tag:theconversation.com,2011:/us/topics/vaccine-preventable-diseases-79314/articlesVaccine-preventable diseases – The Conversation2024-03-21T20:24:31Ztag:theconversation.com,2011:article/2262052024-03-21T20:24:31Z2024-03-21T20:24:31ZMeasles is highly contagious, but vaccine-preventable: A primer on recent outbreaks, transmission, symptoms and complications, including ‘immune amnesia’<figure><img src="https://images.theconversation.com/files/583049/original/file-20240320-16-lkngkh.jpg?ixlib=rb-1.1.0&rect=0%2C135%2C3962%2C2913&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A measles virus particle. Measles is one of the most contagious pathogens known.</span> <span class="attribution"><span class="source">(CDC and NIAID)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Canada is seeing a resurgence of measles, with cases in the first quarter of 2024 already far surpassing the total for all of 2023. There were <a href="https://www.canada.ca/en/public-health/services/publications/diseases-conditions/measles-rubella-surveillance/2023/week-52.html">12 cases last year</a>, and more than three times that number so far in 2024, with 38 reported as of March 19. </p>
<p>Most of these cases (28) <a href="https://www.quebec.ca/en/health/health-issues/a-z/measles/measles-outbreak">are in Québec</a>, and <a href="https://www.publichealthontario.ca/-/media/Documents/M/24/measles-ontario-epi-summary.pdf?rev=c082f5ae0c6c446f9624d47b7e3c8535&sc_lang=en">eight are in Ontario</a>, while <a href="https://www.saskhealthauthority.ca/news-events/news/measles-exposure-risk-saskatoon">Saskatchewan</a> and <a href="https://news.gov.bc.ca/releases/2024HLTH0026-000274">British Columbia</a> have each reported one case. </p>
<p>As an immunologist with a focus on host-microbe interactions and antiviral immunity, I have been following recent measles outbreaks. </p>
<h2>Symptoms and complications</h2>
<p>Measles (also known as rubeola) is a serious but vaccine-preventable disease caused by an RNA virus of the family <a href="https://www.britannica.com/science/paramyxovirus-virus-family">Paramyxoviridae</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A child seen from behind with a red rash all over his skin" src="https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=720&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=720&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=720&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=905&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=905&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583046/original/file-20240320-24-qx59sq.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=905&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Measles rash appears on the face before spreading downward to other areas of the body.</span>
<span class="attribution"><span class="source">(U.S. Centers for Disease Control)</span></span>
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</figure>
<p>Measles usually begins with fever, runny nose, conjunctivitis (red watery eyes), sore throat and coughing. These can be initially mistaken for common cold or flu.</p>
<p>However, these non-specific signs and symptoms are typically followed by clinical manifestations that are characteristic of measles. These include Koplik spots (tiny white specks with bluish-white centres in the inner lining of the cheeks), and subsequently a <a href="https://www.cdc.gov/measles/symptoms/signs-symptoms.html">measles rash</a> appearing on the face before spreading downward to other areas of the body.</p>
<p>In most cases, measles resolves on its own. However, <a href="https://www.mayoclinic.org/diseases-conditions/measles/symptoms-causes/syc-20374857">severe complications</a> may arise, especially in immunocompromised individuals. <a href="https://www.cdc.gov/globalhealth/measles/about/index.html">Complications</a> can include pneumonia, encephalitis (brain inflammation and swelling), blindness, deafness and permanent neurological consequences. When measles occurs during pregnancy, it can result in miscarriage, premature labour, stillbirth, birth defects or even fetal death. The most severe cases of measles can be fatal. </p>
<p>Also of note, infection with the measles virus can weaken the immune system for months or years, increasing the risk of infections with a wide range of microbes. While measles-associated immunosuppression has been documented for decades, we are only beginning to decipher its underlying mechanisms. For example, a phenomenon called “<a href="https://doi.org/10.1038/s41467-018-07515-0">immune amnesia</a>” is thought to contribute, at least partially, to unrelated infections in the aftermath of measles.</p>
<h2>What is immune amnesia?</h2>
<p>The naturally occurring (wild-type) strains of measles virus can target, infect and kill memory B and T lymphocytes, which are instrumental to antimicrobial defence. This is because one of the three measles virus receptors, called CD150, happens to be abundantly present on the surface of these lymphocytes.</p>
<p>Long-lived memory cells, which accumulate as a result of immunizations and infections over time, remain in a poised state to mount rapid and rigorous recall responses when we re-encounter microbes. B cells orchestrate the production of antibodies that neutralize extracellular microbes, and T cells work to destroy infected cells. Therefore, when people lose their precious memory cells to measles, the immune system is set back to a default mode, as if it has never seen any microbes or vaccines in the past.</p>
<p>To add insult to injury, <a href="https://doi.org/10.1093/infdis/jiaa407">measles virus may also eliminate “memory-like” innate T cells</a>, which also express CD150, thus removing yet another potent weapon from our antimicrobial arsenal. Therefore, collectively, the ability of measles virus to find and kill memory and memory-like lymphocytes can lead to adaptive and <a href="https://doi.org/10.1371/journal.ppat.1009071">innate immune amnesia</a>, rendering a measles patient or survivor prone to many opportunistic infections.</p>
<h2>How does measles spread and how contagious is it?</h2>
<figure class="align-right ">
<img alt="microscopic image of a virus" src="https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583047/original/file-20240320-20-nv4olv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Microscopic view of a measles virus particle (red).</span>
<span class="attribution"><span class="source">(CDC and NIAID)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Measles virus spreads easily through airborne droplets released by infected people when they breathe, talk, laugh, cough or sneeze. In addition, measles virus infectious particles can remain active in the air and on contaminated surfaces for up to two hours.</p>
<p>Measles virus is one of the most contagious respiratory pathogens known, with <a href="https://doi.org/10.1016/S1473-3099(17)30307-9">each person with measles passing on their infection to 12 to 18 other people</a> in a susceptible population. Measles virus is more transmissible than influenza viruses and SARS-CoV-2 variants.</p>
<h2>How effective are measles vaccines?</h2>
<p>Measles vaccines are safe, affordable and extremely effective. According to the World Health Organization (WHO), <a href="https://www.who.int/news-room/fact-sheets/detail/measles">measles claimed 2.6 million lives each year before 1963</a> when a measles vaccine became available. Since then, widespread immunization programs have saved millions of lives, including an estimated 56 million just between 2000 and 2021.</p>
<p>Measles vaccines contain a live measles virus strain that has been attenuated so that it does not inflict harm; yet, it is sufficient to generate protective immune responses. </p>
<p>The measles-mumps-rubella (MMR) vaccine or the measles-mumps-rubella-varicella (MMRV) vaccine is routinely administered to children in <a href="https://www.canada.ca/en/public-health/services/diseases/measles/health-professionals-measles.html">two doses</a>, with a first dose being given after the first birthday, typically between 12-15 months of age, followed by a booster dose recommended after 18 months of age and before attending school. This should afford lifelong protection against measles in most people. </p>
<p>According to the United States Centers for Disease Control and Prevention (CDC), one and two doses of the MMR vaccine are <a href="https://www.cdc.gov/vaccines/vpd/mmr/public/index.html">93 per cent and 97 per cent effective</a> in preventing measles, respectively. </p>
<p>Teens and adults should also <a href="https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-12-measles-vaccine.html#">remain up to date with regard to measles immunization</a> since measles can affect anyone. There are blood tests that can be ordered by health-care providers to determine immunity to measles. </p>
<p>The MMR vaccine can be <a href="https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-12-measles-vaccine.html#">given at any time</a> during one’s lifespan, but the MMRV vaccine is authorized in Canada only between one and 13 years of age.</p>
<h2>Why are measles cases returning?</h2>
<p>Recent years have witnessed a rise in measles outbreaks within and outside Canada. This is primarily due to an alarming decline in measles vaccination caused by <a href="https://theconversation.com/measles-global-increase-in-cases-likely-driven-by-covid-pandemic-182250">delayed childhood immunizations amid COVID-19</a> lockdowns, vaccine hesitancy <a href="https://theconversation.com/measles-outbreak-why-are-anti-vaxxers-risking-a-public-health-crisis-116334">creating vulnerable societal pockets</a>, anti-vaccine sentiments and <a href="https://time.com/6564694/measles-antivaccine-misinformation/">digital misinformation</a> spread through online social media, and the resumption of global travel post-COVID.</p>
<p>Measles outbreaks occur soon after <a href="https://doi.org/10.1001/jama.2020.20895">herd immunity</a> is compromised. Herd immunity is achieved when an adequately large proportion of a population becomes immune to a specific pathogen through prior infections or vaccination. As a result, the probability of an infectious case encountering a susceptible person drops dramatically. </p>
<p>For measles, the necessary <a href="https://www.who.int/news/item/23-11-2022-nearly-40-million-children-are-dangerously-susceptible-to-growing-measles-threat">threshold for herd immunity is 95 per cent</a>. This means when 95 per cent of people in a population are immune, the remaining five per cent (including newborns, unvaccinated or undervaccinated children and immunodeficient people who cannot receive a measles vaccine) are also indirectly protected since the risk of measles virus transmission is significantly minimized.</p>
<p>By receiving two doses of a measles vaccine, one protects not only themselves but also the vulnerable members of their community. The only way to avoid measles and its serious complications, including proneness to a broad spectrum of unrelated infections, is to vaccinate widely, to engage those who are hesitant to have their children immunized in a respectful dialogue, and to educate the public regarding the unparalleled benefits of measles vaccines.</p>
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Read more:
<a href="https://theconversation.com/how-better-conversations-can-help-reduce-vaccine-hesitancy-for-covid-19-and-other-shots-159321">How better conversations can help reduce vaccine hesitancy for COVID-19 and other shots</a>
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<p>It is also crucial to isolate infected individuals for four days after the appearance of a measles rash to prevent measles virus transmission to others.</p>
<p>In Canada, measles has been <a href="https://www.canada.ca/en/public-health/services/diseases/measles/surveillance-measles.html">a nationally notifiable disease</a> since 1924 (except between 1959 and 1968), and the Canadian Measles and Rubella Surveillance System (CMRSS) ensures the weekly collection of measles data from every province and territory, including zero report submissions.</p><img src="https://counter.theconversation.com/content/226205/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mansour Haeryfar 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>Canada is seeing a surge in measles cases. Find out what measles is, why it’s returning to Canada, and how people can protect themselves and others.Mansour Haeryfar, Professor of Immunology, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170592023-12-13T13:35:34Z2023-12-13T13:35:34ZHealth misinformation is rampant on social media – here’s what it does, why it spreads and what people can do about it<figure><img src="https://images.theconversation.com/files/564379/original/file-20231207-23-75o0yn.jpg?ixlib=rb-1.1.0&rect=62%2C26%2C5904%2C4070&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Media literacy is more essential than ever. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/myth-fake-news-and-facts-vector-illustration-royalty-free-illustration/1358189151?phrase=social+media+misinformation&searchscope=image%2Cfilm&adppopup=true">Wanlee Prachyapanaprai/iStock via Getty Images Plus</a></span></figcaption></figure><p>The global anti-vaccine movement and vaccine hesitancy that <a href="https://doi.org/10.1093/cid/ciaa433">accelerated during the COVID-19 pandemic</a> show no signs of abating.</p>
<p>According to a survey of U.S. adults, Americans in October 2023 were <a href="https://www.annenbergpublicpolicycenter.org/vaccine-confidence-falls-as-belief-in-health-misinformation-grows/">less likely to view approved vaccines as safe</a> than they were in April 2021. As vaccine confidence falls, health misinformation continues to spread like wildfire on social media and in real life.</p>
<p>I am a <a href="https://www.bu.edu/sph/profile/monica-wang/">public health</a> <a href="https://scholar.google.com/citations?user=5g6xyEMAAAAJ&hl=en">expert</a> in <a href="https://doi.org/10.1093/abm/kaaa088">health misinformation</a>, <a href="https://doi.org/10.1093/tbm/ibac096">science communication</a> and <a href="https://doi.org/10.1891/9780826180148">health behavior change</a>.</p>
<p>In my view, we cannot underestimate the <a href="https://doi.org/10.2105/AJPH.2020.305905">dangers of health misinformation</a> and the need to understand why it spreads and what we can do about it. Health misinformation is defined as any health-related claim that is false based on current scientific consensus. </p>
<h2>False claims about vaccines</h2>
<p>Vaccines are the No. 1 topic of misleading health claims. Some <a href="https://doi.org/10.3389%2Ffmicb.2020.00372">common myths about vaccines</a> include: </p>
<ul>
<li><p><strong>Their supposed link with human diagnoses of autism</strong>. Multiple studies have <a href="https://doi.org/10.1016/j.vaccine.2014.04.085">discredited this claim</a>, and it has been firmly refuted by the <a href="https://www.who.int/groups/global-advisory-committee-on-vaccine-safety/topics/mmr-vaccines-and-autism">World Health Organization</a>, the <a href="https://www.nationalacademies.org/based-on-science/vaccines-do-not-cause-autism">National Academies of Sciences, Engineering and Medicine</a>, the <a href="https://publications.aap.org/patiented/article-abstract/doi/10.1542/peo_document599/82016/Vaccines-Autism-Toolkit">American Academy of Pediatrics</a> and the <a href="https://www.cdc.gov/vaccinesafety/concerns/autism.html">Centers for Disease Control and Prevention</a>.</p></li>
<li><p><strong>Concerns with the COVID-19 vaccine leading to infertility</strong>. This connection has been debunked through a <a href="https://doi.org/10.1016%2Fj.vaccine.2022.09.019">systematic review and meta-analysis</a>, one of the most robust forms of synthesizing scientific evidence.</p></li>
<li><p><strong>Safety concerns about vaccine ingredients, such as thimerosal, aluminum and formaldehyde</strong>. Extensive studies have shown these ingredients are safe when used in <a href="https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/vaccine-myth-fact">the minimal amounts contained in vaccines</a>.</p></li>
<li><p><strong>Vaccines as medically unnecessary to protect from disease</strong>. The development and dissemination of vaccines for life-threatening diseases such as smallpox, polio, measles, mumps, rubella and the flu has saved <a href="https://doi.org/10.1073%2Fpnas.1704507114">millions of lives</a>. It also played a critical role in historic <a href="https://doi.org/10.1073/pnas.1413559111">increases in average life expectancy</a> – from 47 years in 1900 in the U.S. to 76 years in 2023. </p></li>
</ul>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CX9WyO4s4kA","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>The costs of health misinformation</h2>
<p>Beliefs in such myths have come at the highest cost. </p>
<p>An estimated 319,000 COVID-19 deaths that occurred between January 2021 and April 2022 in the U.S. <a href="https://globalepidemics.org/vaccinations/">could have been prevented</a> if those individuals had been vaccinated, according to a data dashboard from the Brown University School of Public Health. Misinformation and disinformation about COVID-19 vaccines alone have cost the U.S. economy an estimated <a href="https://doi.org/10.1093/tbm/ibac096">US$50 million to $300 million per day</a> in direct costs from hospitalizations, long-term illness, lives lost and economic losses from missed work.</p>
<p>Though vaccine myths and misunderstandings tend to dominate conversations about health, there is an <a href="https://doi.org/10.2196%2F17187">abundance of misinformation</a> on social media surrounding diets and eating disorders, smoking or substance use, chronic diseases and medical treatments. </p>
<p>My team’s research and that of others show that social <a href="https://doi.org/10.2196/43961">media platforms have become go-to sources</a> <a href="https://doi.org/10.2196%2F17917">for health information</a>, especially among adolescents and young adults.
