tag:theconversation.com,2011:/us/topics/malaria-vaccine-7479/articles
Malaria vaccine – The Conversation
2023-10-23T14:05:32Z
tag:theconversation.com,2011:article/215717
2023-10-23T14:05:32Z
2023-10-23T14:05:32Z
Breakthroughs in medicine: top virologist on the two most important developments for Africa
<p><em>There have been several important breakthroughs in medical science recently. Crispr, mRNA, next-generation cancer treatments and game-changing vaccines are some of them. Oyewale Tomori, a virologist with decades-long involvement in managing diseases in Nigeria, gives his verdict on the most significant discoveries and what they mean for Africa.</em></p>
<h2>Are these extraordinary times for discoveries in medicine?</h2>
<p>Yes indeed, the world is living through extraordinary times, but not every part of the world has the luxury of these groundbreaking discoveries in medicine. Time stands extraordinarily still for some people in the world, in terms of the application and translation of the accelerated discoveries for medicine. </p>
<h2>Which two do you find the most exciting?</h2>
<p>The two I find most exciting, among so many other discoveries, are the new <a href="https://www.genome.gov/genetics-glossary/messenger-rna">mRNA</a> vaccine technology and the two malaria vaccines. </p>
<p>The advancements made in the generation, purification and cellular delivery of RNA have enabled the development of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9016686/#:%7E:text=RNA%20therapy%20is%20a%20term,activity%20of%20its%20target%20molecules.">RNA therapies</a> across a broad array of applications. For example RNA therapy destroys tumour cells in cancer. </p>
<p><a href="https://ysph.yale.edu/news-article/the-application-and-future-potential-of-mrna-vaccines/">Messenger RNA (mRNA)</a>, as the name suggests, is a messenger protein molecule that has the ability to deliver a specific set of instructions to the cells of the body to make pieces of protein. Once the protein particles are made, they show up on the cell’s surface. The presence of the protein alerts your immune system to mount a defence and create antibodies to fight off what it thinks is a possible infection. The body learns to recognise the viral protein as an enemy.</p>
<p>For example, when the <a href="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-vaccines">COVID-19 vaccine</a> is injected into the body, the cells are instructed to generate the spike protein that is normally found on the surface of <a href="https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html">SARS-CoV-2</a>, the virus that causes COVID-19. The protein that the body makes in response to the vaccine causes an immune response without a person ever having been exposed to the virus that causes COVID-19. </p>
<p>Later, if the person is exposed to the virus, the immune system will recognise the virus and respond to it. The <a href="https://ysph.yale.edu/news-article/the-application-and-future-potential-of-mrna-vaccines/">mRNA vaccines</a> are safe and they neither alter the DNA nor cause COVID-19 infection. </p>
<p>Previous research laid the groundwork for the technology, which resulted in the development, production, approval and deployment of an effective COVID-19 vaccine in less than a year. The <a href="https://www.nobelprize.org/prizes/medicine/2023/press-release/">2023 Nobel Prize in Medicine</a> was awarded to two scientists for “groundbreaking findings” on mRNA COVID-19 vaccines. </p>
<p>Since 2019, when COVID-19 was first reported, the disease has caused over <a href="https://covid19.who.int/">700 million cases and about 7 million deaths</a> globally. The technology is cost-effective and relatively simple to manufacture and can be <a href="https://pubmed.ncbi.nlm.nih.gov/30803823/">applied to the production of other vaccines</a>, especially for the neglected diseases that are common in Africa. mRNA is a transformative technology for vaccine development to control infectious diseases.</p>
<p>The approval of two malaria vaccines, the <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">RTS vaccine</a> in 2021 and the <a href="https://www.who.int/news/item/02-10-2023-who-recommends-r21-matrix-m-vaccine-for-malaria-prevention-in-updated-advice-on-immunization">R21 vaccine</a> this year, though not <a href="https://www.medicalnewstoday.com/articles/how-did-we-develop-a-covid-19-vaccine-so-quickly">accelerated discoveries</a> such as vaccines for COVID-19, are a huge step in the right direction. This is particularly exciting for malaria endemic areas of the world. Malaria causes more than <a href="https://www.nature.com/articles/d41586-023-03173-5">600,000 deaths</a> annually, the majority in children under five and pregnant women in Africa.</p>
<p>Although the malaria vaccines are no <a href="https://theconversation.com/new-malaria-vaccine-no-silver-bullet-but-an-important-step-towards-eradication-215052">silver bullets</a>, they are steps towards malaria eradication in Africa.</p>
<h2>What do these breakthroughs mean for Africa?</h2>
<p>The mRNA technology will serve as a template for the development of vaccines against long-standing diseases that are endemic in Africa, <a href="https://www.cdc.gov/vhf/lassa/index.html#:%7E:text=Fran%C3%A7ais%20(French),vector%20lives%20throughout%20the%20region.">Lassa fever</a> and other <a href="https://www.google.com/search?q=viral+hemorrhagic+diseases&rlz=1C1GCEA_enZA1069ZA1069&oq=viral+hemorrhagic+diseases&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTExMjZqMGoxNagCALACAA&sourceid=chrome&ie=UTF-8">viral hemorrhagic diseases</a>, as well as <a href="https://www.google.com/search?q=cholera&rlz=1C1GCEA_enZA1069ZA1069&oq=cholera&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIJCAEQABhDGIoFMgkIAhAAGEMYigUyDwgDEAAYQxiDARixAxiKBTIPCAQQABhDGIMBGLEDGIoFMgkIBRAAGEMYigUyDwgGEAAYQxiDARixAxiKBTIHCAcQABiABDIHCAgQABiABDINCAkQABiDARixAxiABNIBCTI1ODhqMGoxNagCALACAA&sourceid=chrome&ie=UTF-8">cholera</a>, <a href="https://www.cdc.gov/meningitis/index.html">meningitis</a> and others. </p>
<h2>What do African countries need to do to ride the wave of breakthroughs?</h2>
<p>Africa’s <a href="https://www.universityworldnews.com/post.php?story=20211124153120458">vulnerability</a> to lack of access to vaccines was clearly exposed during the COVID-19 pandemic. This calls for greater vaccine-manufacturing capacity and capabilities across the African continent. </p>
<p>Yet, despite numerous declarations in support of vaccine manufacturing in Africa, the <a href="https://cms.wellcome.org/sites/default/files/2023-01/Wellcome-Biovac-BCG-Scaling-up-African-vaccine-manufacturing-capacity-report-2023_0.pdf">African vaccine-manufacturing industry</a> is still nascent, with little progress made. The continent is manufacturing less than 1% of its required vaccine doses.</p>
<p>African countries must realise that investment in science, research and technology will produce significant returns.</p>
<p>Funding science and technology is a good economic bet. A recent <a href="https://sciencebusiness.net/why-fund-research">Science|Business report</a> suggests the long-term payback is in the order of 20% a year.</p>
<p>Africa’s poor public funding for research is well documented. In 2006, member countries of the African Union committed to spending 1% of their GDP on research and development. But by 2019, the continent’s funding was only <a href="https://www.nature.com/articles/d44148-022-00134-4">0.42%</a>, in sharp contrast to the global average of 1.7%. </p>
<p>Africa has about <a href="https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates">25%</a> of the global burden of unrelenting endemic communicable diseases and a rapidly escalating incidence of non-communicable diseases. </p>
<p>Efforts should be channelled to find solutions to <a href="https://www.who.int/news-room/fact-sheets/detail/hiv-aids#:%7E:text=Overview,cells%2C%20weakening%20the%20immune%20system.">AIDS</a>, <a href="https://www.mayoclinic.org/diseases-conditions/malaria/symptoms-causes/syc-20351184">malaria</a>, <a href="https://www.google.com/search?q=tuberculosis&rlz=1C1GCEA_enZA1069ZA1069&oq=tuberculosis&gs_lcrp=EgZjaHJvbWUyDwgAEEUYORiDARixAxiABDINCAEQABiDARixAxiABDINCAIQABiDARixAxiABDIHCAMQABiABDINCAQQABiDARixAxiABDINCAUQABiDARixAxiABDIHCAYQABiABDIHCAcQABiABDIHCAgQABiABDINCAkQABiDARixAxiABNIBCTMxMDRqMGoxNagCALACAA&sourceid=chrome&ie=UTF-8">tuberculosis</a> and other neglected diseases including <a href="https://www.cdc.gov/vhf/ebola/about.html#:%7E:text=Ebola%20disease%20is%20the%20term,primarily%20on%20the%20African%20continent.">Ebola</a>, <a href="https://www.cdc.gov/vhf/lassa/index.html#:%7E:text=Fran%C3%A7ais%20(French),vector%20lives%20throughout%20the%20region.">Lassa fever</a> and <a href="https://www.cdc.gov/poxvirus/mpox/index.html">mpox</a>. </p>
<p>African countries must reduce their dependence on donor funding for local research, but also stop pleading for the crumbs of equity for their health security, social well-being and orderly economic development.</p><img src="https://counter.theconversation.com/content/215717/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Oyewale Tomori 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>
This is an era of exciting advances in medical science. But Africa is in danger of being at the back of the queue once again. What should we be doing to make sure this doesn’t happen?
Oyewale Tomori, Fellow, Nigerian Academy of Science
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/214885
2023-10-03T14:19:16Z
2023-10-03T14:19:16Z
The long road to a new malaria vaccine, told by the scientists behind the breakthrough – podcast
<figure><img src="https://images.theconversation.com/files/551732/original/file-20231003-17-vu9c9t.jpg?ixlib=rb-1.1.0&rect=22%2C164%2C2807%2C1773&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-mosquito-sucking-blood-1430203604">Darkdiamond67 via Shutterstock</a></span></figcaption></figure><p>The world has waited decades for a malaria vaccine, and now two have come along in quick succession. On October 2, the World Health Organization (WHO) recommended that a new malaria vaccine, R21, developed by the University of Oxford be <a href="https://www.who.int/news/item/02-10-2023-who-recommends-r21-matrix-m-vaccine-for-malaria-prevention-in-updated-advice-on-immunization">rolled out for the prevention of malaria in children</a>, just two years after another vaccine, the RTS,S, got its endorsement. </p>
<p>In this episode of <em><a href="https://theconversation.com/uk/topics/the-conversation-weekly-98901">The Conversation Weekly</a></em> podcast, we find out why it’s been so hard to find a malaria vaccine – and hear from the scientists behind the new breakthrough.</p>
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<p>In 2021, <a href="https://www.who.int/teams/global-malaria-programme/reports/world-malaria-report-2022">619,000 people died from malaria</a>, the majority of them children. The search for a vaccine has been underway for decades, but it’s particularly difficult due to the complexity of the malaria parasite. </p>
<p>“It begins with a mosquito bite,” says Faith Osier, co-director of the Institute of Infection at Imperial College London. “It injects what we call sporozoite, a stage of the malaria parasite, that gets carried in your circulation into the liver and then it develops there”. About two weeks later, the parasites appear in the blood, morphing into different structures that are difficult to target with a vaccine. </p>
<p>But recent years have seen big breakthroughs in understanding what works. The RTS,S vaccine, which was developed by GSK, has been given to <a href="https://www.who.int/news/item/05-07-2023-18-million-doses-of-first-ever-malaria-vaccine-allocated-to-12-african-countries-for-2023-2025--gavi--who-and-unicef">1.7 million children in Ghana, Kenya and Malawi</a> since 2019. </p>
<p>In early October 2023, the WHO recommended the use of a second malaria vaccine, created by the University of Oxford, called R21, following the publication of <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4584076">results from phase III clinical trials</a> on children in Africa in a pre-print in The Lancet medical journal. </p>
<p>“We’re seeing about 75% efficacy of our vaccine,” says Adrian Hill, director of the Jenner Institute at the University of Oxford, which developed the new R21 vaccine. This means the vaccine can diminish “the number of clinical episodes that a child in Africa would get by 75%, compared to children who have not been vaccinated”. </p>
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Read more:
<a href="https://theconversation.com/we-could-eradicate-malaria-by-2040-says-expert-after-revolutionary-vaccine-is-approved-by-who-214798">'We could eradicate malaria by 2040' says expert after revolutionary vaccine is approved by WHO</a>
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<p>Alassane Dicko, a professor at the Malaria Research and Training Center at the University of Bamako in Mali, conducted one of the stages of the phase III trial. He told The Conversation Weekly that in some of the most vulnerable groups in their trial, babies between five and 17 months, “the efficacy was 80%” after 12 months. </p>
<p>For comparison, the <a href="https://microbiologycommunity.nature.com/posts/a-review-of-the-rts-s-malaria-vaccine-efficacy-impact-and-mechanisms-of-protection">RTS,S</a> vaccine showed around 55% efficacy after 12 months. </p>
<p>“It’s great to get higher efficacy, of course, but the big difference here with this vaccine is how you can manufacture it at a scale that is really needed to protect most of the children who need a malaria vaccine in Africa,” says Hill. </p>
<p>Oxford has been working with a partner, the Serum Institute of India, who it says has already established production capacity for 100 million doses a year. The higher volumes should also keep the cost of each dose relatively low. </p>
<p>To find out more about the vaccine, and what it means about the potential to fully eradicate malaria, listen to the full episode on <a href="https://podfollow.com/the-conversation-weekly/view">The Conversation Weekly</a> podcast. </p>
<p>A transcript of this <a href="https://cdn.theconversation.com/static_files/files/2997/Malaria_Vaccine_Transcript.pdf?1704360326">episode is now available</a>. </p>
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<p><em>This episode was written and produced by Katie Flood, with assistance from Gemma Ware and Mend Mariwany. Eloise Stevens does our sound design, and our theme music is by Neeta Sarl.</em></p>
<p><em>You can find us on Twitter <a href="https://twitter.com/TC_Audio">@TC_Audio</a>, on Instagram at <a href="https://www.instagram.com/theconversationdotcom/">theconversationdotcom</a> or <a href="mailto:podcast@theconversation.com">via email</a>. You can also subscribe to The Conversation’s <a href="https://theconversation.com/newsletter">free daily email here</a>.</em></p>
<p><em>Listen to <em>The Conversation Weekly</em> via any of the apps listed above, download it directly via our <a href="https://feeds.acast.com/public/shows/60087127b9687759d637bade">RSS feed</a> or find out <a href="https://theconversation.com/how-to-listen-to-the-conversations-podcasts-154131">how else to listen here</a>.</em></p><img src="https://counter.theconversation.com/content/214885/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adrian Hill receives funding from government and charitable funders of malaria vaccine development. He may benefit for a share of any royalty stream to Oxford University from the R21/MM vaccine. Alassane Dicko received grants from the Serum Institute of India, the Medical Research Council, the National Institute of Allergy and Infectious Diseases and Grand Challenges to conduct research on malaria vaccines. </span></em></p><p class="fine-print"><em><span>Faith Osier 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>
In this episode of The Conversation Weekly, we hear from the scientists behind a new malaria vaccine developed by the University of Oxford.
