodies, do you still issue a freedom pass, or ask them to take additional tests for current infection?</p>
<p>Given these issues, what is the added value of a freedom pass under conditions in which the tests are voluntary, carry inaccuracies – or require a more costly complex and rigorous testing regime – especially in non-lockdown situations where freedom of movement exists?</p>
<p>Some standardised rapid testing could arguably be used for some venues (pubs, restaurants, sporting venues, workplaces and airports, for example), but this still clearly carries accuracy risks and costs – though the public may accept this for the sake of returning to some semblance of normality.</p>
<p>The only other alternative is to issue freedom passes to those that have had the vaccine. But inoculating populations will be a long process and some, such as those with immune compromised conditions, <a href="https://www.pulsetoday.co.uk/news/clinical-areas/immunology-and-vaccines/thousands-of-immunosuppressed-patients-to-test-covid-antibody-cocktail/">may not get access to a vaccine until much later</a>. This also assumes that we know how long of an immunity a vaccine gives, which to date we don’t. Getting vaccinated <a href="https://www.nytimes.com/2020/12/08/health/covid-vaccine-mask.html">doesn’t mean you can stop taking</a> social distancing measures and wearing mask. </p>
<h2>Failed interventions</h2>
<p>Although many public and private institutions now use behavioural techniques <a href="https://theconversation.com/eight-ways-to-reduce-the-chances-of-overeating-these-holidays-104230">to influence positive change</a>, the behavioural change enterprise disproportionately focuses on promoting successes.</p>
<p>In <a href="https://www.qmul.ac.uk/media/news/2020/se/nudges-fail-more-often-than-is-reported-experts-warn.html">a recent study</a> my colleagues and I showed that despite their widespread use, failed interventions are surprisingly common and lead to backfiring, making the behavioural problem worse. Examples we found included menus designed to encourage vegetarian food choices that led to fewer meals being ordered by people who more regularly ate vegetarian food, and how use of smaller packaging to reduce consumption could actually lead to an increase.</p>
<p>Even if interventions such as a wristbands were implemented, there is a risk that overall this could result in fewer people getting tested or some walking around with the virus and some stuck at home without it. This would be classified, based on our published work, as a backfiring effect.</p>
<p>While I can see the motivation behind the idea and suggested behavioural interventions, the design and deployment of a similar programme in the UK requires much more consideration. As the authors of <a href="https://www.bmj.com/content/371/bmj.m4436">a recent article in the BMJ</a> on mass testing wrote: “Nobody’s freedom or behaviour should be made contingent on having had a novel rapid test. It is premature to offer testing as the route to individuals’ release from restrictions.”</p><img src="https://counter.theconversation.com/content/151862/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Magda Osman 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>Slovakia successfully launched mass testing and certification after a second wave of coronavirus.Magda Osman, Reader in Experimental Psychology, Queen Mary University of LondonLicensed as Creative Commons – attribution, no derivatives.