However, many people are not equipped to maneuver the maze of health misinformation.</p>
<p>For example, an analysis of Instagram and TikTok posts from 2022 to 2023 by The Washington Post and the nonprofit news site The Examination found that the food, beverage and dietary supplement industries paid dozens of registered dietitian influencers to <a href="https://www.washingtonpost.com/wellness/2023/09/13/dietitian-instagram-tiktok-paid-food-industry/">post content promoting diet soda, sugar and supplements</a>, reaching millions of viewers. The dietitians’ relationships with the food industry were not always made clear to viewers. </p>
<p>Studies show that health misinformation spread on social media results in <a href="https://doi.org/10.1016%2Fj.vaccine.2022.09.046">fewer people getting vaccinated</a> and can also increase the risk of other health dangers such as <a href="https://www.scientificamerican.com/article/how-a-weight-loss-trend-on-tiktok-might-encourage-eating-disorders/">disordered eating</a> and <a href="https://doi.org/10.18297/tce/vol1/iss1/16">unsafe sex practices and sexually transmitted infections</a>. Health misinformation has even bled over into animal health, with a 2023 study finding that 53% of dog owners surveyed in a nationally representative sample report being <a href="https://doi.org/10.1016/j.vaccine.2023.08.059">skeptical of pet vaccines</a>.</p>
<h2>Health misinformation is on the rise</h2>
<p>One major reason behind the spread of health misinformation is <a href="https://www.pewresearch.org/science/2023/11/14/americans-trust-in-scientists-positive-views-of-science-continue-to-decline/">declining trust in science</a> and <a href="https://www.pewresearch.org/politics/2023/09/19/public-trust-in-government-1958-2023/">government</a>. Rising political polarization, coupled with <a href="https://doi.org/10.1080%2F08964289.2019.1619511">historical medical mistrust</a> among communities that have experienced and continue to experience <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4194634/">unequal health care treatment</a>, exacerbates preexisting divides.</p>
<p>The lack of trust is both fueled and reinforced by the way misinformation can spread today. Social media platforms allow people to <a href="https://doi.org/10.2105%2FAJPH.2020.305905">form information silos</a> with ease; you can curate your networks and your feed by unfollowing or muting contradictory views from your own and liking and sharing content that aligns with your existing beliefs and value systems. </p>
<p>By tailoring content based on past interactions, social media algorithms can unintentionally <a href="https://doi.org/10.1016/j.tics.2023.06.008">limit your exposure</a> to diverse perspectives and generate a fragmented and incomplete understanding of information. Even more concerning, a study of misinformation spread on Twitter analyzing data from 2006 to 2017 found that <a href="https://doi.org/10.1126/science.aap9559">falsehoods were 70% more likely to be shared</a> than the truth and spread “further, faster, deeper and more broadly than the truth” across all categories of information.</p>
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<figcaption><span class="caption">The average kindergarten student sees about 70 media messages every day. By the time they’re in high school, teens spend more than a third of their day using media.</span></figcaption>
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<h2>How to combat misinformation</h2>
<p>The lack of robust and standardized regulation of misinformation content on social media places the difficult task of discerning what is true or false information on individual users. We scientists and research entities can also do better in communicating our science and rebuilding trust, as my colleague and I have <a href="https://www.bu.edu/articles/2023/rebuilding-public-trust-in-science/">previously written</a>. I also provide <a href="https://doi.org/10.1001/jamapediatrics.2023.5282">peer-reviewed recommendations</a> for the important roles that parents/caregivers, policymakers and social media companies can play. </p>
<p>Below are some steps that consumers can take to identify and prevent health misinformation spread: </p>
<ul>
<li><p><strong>Check the source.</strong> Determine the credibility of the health information by checking if the source is a reputable organization or agency such as the <a href="https://www.who.int">World Health Organization</a>, the <a href="https://www.nih.gov">National Institutes of Health</a> or the <a href="https://www.cdc.gov">Centers for Disease Control and Prevention</a>. Other credible sources include an established medical or scientific institution or a peer-reviewed study in an academic journal. Be cautious of information that comes from unknown or biased sources.</p></li>
<li><p><strong>Examine author credentials.</strong> Look for qualifications, expertise and relevant professional affiliations for the author or authors presenting the information. Be wary if author information is missing or difficult to verify.</p></li>
<li><p><strong>Pay attention to the date.</strong> Scientific knowledge by design is meant to evolve as new evidence emerges. Outdated information may not be the most accurate. Look for recent data and updates that contextualize findings within the broader field. </p></li>
<li><p><strong>Cross-reference to determine scientific consensus.</strong> Cross-reference information across multiple reliable sources. Strong consensus across experts and multiple scientific studies supports the validity of health information. If a health claim on social media contradicts widely accepted scientific consensus and stems from unknown or unreputable sources, it is likely unreliable. </p></li>
<li><p><strong>Question sensational claims.</strong> Misleading health information often uses sensational language designed to provoke strong emotions to grab attention. Phrases like “miracle cure,” “secret remedy” or “guaranteed results” may signal exaggeration. Be alert for potential conflicts of interest and sponsored content.</p></li>
<li><p><strong>Weigh scientific evidence over individual anecdotes.</strong> Prioritize information grounded in scientific studies that have undergone rigorous research methods, such as randomized controlled trials, peer review and validation. When done well with representative samples, the scientific process provides a reliable foundation for health recommendations compared to individual anecdotes. Though personal stories can be compelling, they should not be the sole basis for health decisions. </p></li>
<li><p><strong>Talk with a health care professional.</strong> If health information is confusing or contradictory, seek guidance from trusted health care providers who can offer personalized advice based on their expertise and individual health needs. </p></li>
<li><p><strong>When in doubt, don’t share.</strong> Sharing health claims without validity or verification contributes to misinformation spread and preventable harm.</p></li>
</ul>
<p>All of us can play a part in responsibly consuming and sharing information so that the spread of the truth outpaces the false.</p><img src="https://counter.theconversation.com/content/217059/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Wang receives funding from the National Institutes of Health. </span></em></p>Studies show that health misinformation on social media has led to fewer people getting vaccinated and more lives lost to COVID-19 and other life-threatening diseases.Monica Wang, Associate Professor of Public Health, Boston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2074782023-07-07T12:28:11Z2023-07-07T12:28:11ZTuberculosis on the rise for first time in decades after COVID-19 interrupted public health interventions and increased inequality<figure><img src="https://images.theconversation.com/files/535903/original/file-20230705-15-j8nls.jpg?ixlib=rb-1.1.0&rect=323%2C0%2C6192%2C4067&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tuberculosis is a dangerous bacterial infection of the lungs.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/shot-of-a-young-man-coughing-while-hes-sick-royalty-free-image/1358069629?phrase=Coughing&adppopup=true">Moyo Studio/E+ via Getty Images</a></span></figcaption></figure><p>Before SARS-CoV-2, the virus that causes COVID-19, spread across the world in 2020, tuberculosis was responsible for more deaths globally than any other <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022">infectious disease</a>. But thanks to <a href="https://doi.org/10.15585%2Fmmwr.rr6901a1">targeted public health efforts</a> in the U.S. and globally, tuberculosis cases had been <a href="https://doi.org/10.15585/mmwr.mm7212a1">steadily falling for decades</a>. </p>
<p>I am an <a href="https://scholar.google.com/citations?user=ECuj1XkAAAAJ&hl=en&oi=ao">infectious disease clinician and public health practitioner</a> who has been caring for underserved communities in the U.S. for more than two decades. </p>
<p>During the pandemic, it at first appeared that, as with many other common illnesses like the flu, <a href="https://www.who.int/news/item/27-10-2022-tuberculosis-deaths-and-disease-increase-during-the-covid-19-pandemic">COVID-19 prevention efforts reduced tuberculosis cases</a>, too. But tuberculosis numbers have quickly climbed back up to <a href="https://doi.org/10.1016/S1473-3099(22)00500-X">pre-pandemic levels</a>, marking the first time in decades that <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022/tb-disease-burden/2-2-tb-mortality">cases and deaths have risen globally</a>.</p>
<p>The pandemic not only interrupted important health interventions for tuberculosis, it also caused a <a href="https://doi.org/10.3389/fpubh.2020.00241">decrease in social and economic opportunities</a> for marginalized people around the globe. Together, these effects appear to have put a serious dent in the fight against tuberculosis. </p>
<p><iframe id="9iPuv" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/9iPuv/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Tuberculosis before and during COVID-19</h2>
<p>Tuberculosis is a contagious bacterial infection of the lungs that is normally spread <a href="https://doi.org/10.5588%2Fijtld.22.0685">through the air</a>. Most tuberculosis <a href="https://www.cdc.gov/tb/topic/basics/tbinfectiondisease.htm">infections are asymptomatic</a> and not contagious. </p>
<p>About 5% to 10% of <a href="https://doi.org/10.15585%2Fmmwr.rr6901a1">infected individuals</a> develop active tuberculosis, which is characterized by cough, fever, decreased appetite and weight loss. If left untreated, tuberculosis is a very contagious and dangerous disease that <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022">can result in death</a>. </p>
<p>Total estimated tuberculosis infections globally have been <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022/tb-disease-burden/2-1-tb-incidence">falling for years</a>. The lowest number, 10.1 million cases, occurred in 2020, according to the World Health Organization. 2021 saw a significant increase in infections, to 10.5 million, the first rise in more than a decade. Global tuberculosis deaths followed a similar pattern, reaching a low point of an estimated 1.4 millions deaths in 2019, then rising to <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022/tb-disease-burden/2-2-tb-mortality">1.5 million in 2020 and 1.6 million in 2021</a>.</p>
<p>The number of confirmed cases of tuberculosis – infections detected through direct testing – tells a different part of the story. As testing efforts have improved, confirmed cases have been rising globally to a <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022/covid-19-and-tb">peak in 2019</a>. As the coronavirus disrupted lives in 2020, confirmed cases of tuberculosis fell significantly before <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022">quickly rising again in 2021</a>.</p>
<p>A similar pattern <a href="https://www.cdc.gov/media/releases/2022/s0324-tuberculosis-covid-19.html">played out in the U.S.</a> There was a sharp drop in confirmed cases in 2020 – mostly driven by lack of testing – followed by a <a href="https://www.cnn.com/2023/03/23/health/tuberculosis-2022-cdc-report/index.html">sharp rise back to pre-pandemic levels</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An man standing in a hospital next to a sign with TB Ward written on it." src="https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535922/original/file-20230705-19-ap4h7k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Places with limitations in access to health care, economic mobility and social stability – including many parts of sub-Saharan Africa and India – carry the highest numbers of tuberculosis cases every year.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-indian-patient-who-has-been-diagnosed-with-tubercolosis-news-photo/937243906?adppopup=true">Shammi Mehra/AFP via Getty Images</a></span>
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<h2>Tuberculosis is a social disease</h2>
<p>Tuberculosis is a preventable disease, thanks to <a href="https://www.cdc.gov/tb/topic/basics/vaccines.htm">effective vaccines</a>, testing and treatments. But millions of people around the world still suffer from this disease, not because of a lack of medical knowledge, but because of <a href="https://doi.org/10.2105%2FAJPH.2010.199505">persistent social inequities</a>.</p>
<p>Unequal access to economic opportunities, limited health care, poor sanitation, crowded living conditions, malnutrition and <a href="https://doi.org/10.1016/s1473-3099(09)70282-8">illnesses such as diabetes or HIV</a> are all <a href="https://doi.org/10.5588%2Fijtld.12.0385">associated with increased risk of tuberculosis</a>.</p>
<p>In the U.S. in 2021, <a href="https://doi.org/10.1001/jama.2023.4899">racial and ethnic minority groups</a> accounted for more than 85% of tuberculosis cases, with <a href="https://www.cdc.gov/tb/topic/populations/healthdisparities/default.htm">71% of cases occurring in persons born outside the U.S.</a> </p>
<h2>Increased inequality causing more tuberculosis</h2>