Daniel Merino, Associate Science Editor & Co-Host of The Conversation Weekly Podcast, The Conversation
Nehal El-Hadi, Science + Technology Editor & Co-Host of The Conversation Weekly Podcast, The Conversation
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/208726
2023-06-30T12:40:44Z
2023-06-30T12:40:44Z
Locally transmitted malaria in the US could be a harbinger of rising disease risk in a warming climate – 5 questions answered
<figure><img src="https://images.theconversation.com/files/534730/original/file-20230629-15-k04fb9.jpg?ixlib=rb-1.1.0&rect=8%2C17%2C5879%2C3910&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some evidence suggests that malaria mosquitoes are becoming resistant to insecticides.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/anopheles-maculipennis-royalty-free-image/522212584?phrase=malaria&adppopup=true">Paul Starosta/Stone via Getty Images</a></span></figcaption></figure><p><em>The Centers for Disease Control and Prevention reported on June 26, 2023, that five cases of <a href="https://emergency.cdc.gov/han/2023/han00494.asp">locally transmitted malaria had been identified</a> – four in Florida and one in Texas – since May 2023. These are the first cases of locally acquired mosquito-borne malaria in the U.S. since 2003.</em> </p>
<p><em>The Conversation spoke with <a href="https://stempel.fiu.edu/faculty-staff/profiles/chowdhury-rajiv.html">Dr. Rajiv Chowdhury</a>, a <a href="https://scholar.google.co.uk/citations?user=lmhOm1sAAAAJ&hl=en">global health expert</a> from Florida International University, about the significance of these cases and why they’re appearing now.</em></p>
<h2>1. What is malaria and how did these people become infected?</h2>
<p>Malaria is a serious and sometimes life-threatening disease caused by the bite of a female mosquito from the genus <em>Anopheles</em>, the vector <a href="https://www.niaid.nih.gov/diseases-conditions/malaria-parasite#">that transmits malaria</a>. </p>
<p>The most common symptoms are fever, chills, headaches, muscle aches and fatigue. These symptoms typically occur from 10 to 15 days after people are infected with the parasite. However, if untreated, more <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">severe symptoms</a> may appear that include impaired consciousness, difficulty breathing, convulsions, abnormal bleeding and more, which can ultimately lead to death.</p>
<p>The five cases in Florida and Texas were caused by the <em>Plasmodium vivax</em> parasite, which is the most common malaria-causing parasite strain <a href="https://www.ncbi.nlm.nih.gov/books/NBK538333/">outside of the African continent</a>. All are believed to be locally acquired, which means they were not connected to any international travel. In addition, there is no evidence to suggest that the cases in the two states are related. <em>Plasmodium vivax</em> is the most globally widespread of all <em>Plasmodium</em> strains and can cause severe, often fatal, infections. </p>
<p>All five patients have <a href="https://www.floridahealth.gov/newsroom/2023/06/20230626-mosquito-borne-illnesses.pr.html">reportedly recovered</a>, and surveillance for additional cases is ongoing.</p>
<h2>2. Why might these cases be surfacing now?</h2>
<p>There could be several factors driving the emergence of locally acquired malaria.</p>
<p>For one, climate change is <a href="https://doi.org/10.1016/S0140-6736(17)31119-4">causing a shift in weather patterns</a>, some of which can worsen malaria conditions. A higher average surface temperature from global warming could lead to higher mosquito migration in areas that were <a href="https://doi.org/10.1016/S2542-5196(22)00039-0">previously uninhabitable by <em>Anopheles</em> mosquitoes</a>.</p>
<p>These higher temperatures could also <a href="https://www.un.org/en/chronicle/article/climate-change-and-malaria-complex-relationship">enhance the growth rate and transmissibility of the parasites</a> responsible for malaria. These include Plasmodium parasite variants such as <em>vivax</em>, <em>knowlesi</em> and <em>falciparum</em>.</p>
<p>The effects of climate change can also lead to <a href="https://doi.org/10.1186/s12936-021-03718-x">higher rainfall and sea level rise</a> in many places – both of which can result in more areas or open spaces with stagnant water that typically serve as effective breeding grounds for mosquitoes. </p>
<p>Given these changes in local conditions, more cases could occur in populations that were previously <a href="https://doi.org/10.1073/pnas.1302089111">“immunologically naïve” to malaria</a>. In other words, since these people have never been exposed to it, their immune systems are ill-equipped to fight it.</p>
<p>Furthermore, when people travel to countries or areas where climate-driven malaria cases are on the rise, there is a greater possibility of bringing those infections back to the U.S., where local mosquitoes could be exposed to the parasite in an infected person’s blood. </p>
<p>Lastly, due to misuse and overuse of common antimalarial medications, <a href="https://doi.org/10.1016/S2666-5247(21)00249-4">such as artemisinin</a>, antimicrobial resistance has become <a href="https://www.cdc.gov/malaria/malaria_worldwide/reduction/drug_resistance.html">a major problem in many regions</a> of the world. This drives up the number of drug-resistant cases, the severity of the illness and the possibility of larger outbreaks.</p>
<p>This is further complicated by emerging <a href="https://www.who.int/teams/global-malaria-programme/reports/world-malaria-report-2022">resistance to insecticides</a> among <em>Anopheles</em> mosquitoes.</p>
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<figcaption><span class="caption">When traveling overseas this summer, here’s what to remember.</span></figcaption>
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<h2>3. How can people help prevent malaria transmission?</h2>
<p>The CDC and the Florida Department of Health are urging people to protect themselves by using bug spray, avoiding areas where mosquitoes congregate and covering exposed skin.</p>
<p>Precautions also include what’s known as “<a href="https://www.floridahealth.gov/newsroom/2023/06/20230626-mosquito-borne-illnesses.pr.html">drain and cover</a>” – in other words, draining standing water to prevent mosquitoes from multiplying and using screens to prevent mosquitoes from entering through doors and windows. Health departments also note that it’s important to drain or discard containers that can collect rainwater, such as flower pots, old tires and buckets. </p>
<h2>4. What are the available malaria treatments?</h2>
<p>There are several medicines used to prevent and treat malaria. The choice of medication typically depends on the type of malaria, whether a malaria parasite is resistant to a medicine, the weight or age of the person infected with malaria and whether the person is pregnant. </p>
<p>Most malaria medicines are taken in pill form. The most common include combination therapy medicines that include a class of <a href="https://doi.org/10.1016%2Fj.tips.2008.07.004">semi-synthetic drugs called artemisinins</a>. These kill malaria parasites by damaging their proteins and are usually the most effective treatment against malaria. <a href="https://medlineplus.gov/druginfo/meds/a682318.html#">Chloroquine phosphate</a>, a medicine that has been used for decades to prevent and treat malaria, is now recommended for treatment of infection with <em>Plasmodium vivax</em>, but only in places where the parasite is still sensitive to this medicine. Lastly, there’s <a href="https://medlineplus.gov/druginfo/meds/a607037.html#">primaquine</a>, a class of antimalarial drugs typically added to complement another treatment to prevent any relapse of infection. </p>
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<figcaption><span class="caption">With early diagnosis, malaria is very treatable.</span></figcaption>
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<h2>5. Are vaccines against malaria available?</h2>
<p>Nearly half of the <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">global population is currently at risk</a> of malaria, with almost 250 million cases and 620,000 deaths worldwide, mostly affecting children. Therefore, in October 2021, the World Health Organization began <a href="https://theconversation.com/who-approved-a-malaria-vaccine-for-children-a-global-health-expert-explains-why-that-is-a-big-deal-169501">recommending the widespread use</a> of a malaria vaccine known as RTS,S/ASOI for children who live in moderate- to high-risk areas.</p>
<p>This is the first-ever <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">vaccine for a human parasitic infection</a>. Trials show that the vaccine can <a href="https://doi.org/10.1016/S0140-6736(15)60721-8">significantly reduce malaria</a>, including severe malaria, among young children. </p>
<p>A group of scientists from the U.K. reported a <a href="https://doi.org/10.1016/S1473-3099(22)00442-X">modified version of this vaccine</a>, called R21, in September 2022. The early-phase clinical trial reported that the new vaccine is 80% effective at preventing disease in young children. However, real-world trials for this new candidate vaccine are still ongoing. </p>
<p>Other <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/biontech-initiates-clinical-trial-mrna-based-malaria-vaccine-candidate-2022-12-23/#">vaccine candidates</a> are currently being developed by BioNTech, the company behind the Pfizer/BioNTech mRNA COVID-19 vaccine, and through <a href="https://www.forbes.com/sites/roberthart/2023/06/05/novavax-partners-with-gates-foundation-offshoot-in-efforts-to-develop-malaria-and-tb-shots/?sh=2354fd313d51">joint efforts</a> between Novavax and the Bill & Melinda Gates Medical Research Institute.</p>
<p>While new malaria vaccines will be a major boost for curbing malaria worldwide, it will be critical for health departments to continue emphasizing other preventive strategies, especially in newly affected areas like Florida and Texas.</p><img src="https://counter.theconversation.com/content/208726/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rajiv Chowdhury 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>
After recent cases in Florida and Texas, authorities are advising the public to drain standing water sources to keep mosquitoes from multiplying.