<p>Even as the world witnessed a rapid <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022/covid-19-and-tb">decline in confirmed cases in 2020</a>, experts were worried that interruption of prevention and treatment efforts might <a href="https://www.reuters.com/article/us-health-tuberculosis-who-idUSKBN26Z1VJ">result in a rise in tuberculosis</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sign announced an emergency room is closed because of the pandemic." src="https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=598&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=598&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=598&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=751&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=751&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535925/original/file-20230705-17-7oyx2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=751&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The COVID-19 pandemic disrupted many medical systems and increased inequality more broadly, leading to an increase in tuberculosis cases globally.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-exterior-of-the-mt-sinai-south-nassau-hosptials-news-photo/1355659170?adppopup=true">J. Conrad Williams Jr./Newsday RM via Getty Images</a></span>
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<p>These fears were warranted. <a href="https://www.nytimes.com/2020/08/03/health/coronavirus-tuberculosis-aids-malaria.html">Many health experts</a>, along with the U.S. Centers for Disease Control and Prevention, have confirmed the pandemic disrupted access to tuberculosis testing and diagnosis. It is likely that many cases were missed because of the interruption of tuberculosis control activities, since funding, resources and staff were reassigned to assist in <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022">COVID-19 control efforts</a>. Additionally, during health encounters, similarities in symptoms between COVID-19 and tuberculosis may have led to <a href="https://www.cdc.gov/media/releases/2022/s0324-tuberculosis-covid-19.html">missed diagnoses</a>.</p>
<p>The drop in confirmed cases seems to be, in large part, driven by a lack of testing. The rapid increase since the pandemic, and especially the rise in deaths, confirms that progress made in tuberculosis control over the past 20 years has stalled, slowed or reversed. These two troubling trends are also almost certainly connected to the increase in <a href="https://doi.org/10.3389/fpubh.2020.00241">inequality brought about by the pandemic</a>.</p>
<p>The existence of multigenerational households, overcrowding in low-income neighborhoods, lack of paid sick leave, inability to shield from the pandemic, use of public transportation and lack of health insurance all converged to heighten the risk of both COVID-19 and tuberculosis among the most vulnerable people. </p>
<p>Of course, the pandemic is not the only factor that has increased human hardship – and therefore, tuberculosis – in recent years. For example, Ukraine now has one of the <a href="https://doi.org/10.1016/S1473-3099(23)00220-7">world’s highest tuberculosis disease burdens</a> as a result of Russia’s invasion and the resulting harm to Ukraine’s medical, social and economic systems. Ongoing conflicts in other parts of the world, energy shortages and the effects of climate change and associated impacts on food security are expected to worsen the broader <a href="https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022">social and political determinants of tuberculosis</a>. </p>
<p>There are many <a href="https://doi.org/10.1371%2Fjournal.pntd.0000256">neglected diseases of poverty</a>, and tuberculosis is a great example of how social forces produce human disease. With an estimated <a href="https://doi.org/10.1183/13993003.00655-2019">one-third of the world’s population at risk for tuberculosis</a> today, fostering social justice interventions to reduce health inequities is a critically important step to relieving the global medical burden of this relentless disease.</p><img src="https://counter.theconversation.com/content/207478/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Carlos Franco-Paredes 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>Tuberculosis is a preventable and curable disease, yet before the pandemic, it killed more people than any other infectious disease.Carlos Franco-Paredes, Associate Faculty Mycobacteria Research Laboratories, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2055152023-06-15T06:09:04Z2023-06-15T06:09:04ZMeasles and whooping cough outbreaks in South Africa: a sign of low vaccination coverage, experts warn<figure><img src="https://images.theconversation.com/files/530906/original/file-20230608-12385-a4sqhf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Caregivers are conflicted about vaccinating their children. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>The concentrated global effort to use vaccination as a public health intervention began in <a href="https://www.who.int/news-room/fact-sheets/detail/immunization-coverage">1974</a>. Since then, vaccination has changed our lives. Worldwide, in the decades 2000-2020, childhood vaccination led to the reduction of deaths in children under 5 by 50% to <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31891-9/fulltext">5.4 million deaths</a> per year. Vaccination currently averts more than <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32657-X/fulltext">5 million deaths</a> each year <a href="https://www.youtube.com/watch?app=desktop&v=vfAcG_ur27g">worldwide</a>. These are deaths that would have been caused by measles, whooping cough, tetanus, polio, diphtheria, pneumonia, rotavirus diarrhoea, and other <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32657-X/fulltext">vaccine-preventable diseases</a>. But in recent months there have been numerous outbreaks of these diseases. Scientists from the South African Medical Research Council explain why these diseases continue to threaten children’s health in the country.</em></p>
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<h2>The country currently has outbreaks of several diseases. What are they?</h2>
<p>There is an increased spread of <a href="https://www.nicd.ac.za/south-african-measles-outbreak-update-2023-9-june-2023/">measles</a> in South Africa now.</p>
<p>Measles is a highly infectious disease that spreads through droplets. It is the second most frequently reported disease outbreak in Africa after cholera. It accounts for 11.5% of all reported disease <a href="https://www.cambridge.org/core/journals/epidemiology-and-infection/article/infectious-disease-outbreaks-in-the-african-region-overview-of-events-reported-to-the-world-health-organization-in-2018/A504999B25CBA5E179B951FABB8CFE53">epidemics on the continent</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-a-history-of-the-measles-virus-and-why-its-so-tenacious-130262">Explainer: a history of the measles virus and why it's so tenacious</a>
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<p>Children who have not been vaccinated against measles are at high risk of the disease and its complications. These include pneumonia, brain damage, and death. Measles is one of the most dangerous but preventable childhood diseases. Up to <a href="http://www.samj.org.za/index.php/samj/article/view/6196/4933">10% of children</a> under five years of age who develop measles die from complications of the disease. </p>
<p>An effective vaccine against measles has been available for decades. A child requires two doses of the measles vaccine to develop protective immunity against the disease. The two doses of the measles vaccine are given at 6 and 12 months of age in South Africa. At least 95% coverage of 2 doses of the measles vaccine is required for herd immunity against <a href="https://www.who.int/news-room/fact-sheets/detail/measles">measles</a> and protect those who aren’t able to get vaccinated.</p>
<p>Another highly infectious disease that has recently seen an increase in cases in South Africa is pertussis, also referred to as <a href="https://www.nicd.ac.za/an-increase-in-pertussis-cases-13-dec-2022/">whooping cough</a>. Pertussis spreads easily from person to person through droplets produced by coughing or sneezing. Complications of whooping cough include pneumonia, seizures, brain damage, and death. The best way to prevent pertussis is through <a href="https://www.who.int/health-topics/pertussis#tab=tab_2">vaccination</a>. </p>
<h2>These diseases are preventable. What’s behind the spread?</h2>
<p>The resurgence of vaccine-preventable diseases in South Africa is due to immunity gaps caused by low vaccination coverage. A <a href="https://www.health.gov.za/wp-content/uploads/2022/03/National-EPI-Coverage-Survey_Final-full-report-Dec-2020.pdf">national survey</a> conducted from July to December 2019 found that only 81% of children had received all their vaccine doses scheduled up to 12 months of age in South Africa. This percentage has increased only slightly to <a href="https://www.who.int/data/gho/data/themes/topics/immunization-coverage">82%</a> since then, according to estimates from the World Health Organization (WHO) and the United Nations Children Fund (UNICEF).</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/south-africas-immunisation-record-risks-being-dented-by-anti-vaccination-views-153549">South Africa's immunisation record risks being dented by anti-vaccination views</a>
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<h2>What’s the cause of the gaps in immunisation?</h2>
<p>Over the last two years, routine immunisation services and coverage of essential childhood vaccines have been disrupted. And many <a href="https://www.who.int/news/item/24-04-2023-global-partners-announce-a-new-effort-the-big-catch-up-to-vaccinate-millions-of-children-and-restore-immunization-progress-lost-during-the-pandemic">catch-up vaccination efforts</a> have been postponed due to the COVID-19 pandemic. This has led to an increase in the number of children who are unvaccinated or under-vaccinated. </p>
<p>The country’s low vaccination coverage is due to both <a href="https://doi.org/10.1002/14651858.CD013265.pub2">supply and demand issues</a>. These relate to the provision of vaccines and the population’s decision to vaccinate. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6378923/pdf/CD013265.pdf">Structural barriers</a> such as vaccine availability and access to health facilities are well known to reduce vaccination coverage. </p>
<p>Research also <a href="https://www.tandfonline.com/doi/pdf/10.1080/21645515.2018.1460987?needAccess=true&role=button">suggests</a> that social and psychological factors, such as concerns about the safety and efficacy of vaccines, influence decisions around vaccination. Some caregivers are conflicted about vaccinating their children. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/unpacking-parents-reasons-for-not-vaccinating-their-children-why-it-matters-171527">Unpacking parents' reasons for not vaccinating their children: why it matters</a>
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<p><a href="https://journalofethics.ama-assn.org/sites/journalofethics.ama-assn.org/files/2018-05/mhst1-1201.pdf">Vaccine hesitancy</a> represents a motivational state of being conflicted about or opposed to vaccination. Evidence from several studies conducted in South Africa has shown a significant <a href="https://www.tandfonline.com/doi/pdf/10.1080/14760584.2021.1949291">increase in vaccine hesitancy</a>. This has had a dramatic impact on routine immunisation services and ultimately reduced vaccine coverage over the years.</p>
<h2>What steps can be taken to close these gaps?</h2>
<p>Globally, many initiatives exist to improve childhood immunization, especially in low- and middle-income countries. Within the context of the Immunization Agenda 2030 (IA2030) programme, WHO, UNICEF and Gavi, are launching the <a href="https://www.who.int/news/item/24-04-2023-global-partners-announce-a-new-effort-the-big-catch-up-to-vaccinate-millions-of-children-and-restore-immunization-progress-lost-during-the-pandemic">“Big Catch-Up”</a> initiative. This initiative aims to support countries like South Africa to plan and implement intensified efforts to bolster immunisation. It has three main objectives: </p>
<ul>
<li><p>to reach children who missed vaccination during 2020-2022 for catch-up vaccination</p></li>
<li><p>to restore vaccination coverage to the last best coverage in 2019 </p></li>
<li><p>to strengthen immunisation programmes to reach the under-vaccinated and unvaccinated children. </p></li>
</ul>
<p><a href="https://bmjopen.bmj.com/content/bmjopen/12/11/e058258.full.pdf">Interventions</a> that are focused on improving the healthcare system include cold-chain infrastructure improvements to ensure availability and access to vaccines. Some other <a href="https://www.tandfonline.com/doi/epdf/10.1080/21645515.2016.1221553?needAccess=true&role=button">interventions</a> that can improve uptake of vaccines include using motivational posters or flyers, sending reminders (messages or letters), and material or monetary incentives to caregivers or pay-for-performance schemes for healthcare workers providing vaccinations to children. </p>
<p>Informing and providing education to caregivers and healthcare workers has also been <a href="https://bmjopen.bmj.com/content/bmjopen/12/11/e058258.full.pdf">effective</a> increasing vaccination in children in cases where parents were hesitant. However, not enough research is done on interventions to dispel misinformation and misconception regarding immunisation, which is one of the leading causes of vaccine hesitancy.</p><img src="https://counter.theconversation.com/content/205515/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duduzile Ndwandwe receives funding from the South African Medical Research Council. She is affiliated with Eh! Woza, a non-profit Organization for public engagement. </span></em></p><p class="fine-print"><em><span>Charles Shey Wiysonge and Lindi Mathebula do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Over the last two years, routine immunisation services and coverage of essential childhood vaccines have been disrupted.Charles Shey Wiysonge, Director, Cochrane South Africa, South African Medical Research CouncilDuduzile Ndwandwe, Deputy Director and Specialist Scientist , South African Medical Research CouncilLindi Mathebula, Project Manager, South African Medical Research CouncilLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2050692023-06-05T14:25:30Z2023-06-05T14:25:30ZHepatitis B is a life-threatening liver infection – our machine learning tool could help with early detection<figure><img src="https://images.theconversation.com/files/529046/original/file-20230530-15-9wf3s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>More than <a href="https://www.who.int/news-room/fact-sheets/detail/hepatitis-b">296 million people</a> worldwide live with hepatitis B, a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). Most don’t know they are infected, so they don’t get medical care. Clinical care improves the patient’s outcome and can prevent them from infecting others. </p>
<p>Early detection of HBV-infected patients could therefore improve patient prognosis and stop transmission within populations. </p>
<p>The recommended test for HBV is an <a href="https://apps.who.int/iris/bitstream/handle/10665/254621/9789241549981-eng.pdf">enzyme immunoassay</a>. It detects the hepatitis B surface <a href="https://www.britannica.com/science/antigen">antigen</a> – a substance that is a sign of the presence of the virus in the person’s body. </p>
<p>But these chemical tests are very <a href="https://apps.who.int/iris/bitstream/handle/10665/254621/9789241549981-eng.pdf">expensive</a> and need dedicated facilities. They are generally out of reach for people in low-resource settings, where laboratories are few and isolated. Clinicians in these settings work with limited resources against <a href="https://www.afro.who.int/news/91-million-africans-infected-hepatitis-b-or-c">a silent killer</a> that may not show obvious symptoms for decades until the liver is severely damaged. </p>
<p>Part of the solution for public health challenges like this may lie in <a href="https://theconversation.com/what-machine-learning-can-offer-nigerias-healthcare-system-163593">machine learning</a>. This refers to the ability of computers to make sense of large amounts of information – and to build on their own “knowledge”.</p>
<p>We are among a group of researchers at the <a href="https://nceph.anu.edu.au/">Australian National University</a> who study machine learning and infectious disease. Our <a href="https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-021-06800-6">earlier research</a> found that the prevalence of HBV in Nigeria was high (9.5%, where anything above 8% is considered high). And the levels of infection varied significantly across geopolitical zones. </p>
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Read more:
<a href="https://theconversation.com/hepatitis-b-in-nigeria-fresh-data-to-inform-prevention-and-care-173018">Hepatitis B in Nigeria: fresh data to inform prevention and care</a>
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<p>Access to affordable testing was a problem in the country. So we <a href="https://www.nature.com/articles/s41598-023-30440-2">developed a tool</a> to help clinicians detect hepatitis B infections earlier.</p>
<p>Using Nigerian patient data, we developed an algorithm that learns from the patient data, identifies patterns, and makes intelligent decisions to provide alerts and detection of a patient’s HBV infection status. The aim is to enhance clinical decision-making and improve patient outcomes. Enabling earlier care should give millions of people a better quality of life and help reduce HBV prevalence.</p>
<h2>How did we do the work?</h2>
<p>To build this tool, we worked closely with colleagues at the <a href="https://nimr.gov.ng/">Nigerian Institute of Medical Research</a>. They provided access to data from 916 anonymous patients, in an ethically approved manner. The institute is Nigeria’s foremost medical research institute and it hosts a dedicated hepatitis B clinic.</p>
<p>We used the results of normal blood tests that measure red and white blood cells, salts, enzymes and other blood chemicals, along with results of tests for hepatitis B. Routine blood tests can be very useful in facilitating early diagnosis if the subtle interactions between measurements can be spotted. Patterns of interactions may be a signal of disease. But it’s easy to miss them. </p>
<p>Using the data, we trained an algorithm to identify pathology markers that predict a patient’s HBV infection status. One reason machine learning is so powerful is that it does not require humans to tell the computer which features to identify. Our algorithm sifts through the data to find patterns that are common to patients with HBV infection and then match those patterns in people it has not seen before. </p>
<p>Once validated, the algorithm can be integrated into routine clinical workflow in a real-world clinical setting, as an intelligent decision support system. This will help detect HBV infections earlier, without resorting to expensive immunoassay. </p>
<h2>What did we find?</h2>
<p>For the 916 people in <a href="https://www.nature.com/articles/s41598-023-30440-2">our study</a>, our algorithm could reliably make an intelligent call to accurately predict those infected with HBV. Its discrimination threshold was 90% — indicating that the algorithm was highly accurate.</p>
<p>We then translated this into a user-friendly, web-accessible app to use in further studies. The decision support tool, <a href="https://hepblivetest.app/">Hep B LiveTest</a>, was designed as a prototype.</p>
<p>The tool found that a combination of two enzymes, patient age and white blood cell count was the strongest predictor of HBV infection. The two enzymes are aspartate aminotransferase and alanine aminotransferase. When levels of these in the blood are high, it may indicate potential liver damage. Serum albumin, a liver function marker, was also identified as an important predictive marker of infection.</p>
<p>A <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jmv.23609">study of Chinese patients</a> showed trends similar to those suggested by our algorithm. Alanine aminotransferase and serum albumin were the most prominent predictors.</p>
<h2>What’s next?</h2>
<p>It is important to recognise the limitations of machine learning. Before a tool like this is put to work in routine clinical practice, it needs to be validated using diverse data. </p>
<p>Our machine learning tool was trained with data from Nigeria, so its performance may be limited to that setting. We are in the process of training our algorithm with more data from other sources and validating its robustness in other settings. This will inform how broadly applicable our algorithm is and how well it might work in other populations – particularly in settings with a low prevalence of hepatitis B infections.</p>
<p>Though our machine learning tool is only a first test, the results are highly encouraging. <a href="https://news.un.org/en/story/2021/07/1096592">A person dies from viral hepatitis B every 30 seconds</a>. We hope to put our system to work soon in the urgent fight against this <a href="https://www.nature.com/articles/d44148-022-00128-2">vaccine-preventable disease</a>. </p>
<p>We believe that machine learning has a role in enhancing the World Health Organization’s targets of <a href="https://apps.who.int/iris/bitstream/handle/10665/246177/WHO-HIV-2016.06-eng.pdf?sequence=1&isAllowed=y">eliminating viral hepatitis as a public health problem by 2030</a>.</p><img src="https://counter.theconversation.com/content/205069/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett A. Lidbury receives funding from the Quality Use of Pathology Program (QUPP) - Commonwealth Department of Health. He holds a Fellowship with the Royal College of Pathologists of Australasia (RCPA) Faculty of Science, and collaborates with the RCPA Quality Assurance Programme (RCPAQAP). </span></em></p><p class="fine-print"><em><span>Busayo I. Ajuwon 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>Machine learning can spot patterns in patient data and help detect hepatitis B earlier, which could save lives.Busayo I. Ajuwon, Research Scientist, Australian National UniversityBrett A. Lidbury, Associate ProfessorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1905652022-09-21T13:11:00Z2022-09-21T13:11:00ZCOVID pandemic created immunisation gaps in Africa. Over half a million children are at risk<figure><img src="https://images.theconversation.com/files/485537/original/file-20220920-18-c12wfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Routine immunisation has resulted in diseases like measles being drastically reduced.</span> <span class="attribution"><span class="source">Laszlo Mates/shutterstock</span></span></figcaption></figure><p>The COVID pandemic exposed the fault lines in health systems and national routine immunisation programmes around the world. </p>
<p>A <a href="https://www.who.int/news/item/15-07-2022-covid-19-pandemic-fuels-largest-continued-backslide-in-vaccinations-in-three-decades">recent</a> World Health Organization (WHO) report showed that the pandemic fuelled the largest sustained decline in childhood vaccine coverage rates. </p>
<p>These declines threaten to undo the exceptional efforts made in preventing and controlling the devastating burden of vaccine preventable diseases globally. Routine immunisation has prevented <a href="https://ourworldindata.org/vaccination#global-decline-in-vaccine-preventable-diseases">two to three million deaths</a> yearly. Of the lives saved, <a href="https://www.afro.who.int/health-topics/immunization#:%7E:text=Immunization%20currently%20prevents%20over%204,every%20year%20because%20of%20vaccines.">800,000</a> were in the Africa region. Routine immunisation has led to a drastic reduction in diseases like neonatal tetanus and measles. And bacterial meningitis (type A) and polio have virtually been eliminated across the continent. </p>
<p>The repercussions of the pandemic on routine immunisation programmes in the African region are yet to be fully realised. What we do know so far is that the pandemic has resulted in substantial disruptions to national routine immunisation programmes. As a result, the continent is seeing an increased number of outbreaks of vaccine preventable diseases. </p>
<p>African countries had nearly eliminated the deadly form of meningitis type A. But a four-month-long meningitis outbreak was reported in the <a href="https://www.afro.who.int/news/meningitis-outbreak-democratic-republic-congo-declared-over#:%7E:text=Meningitis%20outbreak%20in%20Democratic%20Republic%20of%20the%20Congo%20declared%20over,-24%20December%202021&text=Brazzaville%2FKinshasa%20%E2%80%93%20The%20Democratic%20Republic,and%20205%20deaths%20were%20recorded.">Democratic Republic of Congo</a> in 2021. It accounted for 2,665 cases, claiming 205 lives. This resurgence has been <a href="https://www.voanews.com/a/covid-threatening-resurgence-of-deadly-meningitis-in-africa/6736714.html?s=09">linked</a> with the suspension of meningitis vaccination campaigns at the height of the COVID pandemic. In February 2022, <a href="https://www.afro.who.int/news/malawi-declares-polio-outbreak">Malawi</a> reported its first wild case of poliovirus type 1 in 30 years. A second case followed in <a href="https://www.afro.who.int/countries/mozambique/news/mozambique-confirms-wild-poliovirus-case">Mozambique</a> three months later. The outbreaks sparked <a href="https://doi.org/10.1016/s1473-3099(22)00269-9">mass polio vaccination campaigns</a> across southern Africa. </p>
<p>UNICEF and the WHO have <a href="https://www.who.int/news/item/27-04-2022-unicef-and-who-warn-of--perfect-storm--of-conditions-for-measles-outbreaks--affecting-children">warned</a> of the heightened risk for measles outbreaks, given widening immunisation gaps. </p>
<p>Currently, Zimbabwe is contending with a devastating measles outbreak. Within five months, there have been <a href="https://twitter.com/MoHCCZim/status/1567416772512415744?s=20&t=JslCu5Tki9SCpNLaJXclwg">6,551 confirmed measles cases</a> and <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/zimbabwe-measles-outbreak-death-toll-rises-685-health-ministry-2022-09-03/">704 related deaths</a>. </p>
<p>These emerging outbreaks are a matter of great concern. They call for urgent and sustained public health interventions. Unless these are put in place, the compounding effects of the pandemic could derail regional progress towards the global <a href="https://www.who.int/teams/immunization-vaccines-and-biologicals/strategies/ia2030">immunisation targets</a> that secure the health and wellbeing of infants and children.</p>
<p>The resurgence of deadly vaccine preventable diseases underscores the importance of maintaining high vaccination coverage rates. Children everywhere must have access to all the recommended lifesaving vaccines they need. The disruptions observed during the COVID pandemic also highlight the importance of establishing resilient health systems. Systems must be able to withstand acute and prolonged shocks while delivering essential health services like immunisation programmes. </p>
<h2>Immunisation before COVID</h2>
<p>It is important to contextualise the performance of routine immunisation programmes within the African region. Even before the pandemic, the African region was already contending with a precarious situation. </p>
<p>For one, an <a href="https://www.afro.who.int/publications/investment-case-vaccine-preventable-diseases-surveillance-african-region-2020-2030">estimated</a> 30.7 million children under five continue to suffer from vaccine preventable diseases. These include rotavirus diarrhoea, pneumonia, pertussis and measles. Of these children, more than 520,000 die each year because of poor access to essential immunisation services. </p>
<p>The continent’s health systems have to manage on average <a href="https://www.afro.who.int/health-topics/disease-outbreaks/outbreaks-and-other-emergencies-updates">150 cases of disease outbreaks and other public health emergencies</a> every year. These range from armed conflicts to climate-related disasters (including flooding, drought, and famine) and disease outbreaks. National routine immunisation programmes have had to function in this context. </p>
<h2>The pandemic widened immunisation gaps</h2>