Rajiv Chowdhury, Professor of Global Health, Florida International University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/204148
2023-04-24T12:04:29Z
2023-04-24T12:04:29Z
Nigeria has Africa’s highest malaria death rate - progress is being made, but it’s not enough
<figure><img src="https://images.theconversation.com/files/522576/original/file-20230424-1209-sj0dw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lagos residents use art to draw attention to the gaps in the prevention and treatment of malaria. According to UNICEF, over 1,000 children under the age of 5 catch malaria every day. </span> <span class="attribution"><span class="source">Pius Utomi Ekpei/AFP via Getty Images</span></span></figcaption></figure><p><em><a href="https://www.who.int/news-room/fact-sheets/detail/malaria">Malaria</a> is a major public health problem and can be life-threatening. The disease, mostly found in tropical countries, is transmitted to humans by the female Anopheles mosquito. Nearly half of the world’s population is at risk of the disease. <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">In 2021</a>, for instance, around 247 million cases of malaria were reported and <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">about 619,000</a> people died. <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">Four African countries</a> accounted for just over half of all malaria deaths worldwide: Nigeria (31.3%), the Democratic Republic of the Congo (12.6%), Tanzania (4.1%) and Niger (3.9%).</em></p>
<p><em><a href="https://msh.org/people/dr-olugbenga-a-mokuolu/">Professor Olugbenga A. Mokuolu </a>currently oversees all malaria work in Nigeria for Management Sciences for Health, a global health advisory organisation. He’s also the former technical director to the National Malaria Elimination Programme in Nigeria. Molecular parasitology Professor, Segun Isaac Oyedeji, spoke to him about Nigeria’s malaria burden.</em></p>
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<p><strong>Segun Oyedeji:</strong> Nigeria has a high malaria burden. How did it get here?</p>
<p><strong>Olugbenga Mokuolu:</strong> It’s a combination of many things.</p>
<p>The existence of malaria anywhere is an interaction between the environment and the organism responsible for the disease, the mosquito. When you look at an environment, you’re looking at a variety of natural factors – such as temperature, humidity and rainfall – and man-made factors, such as drainage systems. This is because certain conditions allow mosquitoes to thrive – specifically moisture-rich environments. Mosquitoes <a href="https://theconversation.com/heavy-rains-put-kenya-at-risk-of-mosquito-borne-diseases-130076">breed by laying</a> their eggs in stagnant water. </p>
<p>Nigeria’s environment is a favourable one in which mosquitoes – the malaria vector – can thrive. </p>
<p>In terms of environmental management, Nigeria leaves a lot to be desired. The country has open refuse sites, blocked drainage systems, and – because people lack piped water – they store water at home in containers. These all provide <a href="https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live.html">ideal sites</a> for mosquitoes to breed.</p>
<p>In terms of humidity, Nigeria has <a href="https://www.intechopen.com/chapters/65196">vegetation</a> that favours the reproductive stages of the parasite in the mosquito. <a href="https://pubmed.ncbi.nlm.nih.gov/14596287/#:%7E:text=The%20primary%20effect%20of%20increasing,at%20extraordinarily%20low%20vector%20densities.">Altitude also plays a role</a>. And, in most of Nigeria, the altitude allows the mosquito to fly around without much difficulty. Only the <a href="https://www.nigeriagalleria.com/Nigeria/States_Nigeria/Taraba/Mambilla-Plateau-Taraba.html">Mambilla Plateau</a> is considered relatively malaria free in Nigeria. It has an altitude that is above 5000 feet which makes it difficult for mosquitoes to inhabit. </p>
<p>In addition to this, Nigeria has a large population which makes malaria transmission much easier. Large populations mean more people tend to live closer together, which makes it easier for the mosquito vector to quickly find a contact for transmission of the malaria parasite. In addition, a large population puts more pressure on sanitation services, leading to more mosquito breeding sites. </p>
<p>That’s not to say no progress has been made. The country’s interventions have not been a failure altogether. My organisation is supporting Nigeria to provide preventive chemotherapy for malaria. We have reached over 25 million children under five in our intervention cycles. This is shown to have significant contribution to reduction in mortality. But we are not yet where we are supposed to be.</p>
<p><strong>Segun Oyedeji:</strong> Children are disproportionately affected. What can be done?</p>
<p><strong>Olugbenga Mokuolu:</strong> The Nigerian government and its partners have singled out children as the focus of most interventions. In addition, we need health system strengthening to address the gaps in access particularly at communities. </p>
<p>The Nigerian National Agency for Food and Drug Administration And Control <a href="https://www.nafdac.gov.ng/press-briefing-by-prof-mojisola-christianah-adeyeye-director-general-national-agency-for-food-and-drug-administration-and-control-nafdac-on-the-regulatory-approval-of-r21-malaria-vaccine-by-nafdac/">recently approved</a> the R21 malaria vaccine for use. </p>
<p>Hopefully when the R21 vaccine becomes available it will reduce new cases or the impact of cases. It is unclear when the vaccine may be rolled out in Nigeria. </p>
<p>A recent study shows that the <a href="https://www.ox.ac.uk/news/2023-04-13-r21matrix-m-malaria-vaccine-developed-university-oxford-receives-regulatory#:%7E:text=This%20followed%202021%20results%20from,and%20a%20reassuring%20safety%20profile.">R21 vaccine has some efficacy</a>. This vaccines has shown most effective when administered to children from five months to 36 months old. It is 77% effective in preventing infection and reduces the occurrence of severe malaria. Reducing the frequency of severe malaria reduces the burden of malaria mortality by extension. </p>
<p>The vaccines won’t be used on their own. They will be used as adjuncts to existing tools for fighting malaria such as preventative treatment and the distribution of bed nets.</p>
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Read more:
<a href="https://theconversation.com/what-nigeria-must-do-to-eliminate-malaria-three-researchers-offer-insights-159460">What Nigeria must do to eliminate malaria: three researchers offer insights</a>
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<p><strong>Segun Oyedeji:</strong> How can Nigeria reduce its malaria burden? </p>
<p><strong>Olugbenga Mokuolu:</strong> New cases of malaria can only be curbed by environmental measures, including the use of insecticide nets and personal protection. I know the vaccines aren’t 100% effective, but surely they will offer additional prevention. </p>
<p>But Nigeria needs to step up its game. The current <a href="https://drive.google.com/file/d/10da1qdiUbqxcZZHGa7uZxStnyFn9nFo-/view?pli=1">National Malaria Strategic Plan 2021 to 2025</a> is based on a well researched model. It is no longer business as usual. The plan clearly shows that if we don’t do more, malaria will keep rising. </p>
<p>But we are actually doing a lot.</p>
<p>Take the bed nets. These are being distributed on an almost regular basis to eligible states. Even COVID-19 didn’t stop the distribution. Now because of the size of Nigeria’s population, bed nets are distributed in what we call mass roll out campaigns with each state doing its own campaign. The improvement in malaria control that we have seen the last five to seven years is based on the intensity of interventions in two thirds of our states. </p>
<p>But Nigeria has gone further to almost be a global example, in how to implement <a href="https://www.who.int/teams/global-malaria-programme/prevention/preventive-chemotherapies">preventive chemotherapy</a>. We have 21 states out of 36 states where we reached over 25 million under five children in each cycle of intervention. We have four cycles in the year and this has contributed to reduction in mortality. </p>
<p>But we could do more. </p>
<p>Malaria isn’t going to be reduced significantly unless Nigeria intensifies development. Development plays a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856737/">major role</a> in reducing the burden. </p>
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<strong>
Read more:
<a href="https://theconversation.com/ending-malaria-in-africa-needs-to-focus-on-poverty-quick-fixes-wont-cut-it-169205">Ending malaria in Africa needs to focus on poverty: quick fixes won't cut it</a>
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<p>Also, infusion of funds and not just from the government. There is also public-private partnership for drug manufacturers. The government should give them a protected market and negotiate good prices. Let the manufacturers take over distribution using their own market principles in a manner that will be affordable to many people.</p>
<p>We need to look at new initiatives and also position ourselves in the vaccine game with respect to malaria. </p>
<p><strong>Segun Oyedeji:</strong> How can the international community – donors and aid agencies – best support Nigeria? </p>
<p><strong>Olugbenga Mokuolu:</strong> International partners are supporting the country in many ways. Largely the support is in funding and technical areas. Going forward, countries like Nigeria will need stronger support for consolidating current gains, new tools, health system strengthening, scaling up access to vaccine and local manufacturing or production of malaria intervention commodities.</p><img src="https://counter.theconversation.com/content/204148/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Segun Isaac Oyedeji receives funding from Deutscher Akademischer Austausch Dienst (DAAD), Tertiary Education Trust Fund (TETFUND).</span></em></p>
Nigeria must do more to reduce its high malaria burden.
Segun Isaac Oyedeji, Professor in Molecular Parasitology and Genetics, Federal University, Oye Ekiti
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/193233
2022-10-30T10:52:33Z
2022-10-30T10:52:33Z
Vaccines could be a game-changer in the fight against malaria in Africa
<figure><img src="https://images.theconversation.com/files/491862/original/file-20221026-13-1efpnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The first malaria vaccine, Mosquirix, was approved by the WHO in 2021.</span> <span class="attribution"><span class="source">Brian Ongoro/AFP via Getty Images</span></span></figcaption></figure><p>The development of an effective vaccine for malaria has proved to be far more challenging than developing a vaccine to protect people from COVID-19. Several different COVID-19 vaccines were <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/overview-COVID-19-vaccines.html">developed and approved</a> for use within a year of the disease’s emergence. </p>
<p>In contrast, it took over 30 years of intensive research and numerous clinical trials by the Walter Reed Army Institute of Research and partners before the <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">first malaria vaccine</a>, Mosquirix, was approved for use by the World Health Organization (WHO) in 2021. </p>
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Read more:
<a href="https://theconversation.com/malaria-vaccine-is-a-major-leap-forward-but-innovation-mustnt-stop-here-169639">Malaria vaccine is a major leap forward: but innovation mustn't stop here</a>
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<p>Creating a vaccine for a vector-borne disease such as malaria is very challenging. The parasite takes on <a href="https://www.dw.com/en/oxford-malaria-vaccine-promising-results-in-trials/a-63065352">different forms in different hosts</a>. And it’s constantly evolving to evade the human immune system and control interventions.</p>
<p>In a major step towards the equitable roll-out of Mosquirix, the WHO awarded the vaccine <a href="https://www.gsk.com/en-gb/media/press-releases/who-grants-prequalification-to-gsk-s-mosquirix-the-first-and-only-approved-malaria-vaccine/">prequalification status</a> in September 2022. The prequalification step follows approval. It ensures that only good quality products are procured and distributed by United Nations agencies and other major donors. </p>
<p>Most recently, researchers from Burkina Faso and Oxford University’s Jenner Institute – the same institution that developed the Oxford/AstraZeneca COVID-19 vaccine – made their own revelation. They <a href="https://www.bbc.com/news/health-62797776">released</a> very encouraging data from a clinical trial assessing the novel R21 malaria vaccine. </p>
<p>Like Mosquirix, the R21 vaccine targets the sporozoite. This is the malaria parasite stage that is transferred to humans when the malaria-infected female Anopheles mosquito is taking a blood meal. When effective, both vaccines ensure that the sporozoites are destroyed before they enter the liver. It effectively prevents malaria infection by halting the parasite life cycle in the human host.</p>
<p>The fight against malaria has been significantly strengthened with the addition of malaria vaccines to the suite of prevention measures. These vaccines have the potential to reduce malaria-related illness and and death in children under the age of five – one of the populations currently <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">most affected by malaria</a>. </p>
<h2>What studies show</h2>
<p>Both vaccines – Mosquirix and R21 – target the same parasite stage and use the same malaria proteins. But Oxford’s R21 vaccine contains a higher number of these malaria proteins. And it uses a different adjuvant – a chemical substance that stimulates the body’s immune response. These two factors are thought to improve the efficacy of the R21 vaccine by causing a stronger immune response. </p>
<p>The preliminary data are drawn from a <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00442-X/fulltext">two-year study</a> involving 409 children aged five to 17 months. The children received a booster dose 12 months after receiving the first three doses of the vaccine. The data suggest that the R21 vaccine resulted in a <a href="https://www.sabcnews.com/sabcnews/oxford-malaria-vaccine-data-bodes-well-for-effort-to-combat-deadly-disease/">higher level of protection</a> than Mosquirix. </p>
<p>Eight out of every 10 children who received four doses of the R21 vaccine did not develop malaria over the trial period – making this malaria vaccine the <a href="https://www.ox.ac.uk/news/2022-09-08-malaria-booster-vaccine-continues-meet-who-specified-75-efficacy-goal">first to meet the WHO minimum efficacy target</a> of 75% for 12 months in the target population of young African children.</p>
<p>These study results are encouraging. </p>
<p>But researchers have cautioned against a direct comparison between the performance of the R21 and Mosquirix vaccines. Unlike the Mosquirix vaccine, the R21 vaccine was given to children before the start of the malaria season. And it was only <a href="https://www.medicalnewstoday.com/articles/malaria-new-vaccine-candidate-shows-promise-in-clinical-trials#Plans-for-a-phase-3-trial">tested</a> on a small number of children from one region in Burkina Faso. In addition, a number of control and prevention measures were in place. </p>
<p>A larger study is needed to confirm vaccine efficacy in African children across the continent. This study must be done in regions with differing malaria transmission intensities, differing levels of malnutrition and anaemia in the target populations, and varying coverage of control interventions. </p>
<p>Four thousand eight hundred children from four African countries – two of which have malaria transmission all year round – have been enrolled in a <a href="https://www.nature.com/articles/d41586-022-02902-6">phase 3 clinical trial</a>. The aim of this trial is to demonstrate vaccine safety and efficacy in a larger, more diverse group of children. The researchers from the Jenner Institute expect the R21 vaccine to be approved for use next year, as long as no unexpected safety concerns are raised in this larger trial.</p>
<p>Manufacturing and distribution bottlenecks <a href="https://blogs.worldbank.org/health/new-data-illuminates-acute-vaccine-supply-delivery-gaps-developing-countries">prevented</a> the timely and equitable distribution of COVID-19 vaccines. To avoid a repeat, the University of Oxford has signed a manufacturing agreement with the Serum Institute of India, the largest manufacturer of vaccines globally. Under this agreement, the Serum Institute has agreed to supply at least 200 million doses annually. This is significantly more than the 15 million to 18 million doses of Mosquirix that GlaxoSmithKline is contracted to produce every year <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/oxford-malaria-vaccine-data-bodes-well-effort-combat-deadly-disease-2022-09-07/">until 2028</a>.</p>
<p>But, according to <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/why-worlds-first-malaria-shot-wont-reach-millions-children-who-need-it-2022-07-13/">the WHO</a>, this quantity is far lower than the projected demand for vaccines. To increase manufacturing capacity, the Jenner Institute is in talks with African vaccine manufacturers.</p>
<h2>Moving forward</h2>
<p>Getting the vaccines manufactured is only the first step. </p>
<p>Other hurdles include ensuring that countries can procure the vaccines, that there is equitable delivery of the vaccines to the requesting countries, and that there is prompt vaccines distribution to all healthcare facilities within the malaria risk areas. And most importantly, that there is optimal uptake of the vaccines.</p>
<p>Misinformation, <a href="https://www.phillyvoice.com/covid-19-vaccine-hesitancy-parents-children/">vaccine hesitancy</a> and safety concerns have contributed to a lower rate of vaccination against COVID-19, particularly among children. </p>
<p>For a malaria vaccine to have an impact, health promotion is key. Awareness campaigns must address safety concerns, while emphasising expected positive impacts of the vaccine. These campaigns must target both healthcare professionals and affected communities. They must be delivered before and during vaccine roll-out to ensure any new misinformation or concerns are promptly and effectively addressed.</p><img src="https://counter.theconversation.com/content/193233/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaishree Raman is affiliated with the National Institute for Communicable Diseases, the Wits Research Institute for Malaria and University of Pretoria's Institute for Sustainable Malaria Control and receives funding from the South African Research Trust, the Gates Foundation, the Global Fund, the Clinton Health Access Initiative, the South African Medical Research Council, and the National Institute for Communicable Diseases.</span></em></p>
For a malaria vaccine to have an impact, health promotion is key. Awareness campaigns must address safety concerns and emphasise expected positive impacts.