<p>On the continent the pandemic has substantially disrupted national routine immunisation programmes. In many countries health systems were forced to divert limited resources to combat the pandemic. This often left immunisation services vulnerable. </p>
<p>At the height of the pandemic, <a href="https://doi.org/10.1016/S2214-109X(21)00512-X">several countries reported</a> having to suspend vaccination services. There were disruptions to vaccine supply chains which led to stockouts. The number of people taking up immunisation services declined due to restrictions on public gathering. Many people also feared being exposed to the virus at health facilities. </p>
<p>A good measure of the COVID-related disruptions to immunisation programmes is the coverage of the three doses of the diphtheria-tetanus-pertussis (DTP3) vaccine. The <a href="https://www.who.int/data/gho/data/indicators/indicator-details/GHO/diphtheria-tetanus-toxoid-and-pertussis-(dtp3)-immunization-coverage-among-1-year-olds-(-)">WHO</a> uses the coverage of DTP3 to monitor access to immunisation services and measure the performance of broader health systems. </p>
<p>The <a href="https://www.who.int/news/item/15-07-2022-covid-19-pandemic-fuels-largest-continued-backslide-in-vaccinations-in-three-decades">WHO report</a> shows that the COVID-19 pandemic contributed to a general decline in DTP3 coverage globally – irrespective of economic power or income level. </p>
<p>In Africa, national immunisation programmes in several countries maintained optimal performance, achieving <a href="https://immunizationdata.who.int/index.html">DTP3 coverage rates above 90%</a>. These included Algeria, Botswana, Burkina Faso, Burundi, Ghana, Kenya, Malawi, Mauritius, Namibia, Sierra Leone, Uganda and Zambia. </p>
<p>Of concern, however, are the 29 countries that recorded coverage of less than 90%, creating substantial immunisation gaps.</p>
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<img alt="" src="https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485610/original/file-20220920-3689-nsysvx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&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">DTP vaccine coverage in many African countries was below the WHO’s 90% threshold.</span>
<span class="attribution"><span class="source">Data Source: WHO, https://immunizationdata.who.int/index.html</span></span>
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<p>The increased misinformation and disinformation during the pandemic also led to some decline in public trust and confidence in immunisation services. This has significantly affected vaccine demand. </p>
<h2>Charting a way forward</h2>
<p>The pandemic provides useful lessons on the importance of continuously strengthening health systems and “crisis-proofing” national routine immunisation programmes. </p>
<p>COVID-19 has been a catalyst for renewed political interest in immunisation programmes. But this must be followed up with regional solidarity to re-prioritise routine immunisation in the national and regional public health agendas. </p>
<p>National governments will have the responsibility to secure and sustain donor funding while increasing domestic financial commitments that will fill the funding gaps for national immunisation programmes. This is in line with the <a href="https://www.afro.who.int/health-topics/immunization/the-addis-declaration-immunization">declarations they have endorsed</a>. </p>
<p>But most importantly, there’s a need to intensify demand for vaccines and immunisation programmes. This is critical to build back public confidence and trust in vaccines and immunisation services in a post-COVID world.</p><img src="https://counter.theconversation.com/content/190565/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edina Amponsah-Dacosta does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The pandemic has disrupted national immunisation programmes. As a result, the African continent is seeing more outbreaks of vaccine preventable diseases.Edina Amponsah-Dacosta, Postdoctoral Research Fellow, Vaccines for Africa Initiative, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1881572022-08-09T18:52:00Z2022-08-09T18:52:00ZNZ children face a ‘perfect storm’ of dangerous diseases as immunisation rates fall<figure><img src="https://images.theconversation.com/files/478217/original/file-20220809-18-orxjcu.jpg?ixlib=rb-1.1.0&rect=15%2C15%2C5226%2C3473&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>Routine childhood immunisations have dropped so dramatically globally during the COVID-19 pandemic that the World Health Organization and <a href="https://www.unicef.org/press-releases/WUENIC2022release">UNICEF</a> are raising the alarm. </p>
<p>Internationally, <a href="https://www.who.int/news/item/15-07-2022-covid-19-pandemic-fuels-largest-continued-backslide-in-vaccinations-in-three-decades">25 million children</a> in 2021 alone have missed out on life-saving vaccinations. This is the <a href="https://www.who.int/news/item/15-07-2022-covid-19-pandemic-fuels-largest-continued-backslide-in-vaccinations-in-three-decades">largest sustained drop</a> in childhood immunisation in a generation. </p>
<p>In Aotearoa New Zealand, we are seeing a similarly concerning trend. The decline in childhood immunisation resulting in low overall coverage is now putting our tamariki (children) at real risk of preventable disease, especially with national borders open again.</p>
<p>The country is not alone in suffering collateral damage to normal childhood immunisation programmes due to the COVID-19 pandemic. But while the decline may be worrying, all is not lost. </p>
<h2>Risk of disease outbreaks</h2>
<p>Immunisation coverage at six months of age <a href="https://www.health.govt.nz/our-work/preventative-health-wellness/immunisation/immunisation-coverage/national-and-dhb-immunisation-data">has fallen</a> in New Zealand from a high of around 80% in early 2020 to 67% by June 2022, and as low as 45% for Māori. </p>
<p>This is important because immunisation coverage at six months is used as a marker for timely receipt of lifesaving <a href="https://www.health.govt.nz/our-work/preventative-health-wellness/immunisation/new-zealand-immunisation-schedule">government-funded vaccines</a>, including for whooping cough (pertussis), diphtheria, polio, pneumococcal disease and rotavirus.</p>
<p>For example, <a href="https://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/whooping-cough">whooping cough</a> (pertussis), a particularly serious illness for babies, is a very real concern. Aotearoa has seen a <a href="https://surv.esr.cri.nz/PDF_surveillance/PertussisRpt/2019/PertussisReportMay2019.pdf">pertussis resurgence</a> every three to four years, meaning we are due an increase in cases at a time when we also have low vaccine coverage.</p>
<p>Additionally, these declines in immunisation coverage and subsequent risk of infection are especially important to consider now, as international travel picks up.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=572&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=572&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=572&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=719&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=719&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478239/original/file-20220809-16-8awc3f.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=719&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="attribution"><span class="source">NZ Ministry of Health</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>The return of ‘old’ diseases</h2>
<p>Polio, a viral disease that can cause paralysis, disappeared from Aotearoa thanks to immunisation, with the Western Pacific region declared <a href="https://www.scielosp.org/pdf/bwho/2000.v78n12/1375-1375/en">polio free</a> in 2000. As some parts of the world have yet to eradicate it, however, we still vaccinate children against polio. </p>
<p>A <a href="https://www.statnews.com/2022/07/29/u-s-polio-case-tied-to-viruses-detected-in-u-k-israel-suggesting-silent-spread">recent case</a> in an unvaccinated young man in New York shows how the virus can travel and re-emerge – even in developed, polio-free countries.</p>
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Read more:
<a href="https://theconversation.com/diphtheria-is-back-in-australia-heres-why-and-how-vaccines-can-prevent-its-spread-186348">Diphtheria is back in Australia, here's why – and how vaccines can prevent its spread</a>
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<p>Likewise, <a href="https://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/diphtheria">diphtheria</a> is a rare but serious disease that causes breathing problems and can also lead to nerve paralysis and heart failure, with 5% to 10% of people with the disease dying. </p>
<p>Until widespread immunisation after the 1940s, diphtheria was a common cause of childhood death, and we haven’t seen it in Aotearoa for decades. But diphtheria has recently been detected in Australia in two unvaccinated children. </p>
<p>With New Zealand’s <a href="https://covid19.govt.nz/international-travel/who-can-enter-new-zealand/">borders fully open</a> since July 31, we run the risk of both these “old” diseases being imported and causing problems for our under-immunised tamariki and their whānau.</p>
<h2>A perfect measles storm</h2>
<p>The significant measles outbreak of 2019 serves as a warning. More than 2,000 <a href="https://www.health.govt.nz/system/files/documents/pages/health-report-measles-review-2020.pdf">people were infected and 700 hospitalised</a>, with the largest case numbers in Auckland.</p>
<p>Fiji, Tonga and Samoa also saw outbreaks, with Samoa <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30053-0/fulltext">particularly devastated</a> by more than 5,000 cases and more than 80 deaths, mostly in young children. </p>
<p>The severity of this outbreak <a href="https://www.health.govt.nz/system/files/documents/pages/health-report-measles-review-2020.pdf">could have been prevented</a> because the combined measles, mumps and rubella (MMR) vaccine is highly effective. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-most-challenging-phase-of-the-omicron-outbreak-is-yet-to-come-but-new-zealand-may-be-better-prepared-than-other-countries-175819">The most challenging phase of the Omicron outbreak is yet to come, but New Zealand may be better prepared than other countries</a>
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<p>But childhood coverage of MMR was not high enough at the time (nor has it been historically), leaving a <a href="https://journal.nzma.org.nz/journal-articles/a-measles-epidemic-in-new-zealand-why-did-this-occur-and-how-can-we-prevent-it-occurring-again">known immunity gap</a> of susceptible teens and young adults. </p>
<p>Significant efforts have since been made to <a href="https://www.health.govt.nz/your-health/healthy-living/immunisation/measles-vaccination">close this gap</a> in MMR coverage, although these have been dwarfed by the COVID-19 vaccination campaign. </p>
<p>The upshot is a potential perfect storm for another measles outbreak, with low MMR coverage worldwide and locally. Measles could “walk” through New Zealand airports and meet under-immunised tamariki and rangatahi (youth). </p>
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<h2>Prevention as cure</h2>
<p>There is some good news, however. This year we’ve seen the introduction of new initiatives to help manage surges of winter ills, including the government funding influenza vaccines for children aged three to 12. </p>
<p>This is welcome, as influenza crosses our border every year (with the <a href="https://doi.org/10.1038/s41467-021-21157-9">exception of 2020</a> when COVID-19 public health measures, including quarantine and mask wearing, were in force). Because children are often <a href="https://www.influenza.org.nz/children/influenza-disease-vaccination-and-children">considered super-spreaders</a>, vaccination of children can reduce influenza-like illness and related costs in both tamariki and their whānau. </p>
<p>But the message from World Health Organization Director-General Tedros Adhanom Ghebreyesus remains urgent:</p>
<blockquote>
<p>Planning and tackling COVID-19 should also go hand-in-hand with vaccinating for killer diseases like measles, pneumonia and diarrhoea. </p>
</blockquote>
<p>In Aotearoa New Zealand, the COVID-19 vaccination experience has also shown how Māori and Pacific community health providers can help reach high vaccination targets – especially when combined with good outreach services, increasing vaccination providers beyond GP clinics, and building the vaccination workforce.</p>
<p>But right now the statistics paint a concerning picture. Low childhood immunisation coverage puts tamariki at risk of <em>many</em> preventable and serious diseases and adds a major burden to the <a href="https://theconversation.com/resurgent-covid-19-flu-and-other-viruses-are-pushing-new-zealands-health-system-to-the-limit-and-now-winter-is-coming-183536">already strained healthcare system</a>. </p>