Jaishree Raman, Principal Medical Scientist and Head of Laboratory for Antimalarial Resistance Monitoring and Malaria Operational Research, National Institute for Communicable Diseases
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/168604
2021-11-15T14:10:58Z
2021-11-15T14:10:58Z
Some Nigerian plants show potential to treat malaria
<figure><img src="https://images.theconversation.com/files/423358/original/file-20210927-21-1w3gaaz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Malaria is endemic in Nigeria.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/children-run-with-advertising-banners-for-the-fight-against-news-photo/161362816?adppopup=true">Alexander Joe/AFP via Getty Images</a></span></figcaption></figure><p>Six countries in Africa accounted for about <a href="https://www.who.int/news-room/fact-sheets/detail/malaria">half</a> of all malaria deaths worldwide in 2019: Nigeria (23%), the Democratic Republic of the Congo (11%), Tanzania (5%), Burkina Faso (4%), Mozambique (4%) and Niger (4%).</p>
<p>The World Health Organization (WHO) has set an <a href="https://www.who.int/publications/i/item/9789240031357">ambitious target</a> of reducing the global malaria burden <a href="https://www.who.int/docs/default-source/documents/global-technical-strategy-for-malaria-2016-2030.pdf?sfvrsn=c82afcc_0">by 90% by 2030</a>. This is important work, given that malaria remains one of the world’s <a href="https://www.weforum.org/agenda/2020/04/covid-19-infectious-diseases-tuberculosis-measles-malaria/">deadliest infectious diseases</a>. The WHO <a href="https://www.who.int/data/gho/data/themes/malaria#:%7E:text=Globally%2C%20an%20estimated%203.4%20billion,getting%20malaria%20in%20a%20year">estimates</a> that 3.4 billion people in 92 countries are at high risk of being infected with malaria and 1.1 billion are at high risk of getting malaria in a year. </p>
<p>There has been some progress towards the 2030 goal, with both cases of and deaths from malaria <a href="https://www.who.int/news-room/feature-stories/detail/world-malaria-report-2019">dropping</a> from about 400,000 in 2010 to about 260,000 in 2018. But efforts are being hampered by the parasites <a href="https://www.nature.com/articles/d41586-021-02592-6?utm_source=Nature+Briefing&utm_campaign=821a738445-briefing-dy-20210924&utm_medium=email&utm_term=0_c9dfd39373-821a738445-45517738">resisting antimalarial drugs</a> that people take and by mosquitoes <a href="https://idpjournal.biomedcentral.com/articles/10.1186/s40249-019-0572-2">resisting insecticides</a>. While the WHO has <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">recommended</a> a vaccine for malaria, it is not yet accessible to all. </p>
<p>Researchers, myself among them, are also exploring alternative strategies to manage and treat malaria. I am studying whether plant-based remedies drawn from traditional medicinal practices may be of use. <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/210301">Herbs</a> are already used to treat diseases in many cultures. In <a href="http://www.bioline.org.br/pdf?tc07026">Nigeria</a>, as in other African countries and most parts of Asia, medicinal herbs are widely used to treat and prevent various ailments – including malaria.</p>
<p>Some current antimalarial drugs developed in laboratories, including amodiaquine and artemisinin, were either isolated from plants or were developed from chemical compounds found in plants. So it’s logical to investigate more plants and other natural products as potential sources of novel antimalarial agents. </p>
<p>Our <a href="https://pubmed.ncbi.nlm.nih.gov/33961995/">new study</a> examined whether extracts from a variety of plants were able to counter the effects of a malaria-causing parasite in mice – in other words, whether the plants treated malaria symptoms. We made a drink from three plants and gave it to mice infected with the <em>Plasmodium berghei</em> parasite.</p>
<p>We found a mixture of the herbs suppressed and prevented the presence of parasites inside the mice. This was more effective than each herb on its own. </p>
<h2>What we did</h2>
<p>A large number of medicinal plants are <a href="https://guardian.ng/sunday-magazine/living-wellbeing/herbal-cocktail-for-drug-resistant-malaria/">used</a> for treating malaria in Nigeria. This is common in the southern region of the country, where <a href="https://scied.ucar.edu/learning-zone/climate-change-impacts/vector-borne-disease">rainforests and a humid tropical climate</a> create ideal conditions for malaria transmission all year round. </p>
<p>One of the many groups of herbal remedies used in Nigeria is the antimalarial decoction popularly called <em>Agbo iba</em>. The composition, method of preparation and dosage of these antimalarial decoctions vary from vendor to vendor, as earlier <a href="http://gja.unilag.edu.ng/index.php/ujmst/article/view/367">reported</a> by my research group. These decoctions are often polyherbal (containing more than one herb) and prepared in water or alcohol. </p>
<p>For our experiment, we used <em>Mangifera indica</em>, (mango), <em>Azadirachta indica</em> (known in Nigeria as dongoyaro), <em>Nauclea latifolia</em> (African peach) and <em>Morinda lucida</em> (brimstone tree). They are all used traditionally in malaria treatment. </p>
<p>We bought the plants fresh from Mushin herbal market in Lagos and they were identified and authenticated at the herbarium of the Department of Botany, University of Lagos.</p>
<p>Mice are commonly used in preclinical trials because of biological similarities with humans. They can mimic malaria disease in humans and indicate how people might respond to the herbal mixture. </p>
<p>The study was conducted with approval from the Health Research Ethics Committee of the College of Medicine, University of Lagos. We inoculated the mice with chloroquine-sensitive <em>Plasmodium berghei</em>, obtained from the <a href="https://nimr.gov.ng/">Nigerian Institute of Medical Research</a>. </p>
<p>The animals were grouped and dosed to examine for three possible responses: preventing, suppressing and curing effects of the polyherbal mixture. Both prevention and suppression involve destroying the malaria parasite. Cure means the herbal mixtures eliminate the parasites.</p>
<h2>Our findings</h2>
<p>The mixture preparations gave promising antimalarial results in the three investigations. </p>
<p>In the prophylactic (prevention) test, the herbal decoctions demonstrated significant chemosuppression. Chemosuppression is the use of chemicals to defeat parasites in an animal. </p>
<p>All the herbal decoctions showed chemosuppressive activities. They significantly reduced the parasite load 24 hours after administration to the end of the treatment – four to seven days.</p>
<p>All the herbal decoctions were also active in the curative test. They considerably reduced the parasite load from day 2 of treatment. </p>
<p>At the end of treatment, none of the decoctions had completely cleared the parasites, but they all produced substantial clearance. This shows their potential usefulness against established plasmodial infection. </p>
<p>Our findings showed that the combination of all the plants could be useful in suppressing malaria in its early stages. All the decoctions investigated in this study could be considered as active antimalarial candidates. They could help with eradication of malaria parasites.</p>
<h2>Going forward</h2>
<p>Further studies will be needed to evaluate whether the polyherbal mixture we tested on mice is safe and effective in humans.</p>
<p>But this is a good starting point. The study shows that, with the right safety and clinical controls, the use of standardised herbal medicines could be a valid complementary approach for malaria management.</p>
<p>It’s good to find new medicines for malaria treatment because the parasites and microbes get used to the existing ones and become resistant. Medicinal plants are potential sources of new medicines.</p><img src="https://counter.theconversation.com/content/168604/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephanie Alaribe works for/consults to/owns shares in University of Lagos, Nigeria. She is affiliated with so many scientific bodies. </span></em></p>
A combination of herbs in Nigeria should be evaluated further as it offers potential to treat malaria, which is endemic in the country.
Stephanie Alaribe, Lecturer, University of Lagos
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/169639
2021-10-11T15:06:13Z
2021-10-11T15:06:13Z
Malaria vaccine is a major leap forward: but innovation mustn’t stop here
<figure><img src="https://images.theconversation.com/files/425668/original/file-20211011-18-73vdg2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A health worker prepares a malaria vaccination in Yala, Kenya</span> <span class="attribution"><span class="source">Brian Ongoro / AFP via Getty Images</span></span></figcaption></figure><p>The World Health Organisation (WHO) took an historic step in the fight against malaria when it recently recommended the use of a <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">malaria vaccine</a> for young children. The announcement marked a major achievement – the development of the first ever successful malaria vaccine against <em>falciparum</em> malaria, the deadliest form of malaria and the one that is most common in sub-Saharan Africa.</p>
<p>The wide uptake of the vaccine could prevent thousands of deaths in the region. According to the <a href="https://www.who.int/publications/i/item/9789240015791">2020 World Malaria Report</a>, over 250,000 children under the age of five years died of malaria in Africa in 2019. That is a very sombre statistic for a treatable and preventable disease.</p>
<p>The development of the vaccine (called RTS,S) has taken <a href="https://www.malariavaccine.org/sites/mvi/files/content/page/files/PATH_MVI_RTSS_Fact%20sheet_042019.pdf">over 30 years</a>. It is the culmination of work by researchers from the Walter Reed Army Institute of Research, in partnership with the pharmaceutical company GlaxoSmithKline and the global health organisation PATH.</p>
<p>Producing an effective malaria vaccine has been challenging as the malaria parasite is able to hide from the human immune system. In addition, different forms of the malaria parasite infect the liver and red blood cells. </p>
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Read more:
<a href="https://theconversation.com/why-does-malaria-recur-how-pieces-of-the-puzzle-are-slowly-being-filled-in-108833">Why does malaria recur? How pieces of the puzzle are slowly being filled in</a>
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<p>Vaccine trials were started in 2019 in three <a href="https://www.who.int/docs/default-source/immunization/mvip/mvip-milestones-to-programme-development-final.pdf?sfvrsn=14768db0_4">African countries</a> – Ghana, Kenya and Malawi. The study showed that the RTS,S vaccine was safe in young children, that it reduced hospitalisation and death in vaccinated children by over <a href="https://www.lshtm.ac.uk/newsevents/news/2021/severe-malaria-among-young-african-children-dramatically-reduced-through">70%</a>, and that a successful malaria vaccination programme was possible in rural African settings. </p>
<p>The pilot study also showed that the vaccine was able to reach children who were not being protected by other methods like bed nets in the <a href="https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-on-who-recommendation-for-wider-use-of-the-rts-s-malaria-vaccine">study sites</a>. This provided additional support to the calls for the widespread use of the vaccine in malaria-affected areas.</p>
<p><a href="https://www.who.int/publications/i/item/9789240015791">Since 2015</a> malaria case numbers have been either flat or on the rise. This follows 15 years during which the numbers had been on the decline.</p>
<p>The addition of the RTS,S vaccine to the malaria control and elimination toolkit could get global efforts back on track. But it cannot be viewed as the silver bullet required to achieve malaria elimination. </p>
<h2>Not a complete solution</h2>
<p>The vaccine has several <a href="https://www.tandfonline.com/doi/pdf/10.1080/21645515.2019.1669415?needAccess=true">shortcomings</a>. </p>
<p>Firstly, in its current form it only works very effectively in very young children, aged between five and 17 months. These children must be given three vaccine doses, at least one month apart. A fourth booster dose is recommended at 18 months for the vaccine to work optimally.</p>
<p>This is makes running an effective vaccination programme very challenging. One possible solution is using community-based vaccination programmes to increase access and improve compliance.</p>
<p>In addition, although the vaccine prevents severe disease, it doesn’t necessarily prevent infection. This is similar to the <a href="https://www.who.int/news-room/feature-stories/detail/vaccine-efficacy-effectiveness-and-protection">COVID-19 vaccines</a>. </p>
<p>Thirdly, it’s only effective against one (<em>Plasmodium falciparum</em>) of the five human malaria parasites. </p>
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Read more:
<a href="https://theconversation.com/breakthrough-malaria-vaccine-offers-to-reinvigorate-the-fight-against-the-disease-169500">Breakthrough malaria vaccine offers to reinvigorate the fight against the disease</a>
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<p>There are other concerns too. One is increased <a href="https://www.africaportal.org/features/myths-and-models-whats-driving-vaccine-hesitancy-in-africa-and-how-can-we-overcome-it/">vaccine hesitancy</a> across Africa.</p>
<p>There are also likely to be challenges in meeting the demand for vaccines, given the current focus on producing COVID-19 vaccines. </p>
<p>In light of these challenges, the RTS,S vaccine cannot replace existing effective interventions. These include indoor residual spraying and the use of insecticide treated bed nets. Instead, the vaccine must be used <a href="https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-on-who-recommendation-for-wider-use-of-the-rts-s-malaria-vaccine">alongside these</a> to break the malaria transmission cycle.</p>
<p>As the RTS,S vaccine is only effective in young children, it will only be used where they are at higher risk of infection than older children. Such conditions are generally found in <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">moderate to high transmission areas</a>. In these areas, frequent malaria infections result in older children developing partial immunity. </p>
<p>This immunity prevents children from showing the signs and symptoms of malaria. They become asymptomatic carriers of malaria. Many malaria-endemic African countries, including Botswana, Eswatini, Namibia and South Africa, have very low transmission intensities, so the population does not develop immunity against malaria. </p>
<p>Including the RTS,S vaccine in a childhood immunisation programme in these low transmission countries would not be cost-effective.</p>
<p>Despite the challenges associated with the RTS,S vaccine, its addition to the suite of malaria control interventions is a leap forward in the global fight against malaria. But vaccine innovation must not stop here. Efforts must be put into developing a vaccine that is effective in older children and adults, which requires only one dose and is effective against all human malarias.</p><img src="https://counter.theconversation.com/content/169639/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaishree Raman receives funding from the National Research Foundation of South Africa, the National Health Laboratory Services Research Trust and the Bill and Melinda Gates Foundation. She is affiliated with Centre for Emerging Zoonotic Diseases, National Institute for Communicable Diseases, the Wits Research for Malaria, University of Witwatersrand and the UP Institute for Sustainable Malaria Control, University of Pretoria.</span></em></p><p class="fine-print"><em><span>Shüné Oliver receives funding from the National Research Foundation of South Africa and the National Health Laboratory Services Services Research Trust. She is affiliated with Centre for Emerging Zoonotic Diseases, National Institute for Communicable Diseases and the Wits Research for Malaria, University of Witwatersrand</span></em></p>
The successful development of an effective vaccine against the deadliest form of malaria that is most common in sub-Saharan Africa is indeed a major achievement.
Jaishree Raman, Principal Medical Scientist and Head of Laboratory for Antimalarial Resistance Monitoring and Malaria Operational Research, National Institute for Communicable Diseases
Shüné Oliver, Medical scientist, National Institute for Communicable Diseases
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/169501
2021-10-08T18:22:32Z
2021-10-08T18:22:32Z
WHO approved a malaria vaccine for children – a global health expert explains why that is a big deal
<figure><img src="https://images.theconversation.com/files/425496/original/file-20211008-21-zm7jbr.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7719%2C5150&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A helping hand in the fight against malaria.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-this-photo-illustration-a-person-holds-two-vials-of-the-news-photo/1235759941?adppopup=true">Patrick Meinhardt/Getty Images</a></span></figcaption></figure><p><em>The World Health Organization <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">recommended its first malaria vaccine for children</a> on Oct. 6, 2021 – a breakthrough hailed by the U.N. agency as a “historic moment.”</em></p>
<p><em>Approval of the RTS,S/AS01 vaccine, which goes by the name Mosquirix, provides a “glimmer of hope” for Africa, according to Dr. Matshidiso Moeti, WHO regional director for Africa. It will now be rolled out to protect children against one of the world’s oldest and most deadly diseases.</em></p>
<p><em><a href="https://www.medschool.umaryland.edu/profiles/Laufer-Miriam/">Malaria and global child health expert</a> Dr. Miriam K. Laufer answered The Conversation’s questions about the vaccine and the WHO announcement.</em></p>
<h2>What has the WHO announced?</h2>
<p>The WHO has recommended the use of the RTS,S malaria vaccine, which is produced by GlaxoSmithKline. It is the first malaria vaccine to be recommended by the global health body.</p>
<p>It follows a review of two years of <a href="https://www.who.int/news/item/20-04-2021-rts-s-malaria-vaccine-reaches-more-than-650-000-children-in-ghana-kenya-and-malawi-through-groundbreaking-pilot-programme">piloting studies</a> of the vaccine in three sub-Saharan African countries with a high burden of malaria: Malawi, Kenya and Ghana. </p>
<p>After careful evaluation and extensive discussion, the WHO came to the consensus that the vaccine should be recommended for use in children living in areas of moderate to high malaria burden.</p>
<h2>Why is this seen as a major development?</h2>
<p>Malaria <a href="https://www.unicef.org/press-releases/ten-things-you-didnt-know-about-malaria#:%7E:text=Among%20all%20communicable%20diseases%2C%20malaria,young%20lives%20lost%20each%20day">kills hundred of thousands of children</a>, mostly in sub-Saharan Africa, every year. This is the first time that researchers, vaccine manufacturers, policymakers and advocates have successfully delivered a vaccine that has made it through clinical trials and received not only regulatory approval but also a recommendation from the WHO.</p>
<p>This vaccine prevents about 30% of severe malaria cases that are more likely to lead to death.</p>
<p>Although researchers knew that RTS,S was effective in well-controlled clinical trials, a few questions remained about whether it was feasible for sub-Saharan African countries to safely roll out the four-dose vaccine in a real-world setting. But since 2019, the <a href="https://www.who.int/initiatives/malaria-vaccine-implementation-programme">malaria vaccine implementation program</a> in Malawi, Kenya and Ghana has shown excellent vaccine uptake and a good safety profile. To date, the vaccine has been administered to around 800,000 children in those three countries. </p>
<h2>How big a killer is malaria?</h2>
<p>Malaria, a parasitic disease transmitted by bites from infected mosquitoes, causes nearly <a href="https://www.who.int/teams/global-malaria-programme/reports/world-malaria-report-2020">half a million deaths per year</a>, mostly in children in sub-Saharan Africa.</p>
<p>It is a disease that preys on the poorest of the poor. It causes the most disease and death in places where people lack access to basic health care, where housing conditions allow mosquitoes to enter and where inadequate water management provides breeding ground for mosquitoes. Despite international efforts to control it, the burden of malaria has continued and even increased over the past several years.</p>
<h2>How effective will the vaccine be compared to other treatments?</h2>
<p>We learned through the report of the trials to the WHO that the vaccine will be able to reach all children in areas of moderate to high risk of malaria. This will save lives from the deadly infection, especially among children with limited access to health services.</p>
<p>Prevention is almost always more cost-effective than treating disease, especially with an infection as common as malaria. Drugs are sometimes used to prevent malaria, but they have to be given frequently, which is both expensive and inconvenient.</p>
<p>In addition, the more often a drug is used, the more likely the malaria parasites will <a href="https://www.cdc.gov/malaria/malaria_worldwide/reduction/drug_resistance.html">develop resistance</a> to the drug.</p>
<h2>Why did it take so long to develop a vaccine?</h2>
<p>Lack of political will to develop a malaria vaccine certainly played a role in why it took so long. With no real market for a malaria vaccine in resource-rich countries like the U.S., pharmaceutical companies did not have a strong financial incentive to accelerate vaccine development.</p>
<p>But the malaria parasite is also very complex, and the targets of the immune system are diverse, so developing an effective vaccine wasn’t easy.</p>
<p>A vaccine developed against one malaria strain grown in the laboratory generally does not work against many of the malaria parasites that children encounter when bitten by infected mosquitoes, which is why even though RTS,S is a good vaccine, it protects against only 30% of infections.</p>
<p>If you think about this in terms of the COVID-19 vaccine, researchers developed a vaccine against the strain of the disease that was circulating in early 2020. But now we see that the vaccine does not protect people quite <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7034e4.htm?s_cid=mm7034e4_w">as well against the new delta variant</a>. Someday a variant may emerge that completely escapes the vaccine immune response.</p>
<p>For malaria, there are many variants of many different proteins, so finding a vaccine that covers all of these was a huge challenge.</p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/169501/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Miriam K. Laufer is affiliated with the WHO Malaria Vaccine Advisory Committee. This group was not involved in the recent RTS,S recommendation.</span></em></p>
Malaria is one of the world’s oldest and deadliest diseases. So why has it taken so long to get a vaccine?