<p>Prevention must be our top priority. It is better than the best cure, and will protect the health system from overload so it is available for those who need urgent care.</p><img src="https://counter.theconversation.com/content/188157/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anna Howe receives funding from the Health Research Council. While not the principal investigator she has been involved in research projects funded by GSK and was the first KPS Research Fellow. She works with the Immunisation Advisory Centre as their Research and Policy Analyst.</span></em></p><p class="fine-print"><em><span>Emma Best is as a member of anti-infectives Subcommittee of PHARMAC and holds research grants Health and Research Council. She works as a medical advisor for the Immunisation Advisory Centre </span></em></p><p class="fine-print"><em><span>Dr. Matthew Hobbs receives funding from the New Zealand Health Research Council, Cure Kids/A Better Start National Science Challenge and IStar. He was also previously funded as a researcher by the New Zealand Ministry of Health. </span></em></p>The risk of serious disease outbreaks among NZ children is now very real. Some childhood immunisation rates have dropped from about 80% in early 2020 to 67% by June 2022, and as low as 45% for Māori.Anna Howe, Research Fellow, University of Auckland, Waipapa Taumata RauEmma Best, Senior Lecturer, Department of Child and Youth Health, University of Auckland, Waipapa Taumata RauMatthew Hobbs, Senior Lecturer (Above the Bar) in Public Health and Co-Director of the GeoHealth Laboratory, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1443322020-08-12T12:00:59Z2020-08-12T12:00:59ZA COVID-19 vaccine needs the public’s trust – and it’s risky to cut corners on clinical trials, as Russia is<figure><img src="https://images.theconversation.com/files/352381/original/file-20200811-20-179mzzz.jpg?ixlib=rb-1.1.0&rect=187%2C22%2C743%2C551&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">On Aug. 11, Russian President Vladimir Putin announced that a coronavirus vaccine developed in the country has been registered for use.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/photo-shows-vials-of-vaccine-called-gamcovidvac-in-moscow-news-photo/1228002428?adppopup=true">Russian Health Ministry/Handout/Anadolu Agency via Getty Images</a></span></figcaption></figure><p>Russia’s announcement that a <a href="https://www.politico.com/news/2020/08/11/russia-coronavirus-vaccine-putin-daughter-393455">fast-tracked COVID-19 vaccine</a> is registered there, with plans for quick distribution in the general population this fall, is being <a href="https://www.nature.com/articles/d41586-020-02386-2">condemned by scientists worldwide</a>.</p>
<p>Findings from scientific studies of this vaccine, named “Sputnik V,” are not available. Large safety and efficacy trials <a href="https://sputnikvaccine.com/about-vaccine/clinical-trials/">are only now getting underway</a>. But despite only two months of preliminary testing in people, Russian President Vladimir Putin called the vaccine “<a href="https://www.bbc.com/news/world-europe-53735718">quite effective</a>” and it’s <a href="https://www.bloomberg.com/news/articles/2020-08-11/putin-says-russia-has-registered-world-s-first-covid-19-vaccine">received regulatory approval</a>.</p>
<p>In other places, notably the <a href="https://www.weforum.org/agenda/2020/06/vaccine-development-barriers-coronavirus/">United States, China and the European Union</a>, even as <a href="https://www.nationalgeographic.com/science/health-and-human-body/human-diseases/coronavirus-vaccine-tracker-how-they-work-latest-developments-cvd/">researchers rush to develop vaccines</a>, they continue to publish studies of these vaccines at a more measured pace than is happening in Russia.</p>
<p>As an <a href="https://scholar.google.com/citations?user=RNembkwAAAAJ&hl=en&oi=ao">epidemiologist who studies vaccine hesitancy and vaccine-preventable disease</a>, I’m concerned about this news from Russia. After essential workers and high-risk groups are vaccinated, I would want to be among the first in line for an approved COVID-19 vaccine, but the medical research system must make sure any vaccine is safe and effective before distributing it to the population at large.</p>
<h2>Clinical trials have a valuable role</h2>
<p>Before any drug, vaccine or medical device is licensed for use in the general population, it needs to go through <a href="https://www.historyofvaccines.org/content/articles/vaccine-development-testing-and-regulation">several rounds of large-scale testing</a>. These studies are designed to make sure the intervention is safe and effective, and to understand what the appropriate dosage will be.</p>
<p><iframe id="zGYqv" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/zGYqv/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Under normal conditions, the research required to bring a vaccine to market <a href="https://doi.org/10.1186/s12961-020-00571-3">can take decades</a>. For example, before the HPV vaccine was <a href="https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5920a4.htm">licensed in the U.S. in 2006</a>, a phase III clinical trial <a href="https://doi.org/10.1016/S0140-6736(09)61248-4">enrolled 18,644 participants in 2004-2005</a>, a phase II clinical trial had <a href="https://doi.org/10.1016/S0140-6736(04)17398-4">enrolled 1,113 participants in 2000</a>, and the laboratory studies that led to a vaccine candidate had been <a href="https://doi.org/10.2147/tcrm.2006.2.3.259">published in the early 1990s</a>.</p>
<p>In the face of the coronavirus pandemic, scientists around the globe are focusing their efforts on developing a COVID-19 vaccine. <a href="https://www.knowablemagazine.org/article/health-disease/2020/getting-covid-19-vaccine-quickly-and-safely">They’re working at an</a> <a href="https://theconversation.com/what-needs-to-go-right-to-get-a-coronavirus-vaccine-in-12-18-months-136816">unprecedented pace to move through the necessary clinical trials</a> to end up with a safe and effective vaccine. One of the most time-consuming parts of clinical trials is enrolling participants, and pharmaceutical companies have <a href="https://doi.org/10.1186/s12961-020-00571-3">sped up this process</a> by lining up volunteers early, obtaining important baseline data from them even before a vaccine candidate is available.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/l0ZBZ2Zy7Lw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Here’s how drugs are tested and approved in the U.S.</span></figcaption>
</figure>
<h2>Problems if the vaccine is released too early</h2>
<p>Carefully conducted clinical trials are necessary to identify any problems with the vaccine. For example, studies of a new type of measles vaccine in the early 1990s found that it was <a href="https://apps.who.int/iris/bitstream/handle/10665/228552/WER6748_357-361.PDF">detrimental to baby girls</a>, and so it was never licensed to the general population. The existing measles or measles-mumps-rubella vaccine available in the U.S. and other countries is <a href="https://www.cdc.gov/vaccinesafety/vaccines/mmr/mmr-studies.html">highly safe and effective</a>. </p>
<p>It could also be that the vaccine is not effective in some categories of people. Phase I and II clinical trials have small sample sizes and may not include individuals from high-risk groups. For example, a recently published phase II clinical trial of a COVID-19 vaccine <a href="https://doi.org/10.1016/S0140-6736(20)31605-6">excluded obese people, those with chronic diseases and pregnant women</a>. However, these are all groups that should be able to get the vaccine in the future. More studies, including phase III trials, are necessary to discover if the vaccine works in the general population. Preliminary results should be <a href="https://www.reuters.com/article/us-health-coronavirus-vaccines-explainer/when-will-a-coronavirus-vaccine-be-ready-idUSKCN2571H2">available by the end of 2020</a>.</p>
<p>The concern is that by introducing the vaccine early, without adequate testing of safety, effectiveness and dosing, the population may be presented with a vaccine which is not safe or not effective, and with little information on which vaccine schedule is best.</p>
<p>Food and Drug Administration Commissioner Dr. Stephen Hahn has said the FDA <a href="https://www.mercurynews.com/2020/08/10/commissioner-fda-wont-cut-corners-on-covid-19-vaccine/">will not “cut corners”</a> in approving a COVID-19 vaccine in the U.S. despite an accelerated program, <a href="https://abcnews.go.com/Politics/public-health-experts-scientists-confident-vaccine-process-criticism/story?id=72216320">dubbed Operation Warp Speed</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="archival photo of packing vials of polio vaccine into boxes" src="https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=492&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=492&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=492&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=619&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=619&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352382/original/file-20200811-14-292m13.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=619&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In 1956, boxes of polio vaccine were rushed for delivery, but only after clinical trials concluded and it was approved by the FDA.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/indianapolis-in-at-the-eli-lilly-and-company-plant-in-the-news-photo/514874700?adppopup=true">Bettmann via Getty Images</a></span>
</figcaption>
</figure>
<h2>Rushing to market</h2>
<p>But is there ever an ethical reason to release a vaccine early, even without going through all phases of clinical trials?</p>
<p>Although it would be wonderful to get a vaccine into the population quickly, there could be substantial downsides if researchers and manufacturers cut corners. Imagine a vaccine that often had serious side effects that weren’t caught in small trials before it was widely administered.</p>
<p>[<em>Research into coronavirus and other news from science</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-research">Subscribe to The Conversation’s new science newsletter</a>.]</p>
<p>An untested vaccine wouldn’t just harm the people vaccinated. If negative perceptions about the safety or efficacy of a COVID-19 vaccine spread throughout the population, it could limit how many people are willing to get the shot and perpetuate disease transmission.</p>
<p>Trust in vaccination programs is crucial. Russia, in fact, provides an important historical example. In the 1990s, trust in the country’s public health system rapidly decreased, and rates of diphtheria-tetanus-pertussis vaccination fell as a result. A large outbreak of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2640235/?tool=pmcentrez&report=abstract">diphtheria then spread through eastern Europe</a>, leaving over 4,000 people dead.</p>
<p>Hasty rollout of a COVID-19 vaccine could prime people not only to not trust the COVID-19 vaccine, but also to doubt vaccination and public health systems as a whole. </p>
<p>Vaccinations should be developed by impartial scientists and evaluated by nonpartisan government officials. By cutting red tape, procedures can be prioritized and sped up, but they must not be skipped.</p><img src="https://counter.theconversation.com/content/144332/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abram L. Wagner receives funding from the NIH and NSF. </span></em></p>As Russia fast tracks a coronavirus vaccine, scientists worry about skipped safety checks – and the potential fallout for trust in vaccines if something ends up going wrong.Abram L. Wagner, Research Assistant Professor of Epidemiology, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1259742019-12-04T15:17:51Z2019-12-04T15:17:51ZComplacency could delay the final push to eradicate polio<figure><img src="https://images.theconversation.com/files/303144/original/file-20191122-74603-tfic2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Nigerian child receives a dose of the polio vaccine</span> <span class="attribution"><span class="source">EPA</span></span></figcaption></figure><p>Great strides have been made in the global effort to eradicate polio. Reported cases of wild poliovirus have <a href="https://www.who.int/news-room/fact-sheets/detail/poliomyelitis">decreased by over 99%</a> from an estimated 350,000 cases in 1988 to 33 in 2018.</p>
<p>Polio is a <a href="https://www.who.int/news-room/fact-sheets/detail/poliomyelitis">highly infectious disease</a> caused by a virus that invades the nervous system, and can cause total paralysis in a matter of hours. It’s spread mainly through food and water that are contaminated with faecal matter. </p>
<p>The <a href="http://polioeradication.org/">goals</a> to eradicate polio by 2000, then 2018, were both missed. </p>
<p>There are three strains of wild poliovirus: type 1, type 2 and type 3. Wild polio virus type 2 was eradicated in 2015. Most recently, the World Health Organisation <a href="https://www.who.int/news-room/feature-stories/detail/two-out-of-three-wild-poliovirus-strains-eradicated">announced</a> that type 3 poliovirus had been eradicated. </p>
<p>The goal of ending all three types of the virus is within reach. Only two countries, Afghanistan and Pakistan, still have poliovirus circulating in the environment and causing disease in patients. </p>
<p>Today it’s easy to forget how common this disease once was and how it changed and ended lives. The danger in this is that complacency sets in and the strategies that were successful in fighting the disease – such as vaccination – are no longer followed. </p>
<p>This has happened with other diseases. For example, measles <a href="https://www.who.int/immunization/newsroom/measles-data-2019/en/">has begun to recur in several countries</a> even though it can be prevented through vaccination. </p>
<p>Steps are being taken to ensure that this doesn’t happen with polio. Global leaders recently pledged <a href="https://www.who.int/news-room/detail/19-11-2019-global-leaders-pledge-us-2.6-billion-to-eradicate-polio-at-the-reaching-the-last-mile-forum-in-abu-dhabi">US$2.6 billion</a> as part of the first phase of the funding needed to eradicate the disease by 2023. </p>
<p>But it will take more than money to contain and eradicate it. It also requires constant vigilance.</p>
<h2>Holding the line</h2>
<p>Poliomyelitis is a severe paralytic illness caused by the poliovirus, which causes symptoms in one out of 200 infected individuals. Hundreds of thousands of <a href="http://www.nicd.ac.za/media/videos/polio-documentary/">people survived</a> by spending long periods in an “iron lung”. It’s an invention many people today have never heard of – a ventilator that allowed patients to breathe with mechanical help when polio affected their muscles. Today, respirators replace the iron lung. </p>
<p>Polio was <a href="https://www.who.int/news-room/fact-sheets/detail/poliomyelitis">common</a> and has now become rare due to efficient control efforts. This has resulted in a decreased perception of the risks associated with the disease. </p>
<p>As the number of cases falls to near zero, the quantity of resources needed to eradicate it may appear disproportionate to the risk. But any breakdown in control efforts will undermine all achievements over the previous decades by leaving open the chance that a small number of cases becomes a large number again. This catastrophic scenario should be avoided.</p>