Miriam K. Laufer, Professor of Pediatrics, Medicine, Epidemiology and Public Health at the Center for Vaccine Development and Global Health, University of Maryland
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/169500
2021-10-08T05:49:56Z
2021-10-08T05:49:56Z
Breakthrough malaria vaccine offers to reinvigorate the fight against the disease
<figure><img src="https://images.theconversation.com/files/425302/original/file-20211007-8006-x1dr4o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The first ever malaria vaccine promises to bring the battle against infections back on track.</span> <span class="attribution"><span class="source">Photo Illustration by Rafael Henrique/SOPA Images/LightRocket via Getty Images</span></span></figcaption></figure><p><em>The World Health Organization has announced a historic move: it has <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">recommended</a> the widespread use of the first ever malaria vaccine. The recommendation is based on the results of an ongoing <a href="https://theconversation.com/malawi-is-testing-a-new-malaria-vaccine-but-its-still-early-days-116007">pilot programme</a> in Malawi, Ghana and Kenya. Malaria is a huge global health challenge, around 409,000 people died of malaria in 2019 alone. The WHO African region carries significant proportion of the malaria burden – <a href="https://reliefweb.int/report/world/message-who-regional-director-africa-dr-matshidiso-moeti-world-malaria-day-2021#:%7E:text=In%202019%2C%20the%20WHO%20African,%25%20and%20deaths%20by%2060%25.">94%</a> of all malaria cases and deaths occurred in the region. Children younger than five are the most vulnerable. Ina Skosana asked Eunice Anyango Owino to explain the development, and its significance.</em></p>
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<h2>It has taken 30 years. Why so long?</h2>
<p>The most significant reason is that the malaria parasite is very complex. It has <a href="https://theconversation.com/why-does-malaria-recur-how-pieces-of-the-puzzle-are-slowly-being-filled-in-108833">different stages</a>; some in the mosquito and some in the human. Thus, scientists had to pursue a diversity of approaches. </p>
<p>For example, in the human there are two stages. These are the:</p>
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<li><p>Pre-erythrocytic stages (sporozoite, or spore-like, stage). This is the period when the parasite’s sporozoite from a mosquito bite enters the blood stream and heads for the liver to mature and multiply after which they are then released.</p></li>
<li><p>The blood stage (Merozoite stage). This is when the parasite’s merozoites are released from the liver, and multiply in the red blood cells.</p></li>
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<p>So an effective vaccine against the first stage (pre-erythroctic stage) would be one that elicits an immune response that would either prevent infection of the liver cells or lead to destruction of the infected liver cells. </p>
<p>An effective vaccine for the second stage (blood stage) would be the one that does one of three things: elicits immune responses that prevent infection of red blood cells; decreases the number of parasites in the blood; reduces the severity of the disease by allowing the body to develop a natural immunity with little risk of getting ill.</p>
<p>Another option was to develop transmission blocking vaccines. An effective transmission blocking vaccine would induce antibodies that would block maturation of malaria parasites in mosquitoes that feed on vaccinated individuals.</p>
<p>Another factor that contributed to the delay is that scientists working on malaria vaccines in the early stages lacked an understanding of the specific immune responses associated with protection against the parasite. </p>
<p>Also, malaria parasites – such as <em>Plasmodium falciparum</em> – display a variety of antigens on their surfaces that help them escape the immune system and also render vaccines based on specific antigens less effective. </p>
<h2>Can you tell us more about the vaccine?</h2>
<p>The vaccine RTS,S, trade name <a href="https://www.ema.europa.eu/en/opinion-medicine-use-outside-EU/human/mosquirix">Mosquirx</a>, is given in four doses to children between the ages of 5 months and 17 months; the first 3 doses are given monthly with the first at 5 months and the third at 9 months. The fourth, which is a booster dose, is given at between 15 and 18 months. </p>
<p>The <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">efficacy</a> is about 40% against malaria cases and 30% against severe malaria. </p>
<p>No two vaccines or diseases are comparable. The WHO has set an efficacy level of 50% and above for most vaccines and most highly efficacious vaccines offer 75 % and above level of protection. For example, the COVID-19 vaccines based on messenger (m)RNA technology by Pfizer and Moderna offer well above 90% protection level. </p>
<p>The RTS,S vaccine targets the parasites before they infect liver cells; it targets the circumsprorozoite protein on <em>P.falciparum</em> sporozoites surface and is thus considered a pre-erythrocytic vaccine.</p>
<h2>What are the next steps?</h2>
<p>First, the WHO and the manufacturers of the vaccine GlaxoSmithKline will be rallying countries, particularly those with high malaria burdens, to adopt the vaccine as part of their National Malaria Control Strategies.</p>
<p>They will also be asking these countries to set aside funds.</p>
<p>They will also be involved in fundraising from the global health community or work with partners, for a broader roll out of the vaccine. </p>
<p>There should be equitable and long term access to the vaccine. The vaccine should also be cost effective.</p>
<p>The hope is that the WHO announcement will re-energise the race to find even more efficient vaccines against malaria. Current <a href="https://www.ox.ac.uk/news/2021-05-07-promising-malaria-vaccine-enters-final-stage-clinical-testing-west-africa">reports</a> by the Jenner Institute of Oxford University suggest that a malaria vaccine that might meet the WHO goal of 75% is under trial in Burkina Faso.</p>
<h2>What does this mean for malaria control in Africa?</h2>
<p>The vaccine is an additional tool to the malaria control tool kit. </p>
<p>The vaccine does not provide complete protection. And will be introduced as part of a tool kit geared to reducing malaria infections and reducing fatalities. Other measures include bed nets and indoor residual spraying. </p>
<p>Nevertheless the vaccine has a great potential to reduce death and illness in high burden areas in sub-Saharan Africa especially if used in combination with pre-existing malaria prevention methods. For example a study by the London School of Tropical Medicine reported a <a href="https://www.lshtm.ac.uk/newsevents/news/2021/severe-malaria-among-young-african-children-dramatically-reduced-through">70% reduction</a> in hospitalisations and death in children given the Mosquirx vaccine plus antimalarial drugs.</p>
<p>Malaria control had been stagnating in some African countries, with countries like Sudan and Eritrea seeing a significant resurgence in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466923/">recent past</a>.</p>
<p>The vaccine will reinvigorate the fight against malaria. And it offers the promise of bringing it back on track.</p><img src="https://counter.theconversation.com/content/169500/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eunice Anyango Owino receives funding from the National Research Fund (NRF), Kenya.</span></em></p>
The WHO and the manufacturers of the vaccine will be rallying countries, particularly those with high malaria burdens, to adopt the vaccine.
Eunice Anyango Owino, Medical Entomologist at the School of Biological Sciences, University of Nairobi
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/169457
2021-10-08T03:30:35Z
2021-10-08T03:30:35Z
World’s first mass malaria vaccine rollout could prevent thousands of children dying
<p>The world’s first mass vaccination program against malaria, <a href="https://www.statnews.com/2021/10/06/in-major-decision-who-recommends-broad-rollout-of-worlds-first-malaria-vaccine">announced this week</a>, is set to prevent millions of children from catching malaria and thousands dying from this debilitating disease.</p>
<p>The World Health Organization (WHO) has <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">recommended</a> widespread use of the RTS,S/AS01 (Mosquirix) vaccine in young children who are most at risk of malaria in Africa.</p>
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<h2>Malaria is a big deal</h2>
<p>Mosquitoes spread the parasite <em>Plasmodium falciparum</em> from person to person when they bite. So until now, our fight against malaria has involved using mosquito nets to avoid being bitten and spraying insecticide to kill mosquitoes. Then there are drugs to prevent or treat malaria infection.</p>
<p>However, the parasite has developed resistance to antimalarial drugs and mosquitoes have developed resistance to insecticides. Nevertheless existing control measures have resulted in a <a href="https://www.who.int/publications/i/item/9789240015791">significant decrease</a> in the number of malaria deaths since 2000.</p>
<p>In recent years, however, progress has stalled. In 2019, malaria infection <a href="https://www.who.int/teams/global-malaria-programme/reports/world-malaria-report-2020">resulted in</a> 409,000 deaths around the world, mostly in children under five years old, and 229 million new malaria cases.</p>
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<a href="https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="African child under mosquito net" src="https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/425363/original/file-20211007-8006-xbtrf8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Mosquito nets only go so far. So other measures are needed to control malaria.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-african-boy-mosquito-net-protection-1812244213">Shutterstock</a></span>
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<p>So we need extra tools, such as an effective malaria vaccine, if we are to control the disease globally.</p>
<p>WHO’s recommendation to roll out the Mosquirix vaccine to children at high risk of infection with <em>P. falciparum</em>, which is widespread in Africa, is an important step towards controlling the deadliest of human malaria parasites.</p>
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Read more:
<a href="https://theconversation.com/how-our-red-blood-cells-keep-evolving-to-fight-malaria-96117">How our red blood cells keep evolving to fight malaria</a>
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<h2>What did the WHO recommend?</h2>
<p>The WHO recommended four doses of the vaccine in children from five months old.</p>
<p>This recommendation follows recent results from a <a href="https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk">pilot program</a> in Ghana, Kenya and Malawi, involving vaccinating more than 800,000 children since 2019. </p>
<p>The program showed delivering the vaccine is feasible and cost-effective in high-risk areas. It also increased the number of children (to more than 90%) who have access to at least one intervention to prevent malaria. </p>
<p>The vaccine has a good safety profile and reduces cases of clinical and severe malaria, which can be deadly.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/new-malaria-vaccine-proves-highly-effective-and-covid-shows-how-quickly-it-could-be-deployed-159585">New malaria vaccine proves highly effective – and COVID shows how quickly it could be deployed</a>
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</p>
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<h2>What do we know about the vaccine?</h2>
<p>Mosquirix is a “subunit” vaccine. This means it only contains a small part of the malaria parasite, which is produced as a synthetic protein. </p>
<p>This protein is coupled with an “adjuvant”, a molecule designed to stimulate a strong immune response.</p>
<p>The vaccine works mainly by stimulating the body to make antibodies against the parasite, neutralising it, and preventing it from entering liver cells. These are the first cells the parasite invades when it enters the body. </p>
<p>The vaccine also works by helping to mount an <a href="https://www.tandfonline.com/doi/full/10.1080/21645515.2017.1381809">inflammatory response</a>, when a different part of the immune system responds.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/male-mosquitoes-dont-want-your-blood-but-they-still-find-you-very-attractive-168751">Male mosquitoes don't want your blood, but they still find you very attractive</a>
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</em>
</p>
<hr>
<h2>The vaccine isn’t perfect</h2>
<p>The level of protection the vaccine provides isn’t ideal. Protection <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60721-8/fulltext">varies</a> with the age of the child when vaccinated, with less protection for young infants compared with older children. In the older children (5-17 months old), this averaged at about 36% protection against developing clinical malaria over a four-year period.</p>
<p>Protective immunity also decreases rapidly over time. This means regular booster doses will be required. Alternative immunisation schedules are also being evaluated.</p>
<p>Yet, the vaccine can still make a significant contribution to malaria control when used in areas of high malaria risk and with other control measures. </p>
<p><a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003377">One modelling study</a> estimated that in sub-Saharan Africa, Mosquirix could prevent up to 5.2 million cases of malaria and 27,000 deaths in young children each year.</p>
<h2>Why has it taken so long to get here?</h2>
<p>Developing a malaria vaccine is challenging. Technically, it is difficult to develop a vaccine against a parasite that lives in two hosts (mosquitoes and humans). </p>
<p>There has also been limited interest by pharmaceutical companies in developing a malaria vaccine.</p>
<p>Although travellers would benefit from a vaccine when travelling to affected countries, the people who most need a malaria vaccine live in some of the world’s poorest countries. So there is little financial incentive to develop a vaccine.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1445842940283129857"}"></div></p>
<p>Mosquirix is the result of more than 30 years of research and was created through a partnership between GlaxoSmithKline (GSK) and the Walter Reed Army Institute of Research in the USA.</p>
<p>This time-frame is not long considering both the antigen design and the adjuvant system were novel. </p>
<p>The Bill & Melinda Gates Foundation and GSK supported further development, including evaluating the vaccine in clinical trials. Over three decades, they invested <a href="https://www.nature.com/articles/d41586-019-01342-z">around US$700 million</a> to develop the vaccine.</p>
<h2>What next?</h2>
<p>This current version of Mosquirix is not expected to be the last.
<a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00943-0/fulltext">Preliminary results</a> for a new modified vaccine, called R21, are encouraging.</p>
<p>Other malaria vaccines in development include <a href="https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-018-1173-9">whole parasite vaccines</a>. These use the <a href="https://www.nature.com/articles/s41467-021-22740-w">whole malaria parasite</a> that has been killed or <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30104-4/fulltext">altered</a> so it cannot cause a malaria infection but can still stimulate an immune response. </p>
<p><a href="https://www.nejm.org/doi/10.1056/NEJMoa2034031?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">Passive vaccines</a> are also being investigated. These involve injecting long-lasting antibodies to prevent malaria infection.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-19-isnt-the-only-infectious-disease-scientists-are-trying-to-find-a-vaccine-for-here-are-3-others-145271">COVID-19 isn't the only infectious disease scientists are trying to find a vaccine for. Here are 3 others</a>
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</em>
</p>
<hr>
<h2>A whole new set of challenges</h2>
<p>In the meantime, WHO’s recommendation presents a new set of challenges. </p>
<p>Malaria-affected countries must decide whether to include Mosquirix as part of their national malaria control strategy. </p>
<p>Critical funding decisions from the global public health community will be needed to enable a broad rollout of the vaccine to the children who will most benefit from it. </p>
<p>Manufacturing capacity for tens of millions of doses each year, global vaccine supply chains and distribution infrastructure in malaria-affected countries will also be needed.</p>
<p>Finally, each country will need to maximise vaccine uptake and ensure completion of the four-dose immunisation schedule to obtain the vaccine’s full benefit.</p>
<p><em>Correction: This article originally said the Bill & Melinda Gates Foundation and GSK invested <a href="https://www.nature.com/articles/d41586-019-01342-z">around US$700,000 million</a> to support vaccine development, rather than US$700 million.</em></p><img src="https://counter.theconversation.com/content/169457/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Danielle Stanisic receives funding from the National Health and Medical Research Council, the Medical Research Future Fund, the National Foundation for Medical Research and Innovation and Rotary for the development of a whole parasite malaria vaccine.</span></em></p><p class="fine-print"><em><span>Michael Good receives funding from the National Health and Medical Research Council, the Medical Research Future Fund, the National Foundation for Medical Research and Innovation and Rotary for the development of a whole parasite malaria vaccine.</span></em></p>
But the vaccine isn’t perfect. So we’ll still need mosquito nets and insecticides too.
Danielle Stanisic, Associate Research Leader, Institute for Glycomics, Griffith University
Michael Good, Professor and NHMRC Investigator Fellow, Institute for Glycomics, Griffith University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/159460
2021-04-23T13:14:01Z
2021-04-23T13:14:01Z
What Nigeria must do to eliminate malaria: three researchers offer insights
<figure><img src="https://images.theconversation.com/files/396622/original/file-20210422-23-q4yulg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reliable and affordable tests are crucial in eliminating malaria </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/health-official-takes-blood-sample-of-a-woman-for-malaria-news-photo/522828816?adppopup=true">Pius Utomi Ekpei/AFP via Getty Images </a></span></figcaption></figure><p>Nigeria accounts for nearly a <a href="https://www.who.int/news-room/feature-stories/detail/world-malaria-report-2019">quarter</a> of deaths from malaria in the world – in 2018 the numbers stood at 95,000. Three of the country’s top malaria researchers reflect on why the numbers remain so high.</p>
<p>What does Nigeria need to do to eliminate malaria?</p>
<h2>Olukemi K. Amodu: research and innovate</h2>
<p>Malaria remains an important public health hazard globally. It is <a href="https://www.malariaconsortium.org/news-centre/pregnant-women-and-children-under-five-are-still-at-grave-risk-from-malaria-says-whoandrsquo-s-annual-report.htm#:%7E:text=According%20to%20the%20report%2C%20there,Africa%20were%20infected%20with%20malaria.">responsible</a> for high disease and death rates especially among children under five and pregnant women.</p>
<p>The malaria burden in Nigeria is high – <a href="https://www.who.int/news-room/feature-stories/detail/world-malaria-report-2019">25%</a> of cases globally. The causes include the climate, high transmission potential, socioeconomic development, an overstretched health care system and displaced populations.</p>
<p>Eliminating the disease will take sustained local funding and a strong political commitment at the federal and state levels. This requires a strong recognition of the risk to children and pregnant women.
The elimination plan must include focused research and strengthening health systems. It must also be population specific.</p>
<p>It must incorporate <a href="https://www.who.int/heli/risks/vectors/malariacontrol/en/">World Health Organisation-recommended</a> core interventions. One of these is vector control: protective measures such as insecticide treated materials, spraying to kill mosquito larvae and indoor spraying. The other is diagnostic testing and prompt treatment with effective medicines.</p>
<p>Nigeria needs sustained, interdisciplinary and multi-faceted research. This should be an interplay of basic sciences, clinical epidemiology, field epidemiology, social and behavioural studies. This will ultimately help in studying the differences and diversities in the population. Our federal government must invest more in this type of research.</p>
<p>Malaria prevalence data, clinical epidemiology, parasite diagnostics and rates are important tools for evaluating control efforts. Studies of population biology, genetics and density of the malaria parasite and vector will help find effective diagnostics, new indigenous drugs and new vector control methods. </p>
<p>There must be equal access to health management tools for malaria at all levels. This must embrace educating patent medicine sellers and incorporating knowledge of traditional or herbal medicine practices.</p>
<p>We need to develop new interventions for malaria control suitable for our population. </p>
<p>For example, people say insecticide treated nets are inconvenient, so we also need to develop new ways to use the available protective measures.</p>
<h2>Olusegun George Ademowo: beat the mosquitoes</h2>
<p>Efforts should be geared towards drastic reduction of contact between humans and mosquitoes. Surveillance is a very important component of malaria elimination.</p>
<p>Environmental management aims to control mosquitoes by removing their breeding sites and larvae. This can be done through clearing bushes around the house and other buildings. It’s important to dispose of broken pots and bottles, fix potholes on our roads and keep gutters clean.</p>
<p>We must also have reliable and affordable diagnostic means for detection of malaria parasites. The most user friendly is the rapid diagnostic test. It detects specific malaria antigens in a person’s blood if they are infected. The most sensitive tests should be identified and made available in health care facilities. They are needed in primary health care and recommended for home use. Expert microscopy should be used to validate the kits periodically.</p>
<p><a href="https://www.malariaconsortium.org/pages/112.htm">Artemisinin-based combination drugs</a> are the most acceptable for treatment. They should be made accessible and affordable. Special attention should be given to vulnerable groups: children, pregnant women and non-immune individuals visiting Nigeria from non-malarious countries.</p>
<p>The government must also be willing to eliminate malaria in Nigeria. <a href="https://health.gov.ng/doc/Final-NMEP-M_E-Plan-2014-2020-May-3rd-updated-09_05_16.pdf">The Malaria Elimination Programme</a> should be strengthened to evolve relevant home grown means to achieve its goals. The staff must be accountable and dedicated and a monitoring and evaluation system should be put in place.</p>
<h2>Segun Isaac Oyedeji: from nets to vaccines</h2>
<p><a href="https://www.reuters.com/article/us-africa-malaria-events-timeline-idUSKCN0YU0ER">In 1955</a>, the WHO launched the Global Malaria Eradication Programme to eradicate malaria globally. </p>
<p>But not all countries were involved in the programme. After some achieved elimination, its financiers stopped financial support and it stalled. Consequently, the responsibility to eliminate malaria now falls on individual countries. </p>
<p>To eliminate malaria in Nigeria, there must be sincere and sustained commitment by the government, policy makers and citizens. We must be ready to scale up existing malaria control measures and targeted interventions. </p>
<p>Available tools and strategies are currently targeted towards vector control, prompt and accurate diagnosis and effective treatment. These have enormous impact on malaria elimination programmes, succeeding in countries that have <a href="https://www.who.int/malaria/areas/elimination/malaria-free-countries/en/">eliminated malaria</a> and others at the pre-elimination phase. </p>
<p>The following control measures must be enforced and implemented:</p>
<p>We must ensure that at least 75% of the population use long-lasting insecticidal nets to kill or repel the mosquito that transmits the infection. This would give us “herd-protection” because mosquitoes would find less infected hosts and transmission of the parasite will reduce drastically. Those who have the nets must use them effectively. </p>
<p>We must make sure all pregnant women get treatment.</p>
<p>Government and policy makers may also consider the need for mass drug administration for the entire population at the same time.</p>
<p>Our health systems must be restructured, strengthened and made ready to face the challenges of malaria elimination.</p>
<p>Governments must commit to scale up funding for malaria control, the same way they aggressively pursued COVID-19 <a href="https://ncdc.gov.ng/diseases/guidelines">prevention and control</a>.</p>
<p>Development of an antimalarial vaccine will also be important for regional malaria elimination and future eradication effort. Getting a vaccine is a global effort and we are at <a href="https://www.gavi.org/gavi-statement-on-latest-trial-data-on-malaria-vaccine-candidate-rts-s?gclid=Cj0KCQjwvYSEBhDjARIsAJMn0liPzKALNoWuhGDC3jPl9d-7pOVC8AcZe2ttwKvndJJXNWP6J3D-fSAaAugEEALw_wcB">phase III trial</a> currently. Ghana, Kenya, Malawi, Tanzania and Mozambique are involved as study centres or trial sites.</p><img src="https://counter.theconversation.com/content/159460/count.gif" alt="The Conversation" width="1" height="1" />
Nigeria must invest more in research and incorporate World Health Organisation-recommended interventions to eliminate malaria.