<p>Maintaining polio-free status and going further to eradicate polio still requires considerable efforts from countries and regions. </p>
<p>Reducing polio to zero new cases in several regions of the world took decades of a <a href="http://polioeradication.org/">global synchronised effort</a>. A similar global effort resulted in the <a href="https://www.livescience.com/65304-smallpox.html">eradication of smallpox</a> by 1979.</p>
<p>Because polio is highly contagious, a single case in one country can undo decades of progress. It can spread across a country as well as across regions where it had previously been eliminated. The most important intervention to stop this from happening is to ensure high vaccination coverage. </p>
<p>Countries can be in danger of losing their polio free status if they’re not vigilant. Take the case of South Africa as an example. The country was declared polio-free in 2006 but this was rescinded in 2017 as a result of challenges with several aspects of polio control. There were particular problems with surveillance and vaccination coverage. After these were addressed, South Africa regained its <a href="http://www.nicd.ac.za/south-africa-certified-polio-free/">polio-free status in 2019</a>. </p>
<h2>The way forward</h2>
<p>To achieve polio eradication, all countries must reinforce disease surveillance and strengthen their immunisation programmes. The vaccines used for polio control are safe and effective but no less than 95% of the population needs to be vaccinated.</p>
<p>The <a href="http://polioeradication.org/wp-content/uploads/2019/06/english-polio-endgame-strategy.pdf%E2%80%8B_http://polioeradication.org/_%E2%80%8B">Global Poliomyelitis Eradication Initiative</a> co-ordinates the polio endgame strategy and has outlined the steps that should lead to polio eradication and subsequently maintain a polio-free world. </p>
<p>Tremendous resources are required to execute this strategy. When a disease isn’t highly visible, it’s not always easy to convince stakeholders that the investment is worth it.</p>
<p>But, building on lessons learned from the elimination of types 2 and 3 polioviruses as well as the eradication of smallpox in the 1970s, the dream of achieving a polio-free world is possible.</p><img src="https://counter.theconversation.com/content/125974/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Suchard discloses having received funding, administered through her university, for speaker honoraria and consultancy work from Aspen GSK, Prepex Circ Med Tech ltd and Paediatric Management Group. She has administered conference funding sponsored by Sanofi Pasteur and been a sponsored delegate to Vaccinology congresses. As part of her responsibilities at the National Institute for Communicable Diseases, she engages regularly with the World Health Organisation and the National Department of heath regarding issues related to the Expanded Programme on Immunization and is a member of the National Advisory Group on Immunization..</span></em></p><p class="fine-print"><em><span>Villyen Motaze 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>Now is not the time to ease up the prevention effort, or decades of progress could be undone.Villyen Motaze, Epidemiologist and PhD Fellow, National Institute for Communicable DiseasesMelinda Suchard, Head, Centre for Vaccines and Immunology, National Institute for Communicable DiseasesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1278382019-12-03T16:19:59Z2019-12-03T16:19:59ZChildren and HIV: what we found about vaccine-preventable diseases<figure><img src="https://images.theconversation.com/files/304133/original/file-20191127-112484-2dhb4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">HIV-infected and exposed children are vulnerable to vaccine-preventable diseases.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Sub-Saharan African countries account for about a third of the <a href="https://www.who.int/immunization/monitoring_surveillance/burden/estimates/en/">global burden</a> of vaccine-preventable diseases. These diseases are responsible for a large proportion of deaths in children under the age of five. </p>
<p>But there is a knowledge gap about the burden of vaccine-preventable diseases among HIV-infected and HIV-exposed children (HIV-negative children born to women with HIV) in sub-Saharan Africa. It’s important to know more about this because of the extra vulnerability of children infected with – and exposed to – HIV. It’s also essential because health care interventions such as vaccination programmes need to be based on evidence. </p>
<p>We wanted to get a better understanding of the disease burden and to determine what kind of information is missing. We <a href="https://www.ncbi.nlm.nih.gov/pubmed/30945963">reviewed and analysed</a> scientific literature about how children in sub-Saharan Africa have been affected by vaccine-preventable diseases since the advent of HIV in the 1980s. </p>
<p>We wanted to find out how prevalent these diseases are among children who are infected by – or exposed to – HIV. We also wanted to know how many new infections are occurring each year and how many children are dying as a result. We looked for trends and the current burden of vaccine-preventable disease in the region.</p>
<p>The diseases we looked at are tuberculosis (TB), rotavirus gastroenteritis, diphtheria, pertussis, pneumococcal diseases, hepatitis B infection and measles. </p>
<h2>What we found</h2>
<p>This study shows that some vaccine-preventable diseases still have high incidence, prevalence and fatality rates in HIV-infected and HIV-exposed children.</p>
<p>We found that, across sub-Saharan African countries, new cases of TB have been decreasing by a rate of 12.5% per year from 2000 to 2010, and 1.5% per year between 2011 and 2018. But the number of new cases every year is still relatively high when compared to the <a href="https://www.who.int/tb/strategy/end-tb/en/">World Health Orgaisation’s</a> goals to end the disease. Despite the reduction in new TB cases among children in general, there are still hotspots such as Nigeria, South Africa and Cote d'Ivoire. </p>
<p>Sub-Saharan Africa had the highest hepatitis B virus burden among children and adolescents in the 1990s. Our study shows the burden has declined, primarily due to immunisation programmes. </p>
<p>But a <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=Hepatitis+B+virus+prevalence+and+vaccine+response+in+HIV-infected+children+and+adolescents+on+combination+antiretroviral+therapy+in+Kigali%2C+Rwanda">study</a> conducted in Rwanda still showed high prevalence of hepatitis B virus infection among HIV-infected and HIV-exposed children. Likewise, new cases and deaths due to <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60222-6/fulltext">diarrhoea and pneumonia</a> are much higher in low-income African countries than in the more developed western high-income countries.</p>
<p>We also found that TB was the most researched disease in HIV-infected and HIV-exposed children in Africa. This is because people with HIV are highly susceptible to TB.</p>
<p>Additionally, we found some gaps in the available knowledge. Many African countries haven’t done much research on diseases among HIV-infected and HIV-exposed children. Important vaccine-preventable diseases such as poliomyelitis, diphtheria, tetanus and yellow fever had no eligible studies that we could include in our review. </p>
<p>There were also geographical inequalities in the available research. South Africa contributed about half of the articles we included. Nigeria and Kenya followed with fewer studies.</p>
<p>It’s important to know the burden of different diseases so that health care workers and policymakers can allocate resources where they are needed most and get the best possible vaccination coverage. It’s especially important to know more about the disease burden and trends among HIV-infected and exposed children because their immune systems are compromised.</p>
<p>For example, the TB vaccine may <a href="https://www.who.int/immunization/policy/Immunization_routine_table1.pdf?ua=1">not be suitable</a> for children with poor immune systems, so more needs to be done about finding a suitable vaccine. These children may also need booster doses of vaccines for preventable diseases.</p>
<h2>The way forward:</h2>
<p>Governments and other supporting agencies should ensure that every child has access to routine childhood vaccines. </p>
<p>The research capacity of clinicians, researchers and health administrators in African countries should be built up so that they can conduct basic epidemiological research to inform their vaccination programmes. Health budgets should provide for research training. Researchers must share their findings with their immediate communities and health authorities and publish them in peer-reviewed journals.</p>
<p>Vaccination has proven to be the most <a href="https://www.sciencedirect.com/science/article/pii/B9781455700905000720?via%3Dihub">medically effective and cost-effective</a> intervention against certain diseases. But policymakers and health workers must have a good handle on vaccine-preventable diseases in their geographic areas to come up with effective interventions.</p>
<p>Countries should urgently introduce newer vaccines for illnesses such as rotavirus, Haemophilus influenzae type B and pneumococcal disease. </p>
<p>To ensure better vaccine uptake, it’s necessary to ensure that children are vaccinated when they get in touch with health care workers. Health care workers also need to address the myths, misconceptions and misinformation that cause community members to avoid vaccination.</p>
<p>Other <a href="https://www.who.int/maternal_child_adolescent/documents/global_action_plan_pneumonia_diarrhoea/en/">supportive interventions</a> such as provision of potable water and promotion of hygiene practices can also mitigate the effect of diseases in the vulnerable population.</p>
<p>Policymakers should work towards ensuring an equitable share of health care finance and resources. </p>
<p>All these activities will help in the control and prevention of vaccine-preventable diseases in sub-Saharan Africa.</p><img src="https://counter.theconversation.com/content/127838/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Olatunji Adetokunboh receives funding from National Research Foundation</span></em></p>Effective health care interventions are very important for sub-Saharan Africa because the region has a high burden of vaccine-preventable diseases.Olatunji Adetokunboh, National Public Health Liaison/Researcher, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1246602019-10-07T14:45:06Z2019-10-07T14:45:06ZOutbreaks of measles: compounding challenges in the DRC<figure><img src="https://images.theconversation.com/files/295441/original/file-20191003-52810-184ckhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many families in the DRC can't routinely access preventive services.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>An outbreak of measles that began in early 2019 in the southeast corner of the Democratic Republic of the Congo (DRC) has now spread to all 26 provinces. Over 180,000 cases and more than <a href="https://theconversation.com/over-3-000-killed-by-deadly-virus-in-democratic-republic-of-the-congo-this-year-and-its-not-ebola-123220">3,000 deaths</a> have been reported. The outbreak has disproportionately affected young children under five years of age. Similar outbreaks occurred previously in the DRC in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4105555/">2011</a> and again in <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)00115-4/fulltext">2015</a>. </p>
<p>This is the largest and most fatal of the <a href="https://www.cdc.gov/globalhealth/measles/globalmeaslesoutbreaks.htm">large measles outbreaks</a> across the world this year. These have occurred in the Ukraine, Philippines, Brazil, US, New Zealand, Madagascar and Nigeria. While the details of each individual outbreak vary, the root cause of measles outbreaks is always the same: too few children receive timely and effective vaccination.</p>
<p>The outbreak in the DRC highlights all of the various causes for episodic measles outbreaks. The delivery of measles vaccine in endemic areas must contend with a biological catch-22. From birth to about nine months of age, most infants have maternal antibodies that protect them from measles infection. But these antibodies also prevent the measles vaccine from conferring lifelong immunity. </p>
<p>Those children whose maternal immunity wears off early are at risk of infection at an age when measles infection can be most severe. Thus, health systems in endemic regions, like the DRC, employ a first dose at a relatively early age (nine months) to immunise these vulnerable children. Later they provide a second dose to catch those for whom the first dose didn’t provide protection.</p>
<p>The weak spot of this strategy is the accessibility of routine preventive health services. In the DRC, as in many underfunded health systems, many families cannot routinely access timely preventive services. This can be because they live too far from clinics, or because clinics are in bad shape. </p>
<p>To combat limited vaccination access, the DRC conducts periodic <a href="https://www.who.int/immunization/diseases/measles/en/">“supplemental vaccination activities”</a>. These are large, coordinated efforts to bring second dose opportunities into every community, vaccinating all children under five years of age, regardless of prior vaccination. The expense and logistics of these massive efforts means that they can only be conducted every few years. </p>
<p>The unfortunate consequence is that, in the years in between them, many children are born and not vaccinated. This sets the stage for large outbreaks.</p>
<h2>On the ground</h2>
<p>Many specific challenges in the DRC compound the already difficult task of vaccine delivery. </p>
<p>Years of <a href="https://theconversation.com/ebola-in-the-congo-a-forgotten-conflict-became-a-danger-to-world-health-122950">internal conflict</a> have displaced millions from their homes, limiting their access to preventive health services. The country has an <a href="http://worldpopulationreview.com/countries/dr-congo-population/">estimated population</a> of 87 million, of which more than half are children. About two thirds live in rural areas and <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202742">40%</a> of mothers report distance to health facilities as a challenge when getting health care.</p>
<p>In addition, inherent mistrust of government-run programmes prevents some from seeking care. Those who do are met by health-care workers who want to help, but are hampered by stock outages or unstable refrigeration necessary to store vaccines in the prescribed temperature range. Many are understaffed or simply don’t have sufficient vaccines available due to the fragility of cold-storage and supply chain in remote areas.</p>
<p>All of this combines to leave more than <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202742">40%</a> of children born in the DRC unvaccinated in any given year. This risk isn’t uniformly distributed. Some remote areas and areas of conflict have much <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456602/">lower coverage</a>. </p>
<p>Once an outbreak begins, rapid response to provide vaccination to children at risk is critical. This first requires detection and confirmation of the outbreak, and must be followed immediately by a <a href="https://www.unmultimedia.org/avlibrary/asset/2460/2460459/">massive effort to coordinate agencies</a>, and often NGO partners, to mount a response in affected or at risk areas. </p>
<p>Even when cases of measles are detected in clinics, limited diagnostic and communication infrastructure can cause significant lags in triggering the outbreak response. The DRC currently has only one reference laboratory that can run the blood tests necessary to confirm a measles outbreak. Transporting and processing samples can take weeks. Add to this the competing demands of a health system combating <a href="https://theconversation.com/ebola-returns-to-the-drc-for-the-10th-time-heres-what-we-know-101048">two Ebola outbreaks</a> in the past two years, and these lags can become larger.</p>
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Read more:
<a href="https://theconversation.com/how-the-drcs-ebola-crisis-has-led-to-children-dying-from-measles-119946">How the DRC's Ebola crisis has led to children dying from measles</a>
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<p>Coordination efforts for outbreak response have been improving in the DRC. The Ministry of Health has partnered with the Measles and Rubella Initiative, the World Health Organisation and Gavi, the vaccine alliance, to deploy <a href="https://measlesrubellainitiative.org/measles-news/the-minister-of-health-in-the-democratic-republic-of-congo-declares-a-measles-epidemic/">vaccination campaigns</a> in April 2019 and again in October 2019. The aim is to vaccinate more than 20 million children under the age of five nationwide against measles. </p>
<p>Medecins Sans Frontieres has additionally conducted several targeted <a href="https://www.msf.org/msf-launches-mass-measles-vaccination-campaign-country-ravaged-catastrophic-health-situation">vaccination campaigns</a>, in conjunction with the Ministry of Health, in acutely affected areas.</p>
<h2>Tackling intractable problems</h2>
<p>The solution to measles outbreaks is deceptively easy: vaccinate more children. This belies the challenges along the path to that solution. In the DRC, as in many low and middle income countries, periodic supplemental vaccination activities have borne too much of the weight of the control effort. </p>
<p>Supplemental vaccination activities as discrete events are convenient for external partners to fund and to evaluate afterwards, and thus have become a favoured tool of organisations that are beholden to donors seeking measurable results.</p>
<p>While the benefits of supplemental vaccination activities are clear (they have saved millions of lives), they don’t address the fundamental need to improve routine vaccination. Improving routine vaccination coverage requires a broad, systems-wide approach that includes supply chain, training and financing of health system staff, and community engagement to get at the root causes of non-vaccination.</p>
<p>In the DRC this requires tackling seemingly intractable problems. One is health access for people internally displaced by conflict. Another is deep mistrust of government institutions and solutions from the global north in areas that have experienced decades of both colonial and internal oppression. </p>
<p>Technological and infrastructure solutions can help to make gains in vaccination coverage. Solutions ranging from the very simple – packaging vaccines in pre-loaded syringes to prevent wastage in remote clinics that see children infrequently – to the aspirational – micro-patch technology to allow thermostable, needle-free vaccination – hold real promise but are years from implementation at scale.</p>
<p>Mundane solutions hold the potential to make meaningful gains in improving immunisation rates overall and increasing equity. These solutions include improving surveillance and response by building new regional reference laboratories to reduce the burden on the single national lab and shorten the time to confirm outbreaks. </p>
<p>Additionally, trying out strategies to increase routine vaccine delivery throughout the year, rather than relying on campaigns every three or four years; and reinforcing national surveillance to allow targeted, reactive enhancement of vaccination activities in locations that are underperforming can help to achieve the goal of equitable control of measles.</p><img src="https://counter.theconversation.com/content/124660/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Ferrari receives funding from Gavi, the Vaccine Alliance and the Bill and Melinda Gates Foundation and serves as an ad hoc advisor to the World Health Organization and Medecins Sans Frontieres.</span></em></p>Even when cases of measles are detected in clinics, limited diagnostic and communication infrastructure can delay the response.Matthew Ferrari, Associate Professor of Biology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/570882016-04-05T12:30:32Z2016-04-05T12:30:32ZWhat’s behind Angola’s first yellow fever outbreak in three decades<figure><img src="https://images.theconversation.com/files/117456/original/image-20160405-13564-1kmjc6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An Angolan soldier administers a yellow fever vaccine to a child at "Quilometro 30" market, Luanda.</span> <span class="attribution"><span class="source">EPA/Joost de Raeymaeker</span></span></figcaption></figure><p><em>The World Health Organisation has declared the yellow fever outbreak in Angola a <a href="http://www.who.int/hac/donorinfo/g3_contributions/en/">grade 2 emergency</a>.
This means that it can have moderate public health consequences. This requires an emergency support team run from the organisation’s regional office providing support. Health and medicine editor Candice Bailey spoke to Jacqueline Weyer, a senior medical scientist from the National Institute for Communicable Diseases in South Africa, to understand the latest outbreak.</em></p>
<p><strong>How serious is the outbreak in Angola? When last did this happen?</strong></p>
<p>The <a href="http://www.who.int/csr/don/22-march-2016-yellow-fever-angola/en/">outbreak</a> started in December 2015 in the country’s capital, Luanda. The province is most affected and has had 281 confirmed cases and 129 deaths.</p>
<p>There are also suspected cases being reported in 16 of the 18 provinces in the country. To date, nearly 1,500 suspected and confirmed cases have been reported, with nearly 200 deaths. This marks the largest yellow fever outbreak in years.</p>
<p>The last time Angola had a yellow fever outbreak was in the 1980s. The county is considered endemic for yellow fever, which means it is known to occur there naturally and cases could be expected at any time. The outbreak culminates from a confluence of factors – including under-vaccination of the at-risk population but also climatic conditions that support the proliferation of the mosquito vector of the virus.</p>
<p><strong>Is Africa a yellow fever hot spot? Why are countries like Angola at higher risk?</strong></p>
<p>Yellow fever outbreaks are reported almost annually in risk countries but in most cases the number of cases are typically not considerable.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=534&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=534&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117195/original/image-20160403-6780-fhb1fm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=534&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">African countries at high risk of yellow fever outbreaks.</span>
<span class="attribution"><a class="source" href="http://www.cdc.gov/yellowfever/maps/index.html">Centers for Disease Control</a></span>
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<p>A total of 44 countries located in the central belt of Africa and in north and central South America are considered endemic for <a href="http://www.cdc.gov/yellowfever/maps/index.html">yellow fever</a>. In Africa, an estimated 508 million people live in 31 countries at risk. </p>
<p>The virus is present in tropical and subtropical areas. It circulates naturally among some primates and certain types of mosquitoes. In African countries different types of <a href="http://entnemdept.ufl.edu/creatures/aquatic/aedes_aegypti.htm"><em>Aedes</em> mosquitoes</a> carry the disease. The <a href="http://www.who.int/denguecontrol/mosquito/en/"><em>Aedes aegypti</em> mosquito</a> is the most important vector of the virus to humans in urban settings. It is typically active during the day. In South American countries mostly <em>Haemagogus</em> mosquitoes are responsible. </p>
<p>When there are conditions such as heavy rainfall in an area, the proliferation of mosquitoes can lead to an increase in the number of human cases, which consequently results in an outbreak.</p>
<p><strong>What is yellow fever and how do you know you have it?</strong></p>
<p>Yellow fever is a vaccine-preventable viral disease transmitted by certain types of mosquitoes.</p>
<p>If you were bitten by an infected mosquito it may take three to six days to develop any signs of disease. In many cases people might not even know that they are sick – they tolerate the infection well and recover quickly without support. In some cases, the outcomes may be more severe. This is often seen in older people. </p>
<p>If you become sick with yellow fever you may experience fever and general flu-like symptoms such as tiredness and body aches in the joints. People sometimes also complain of nausea, loss of appetite, vomiting and dizziness. </p>
<p>In some cases the infection will have a more serious effect on the body’s organs. This can be fatal. For example, the liver may be severely affected and the person may become jaundiced or yellow in colour. This is where the disease gets its name from. Some people may also start bleeding. This includes blood in their stools or urine, or oozing from needle puncture sites.</p>
<p><strong>How do you get it?</strong></p>
<p>You can only get infected with the virus if you have travelled to a country where the disease occurs and if you have not been vaccinated.</p>
<p>The virus is transmitted to humans primarily through mosquito bites. </p>
<p>You are likely to get yellow fever only if: </p>
<ul>
<li><p>you haven’t been vaccinated;</p></li>
<li><p>you are in a country in which the disease is endemic; and</p></li>
<li><p>you have been bitten by a mosquito infected with yellow fever.</p></li>
</ul>
<p>Human-to-human transmission of the virus is rare and is usually only associated with transmission in a hospital setting. In most of these instances health-care workers come into contact with contaminated equipment or other materials.</p>
<p><strong>Is there a cure?</strong></p>
<p>As with most viral diseases, there is no cure for yellow fever. Treatment is supportive. This means that the doctor will treat your symptoms. </p>
<p>Yellow fever can be prevented by vaccination. A yellow fever vaccine is required before travelling to a region that is endemic. You should get the vaccination at least ten days before travelling so that your body has time to respond and produce protective antibodies.</p>
<p>The vaccine is effective, safe to use, fairly cheap and provides lifelong immunity. People who have compromised immune systems may be precluded from vaccination and will be discouraged from travelling to risk areas. These include people living with HIV/AIDS, those on immunosuppressive drugs, infants under nine months old and pregnant women. People travelling to a yellow fever endemic area should consult their closest travel clinic for more information. </p>
<p><strong>Where are the big loopholes in tackling the spread of yellow fever?</strong></p>
<p>The biggest risk for outbreaks of yellow fever is rapid urbanisation.</p>
<p>Although there are ongoing initiatives to provide population-wide yellow fever vaccinations in risk areas, the rapid increase in the population in some cities makes this a challenging goal. </p>
<p>In Angola, mass vaccination campaigns have been conducted to bring the outbreak under control and prevent further cases. To stop the outbreak, the country developed a national response plan at the beginning of 2016 targeting more than 6.4 million people for yellow fever vaccination in Luanda alone. About 87% of people in the city have been vaccinated so far.</p>
<p>But the World Health Organisation has also flagged the <a href="http://www.who.int/csr/don/22-march-2016-yellow-fever-angola/en/">risk</a> of the disease spreading across borders and internationally. </p>
<p>A travel ban has not been placed on Angola, but if you’re travelling to the country – and other endemic regions such as Asia and Latin America – you must have yellow fever vaccination certificate.</p><img src="https://counter.theconversation.com/content/57088/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacqueline Weyer 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>Angola’s yellow fever outbreak has been declared a grade 2 emergency by the World Health Organisation.Jacqueline Weyer, Senior Medical Scientist, National Institute for Communicable Diseases, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.