Wale Fatade, Commissioning Editor: Nigeria
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/157858
2021-04-14T20:08:45Z
2021-04-14T20:08:45Z
3 mRNA vaccines researchers are working on (that aren’t COVID)
<figure><img src="https://images.theconversation.com/files/393919/original/file-20210408-21-8z0f13.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1000%2C561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/messenger-rna-mrna-strand-3d-rendering-1907619631">from www.shutterstock.com</a></span></figcaption></figure><p>The world’s first <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html">mRNA vaccines</a> — the COVID-19 vaccines from Pfizer/BioNTech and Moderna — have made it in record time from the laboratory, through successful clinical trials, regulatory approval and into people’s arms.</p>
<p>The high <a href="https://theconversation.com/how-effective-is-the-first-shot-of-the-pfizer-or-moderna-vaccine-156615">efficiency</a> of protection against severe disease, the <a href="https://theconversation.com/not-sure-about-the-pfizer-vaccine-now-its-been-approved-in-australia-you-can-scratch-these-4-concerns-straight-off-your-list-153719">safety</a> seen in clinical trials and the <a href="https://theconversation.com/less-than-a-year-to-develop-a-covid-vaccine-heres-why-you-shouldnt-be-alarmed-150414">speed</a> with which the vaccines were designed are <a href="https://www.nature.com/articles/nrd.2017.243">set to transform</a> how we develop vaccines in the future. </p>
<p>Once researchers have set up the mRNA manufacturing technology, they can potentially produce mRNA against any target. Manufacturing mRNA vaccines also does not need living cells, making them easier to produce than some other vaccines.</p>
<p>So mRNA vaccines could potentially be used to prevent a range of diseases, not just COVID-19.</p>
<h2>Remind me again, what’s mRNA?</h2>
<p><a href="https://theconversation.com/explainer-what-is-rna-15169">Messenger ribonucleic acid (or mRNA for short)</a> is a type of genetic material that tells your body how to make proteins. The two mRNA vaccines for SARS-CoV-2, the coronavirus that causes COVID-19, deliver fragments of this mRNA into your cells.</p>
<p>Once inside, your body uses instructions in the mRNA to make SARS-CoV-2 spike proteins. So when you encounter the virus’ spike proteins again, your body’s immune system will already have a head start in how to handle it.</p>
<p>So after COVID-19, which mRNA vaccines are researchers working on next? Here are three worth knowing about.</p>
<h2>1. Flu vaccine</h2>
<p>Currently, we need to formulate new versions of the flu vaccine each year to protect us from the <a href="https://theconversation.com/high-dose-immune-boosting-or-four-strain-a-guide-to-flu-vaccines-for-over-65s-112224">strains the World Health Organization (WHO) predicts</a> will be circulating in flu season. This is a constant race to monitor how the virus evolves and how it spreads in real time. </p>
<p>Moderna is already turning its attention to an <a href="https://investors.modernatx.com/news-releases/news-release-details/moderna-provides-business-update-and-announces-three-new">mRNA vaccine against seasonal influenza</a>. This would target the four seasonal strains of the virus the WHO predicts will be circulating.</p>
<p>But the holy grail is a <a href="https://asm.org/Articles/2019/August/A-Universal-Influenza-Vaccine-How-Close-Are-We">universal flu vaccine</a>. This would protect against all strains of the virus (not just <a href="https://theconversation.com/the-2019-flu-shot-isnt-perfect-but-its-still-our-best-defence-against-influenza-120088">what the WHO predicts</a>) and so wouldn’t need to be updated each year. The same researchers who pioneered mRNA vaccines are also <a href="https://www.sciencedirect.com/science/article/pii/S1525001620301994">working on a universal flu vaccine</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1379162134127448066"}"></div></p>
<p>The researchers used the vast amounts of data on the influenza genome to find the mRNA code for the most “highly conserved” structures of the virus. This is the mRNA least likely to mutate and lead to structural or functional changes in viral proteins. </p>
<p>They then prepared a mixture of mRNAs to express four different viral proteins. These included one on the stalk-like structure on the outside of the flu virus, two on the surface, and one hidden inside the virus particle. </p>
<p>Studies in mice show this experimental vaccine is <a href="https://www.sciencedirect.com/science/article/pii/S1525001620301994">remarkably potent</a> against diverse and difficult-to-target strains of influenza. This is a <a href="https://www.abc.net.au/news/health/2021-02-09/covid-19-vaccines-australia-mrna-medical-revolution/13132252">strong contender</a> as a universal <a href="https://www.pennmedicine.org/coronavirus/vaccine/qa-with-drew-weissman">flu vaccine</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-single-vaccine-to-beat-all-coronaviruses-sounds-impossible-but-scientists-are-already-working-on-one-156373">A single vaccine to beat all coronaviruses sounds impossible. But scientists are already working on one</a>
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<h2>2. Malaria vaccine</h2>
<p><a href="https://www.who.int/news-room/fact-sheets/detail/malaria">Malaria</a> arises through infection with the single-celled parasite <em>Plasmodium falciparum</em>, delivered when mosquitoes bite. There is no vaccine for it.</p>
<p>However, US researchers working with pharmaceutical company GSK have <a href="http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=20210030859.PGNR.&OS=DN/20210030859&RS=DN/20210030859">filed a patent</a> for an mRNA vaccine against malaria. </p>
<p>The mRNA in the vaccine codes for a <a href="https://www.nature.com/articles/s41467-018-05041-7">parasite protein</a> called PMIF. By teaching our bodies to target this protein, the aim is to train the immune system to eradicate the parasite.</p>
<p>There have been promising results of the experimental vaccine <a href="https://www.nature.com/articles/s41467-018-05041-7">in mice</a> and early-stage human trials are <a href="https://www.vox.com/future-perfect/22307700/malaria-rna-vaccines-covid-19">being planned</a> in the UK.</p>
<p>This malaria mRNA vaccine is an example of a <a href="https://www.nature.com/articles/s41434-020-00204-y">self-amplifying mRNA vaccine</a>. This means very small amounts of mRNA need to be made, packaged and delivered, as the mRNA will make more copies of itself once inside our cells. This is the next generation of mRNA vaccines after the “standard” mRNA vaccines seen so far against COVID-19.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/covid-19-isnt-the-only-infectious-disease-scientists-are-trying-to-find-a-vaccine-for-here-are-3-others-145271">COVID-19 isn't the only infectious disease scientists are trying to find a vaccine for. Here are 3 others</a>
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</p>
<hr>
<h2>3. Cancer vaccines</h2>
<p>We already have vaccines that prevent infection with viruses that cause cancer. For example, <a href="https://theconversation.com/we-have-a-vaccine-for-hepatitis-b-but-heres-why-we-still-need-a-cure-122861">hepatitis B vaccine</a> prevents some types of liver cancer and the <a href="https://www.health.gov.au/health-topics/immunisation/immunisation-services/human-papillomavirus-hpv-immunisation-service">human papillomavirus (HPV) vaccine</a> prevents cervical cancer. </p>
<p>But the flexibility of mRNA vaccines lets us think more broadly about tackling cancers not caused by viruses. </p>
<p>Some types of tumours have antigens or proteins not found in normal cells. If we could train our immune systems to identify these tumour-associated antigens then our immune cells could kill the cancer. </p>
<p>Cancer vaccines can be targeted to specific combinations of these antigens. BioNTech is developing one such mRNA vaccine that <a href="https://pubmed.ncbi.nlm.nih.gov/27281205/">shows promise</a> for people with advanced melanoma. CureVac has developed one for a specific type of lung cancer, with results from <a href="https://pubmed.ncbi.nlm.nih.gov/30736848/">early clinical trials</a>.</p>
<p>Then there’s the promise of personalised anti-cancer mRNA vaccines. If we could design an individualised vaccine specific to each patient’s tumour then we could train their immune system to fight their own individual cancer. Several research groups and companies <a href="https://www.youtube.com/watch?v=zM97kg7atWw">are working on this</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1378747738821566467"}"></div></p>
<h2>Yes, there are challenges ahead</h2>
<p>However, there are several hurdles to overcome before mRNA vaccines against other medical conditions are used more widely.</p>
<p>Current mRNA vaccines need to be <a href="https://www.abc.net.au/news/health/2021-04-12/pfizer-temperature-changes-transport-fridge-freezer/100062594">kept frozen</a>, limiting their use in developing countries or in remote areas. But Moderna is working on developing an mRNA vaccine that can be <a href="https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-longer-shelf-life-its-covid-19-vaccine#:%7E:text=The%20ability%20to%20store%20our,other%20parts%20of%20the%20world.%E2%80%9D">kept in a fridge</a>.</p>
<p>Researchers also need to look at how these vaccines are delivered into the body. While injecting into the muscle works for mRNA COVID-19 vaccines, delivery into a vein may be better for cancer vaccines. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/4-things-about-mrna-covid-vaccines-researchers-still-want-to-find-out-154160">4 things about mRNA COVID vaccines researchers still want to find out</a>
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</em>
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<p>The vaccines need to be shown to be safe and effective in large-scale human clinical trials, ahead of regulatory approval. However, as regulatory bodies around the world have already approved mRNA COVID-19 vaccines, there are far fewer regulatory hurdles than a year ago. </p>
<p>The high cost of personalised mRNA cancer vaccines may also be an issue.</p>
<p>Finally, not all countries have the facilities to make mRNA vaccines on a large scale, <a href="https://theconversation.com/australia-may-miss-out-on-several-covid-vaccines-if-it-cant-make-mrna-ones-locally-148996">including Australia</a>.</p>
<p>Regardless of these hurdles, mRNA vaccine technology has been described as <a href="https://www.tandfonline.com/doi/full/10.4161/hv.25181">disruptive</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3991152/">revolutionary</a>. If we can overcome these challenges, we can potentially change how we make vaccines now and into the future.</p><img src="https://counter.theconversation.com/content/157858/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Archa Fox receives funding from the Australian Research Council and the National Health and Medical Research Council. She is President of the RNA Network of Australia and an elected Director of the International RNA Society </span></em></p><p class="fine-print"><em><span>Damian Purcell receives funding from the National Health and Medical Research Council, and the Jack Ma Foundation. He is Past Presidents' advisor for the Australasian Virology Society, and Treasurer of the RNA Network of Australia,</span></em></p>
We have two mRNA COVID-19 vaccines so far. But what else can this technology do?
Archa Fox, Associate Professor and ARC Future Fellow, The University of Western Australia
Damian Purcell, Professor of virology and theme leader for viral infectious diseases, The Peter Doherty Institute for Infection and Immunity
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/147431
2020-10-19T15:07:57Z
2020-10-19T15:07:57Z
Malaria parasites in Nigeria are genetically diverse: a danger but also a useful tool
<figure><img src="https://images.theconversation.com/files/362148/original/file-20201007-20-ozffrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/protozoan-plasmodium-falciparum-in-the-stage-royalty-free-illustration/1193685708?adppopup=true">Kateryna Kon/Getty Images </a></span></figcaption></figure><p>Malaria is one of the world’s most dangerous <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6254980/">parasitic disease</a> and a major public health challenge, especially in Africa. </p>
<p>Each year, over <a href="https://www.who.int/publications/i/item/world-malaria-report-2019">200 million</a> new cases of malaria occur globally. This leads to the death of over 400,000 individuals, most of whom are children below the age of five. <a href="https://www.who.int/publications/i/item/world-malaria-report-2019">Nigeria accounts</a> for about a quarter of all malaria cases and deaths worldwide. </p>
<p>Malaria is caused by parasites of the genus <em>Plasmodium</em>. Humans acquire malaria when an infected female <em>Anopheles</em> mosquito bites an individual and injects <em>Plasmodium</em> parasites into the bloodstream. Five species of <em>Plasmodium</em> parasites are able to cause malaria in humans but the most dangerous and deadly is <em>Plasmodium falciparum</em>. It accounts for over <a href="http://apps.who.int/iris/bitstream/10665/200018/1/9789241565158_eng.pdf?ua=1">96%</a> of all <em>Plasmodium</em> species in Nigeria.</p>
<p>It has the ability to vary or mutate its genetic make-up, especially when under pressure, to generate diverse strains or <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000336">variants</a>. The result is enormous genetic diversity in natural populations. And this has consequences for malaria control and treatment. The high genetic diversity in the parasite population could lead to gradual selection of more virulent or powerful strains. That could lead in turn to the emergence and proliferation of <a href="https://www.nature.com/articles/s41598-019-50152-w">drug-resistant parasites</a>. </p>
<p>But the genetic diversity of malaria parasites is also a strong tool for monitoring the emergence, increase and spread of drug-resistant parasites. Scientists can use the information from the genetic differences to distinguish between parasites carrying drug-sensitive genotypes and those carrying drug-resistant genotypes.</p>
<p>Our research has already <a href="https://www.sciencedirect.com/science/article/pii/S1995764513601029?via%3Dihub">confirmed</a> that in malaria-endemic countries such as Nigeria, infected individuals carry <em>P. falciparum</em> parasites that are <a href="https://www.tandfonline.com/doi/abs/10.1179/136485908X252340">genetically complex or diverse</a>. What we didn’t know was how diverse the parasites are in the micro environment, such as within households and among children of the same family. </p>
<p>We thought that knowing the population structure within households could help us understand more about the pattern and development of the disease. It could also inform development of appropriate guidelines and control measures. </p>
<p><a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-020-03415-1">We found that</a> even in the micro environment, <em>P. falciparum</em> parasites exhibit high genetic diversity. This finding was similar to results from larger communities in malaria endemic regions and has the same important implications. The implication is that a one-size fits all intervention or approach against the parasites may not be effective. </p>
<h2>Different types in one home</h2>
<p>We <a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-020-03415-1">investigated </a> the genotypes of malaria parasite populations in children from 43 unrelated households or families in Lafia, North-central Nigeria. </p>
<p>We used a very sensitive molecular technique to determine parasite genotypes in each blood sample. We focused on a gene called MSP-2. This gene has two types, called FC27 and 3D7. Only one of these types (either FC27 or 3D7) is present in a single parasite at the stage when it enters a person’s blood.</p>
<p>Our findings showed that parasites in the study population carry genotypes containing both FC27 and 3D7. But the types were not uniformly distributed among the children in the study households. There were children living under the same roof and infected by parasites that were genetically different. This diversity could help explain why siblings of the same household experience different disease patterns or outcomes. The genetic differences in the parasites could also make the children respond differently to treatment as some children may carry drug-sensitive parasites while others carry drug-resistant parasites.</p>
<p>In some households, all the infected children may have parasites carrying mixed genotypes of both FC27 and 3D7 alleles – two parasite genotypes in one child. In other households, one of the children could be infected with parasites carrying FC27, while another child would have parasites carrying another genotype. In a few households, all the children had infection with parasites carrying genotype of only one MSP-2 type (either FC27 or 3D7), which may suggest inoculation by a single or related mosquito.</p>
<h2>Implications of our findings</h2>
<p>High genetic diversity of <em>P. falciparum</em> populations in an area is an indication that malaria transmission in the area is high. This can lead to competition for survival in the parasite population. That may in turn lead to the emergence of mutant parasites, gradual selection and spread of more virulent strains. These strains would have acquired mutation in genes associated with resistance, especially when under drug or immune selection pressure. </p>
<p>Genetic diversity of the parasite population may also be a tool for surveillance and monitoring of the status or emergence of drug-resistant parasites in a community. </p>
<p>Parasites that become drug-resistant through mutation may <a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002450">increase the risk of treatment failure</a>. The relationship is not direct, though, and remains to be established. </p>
<p>Similarly, genetic diversity could be a challenge for developing a malaria vaccine. A vaccine is designed to target a particular antigen, the substance that causes the human body to recognise and fight an infection. If the parasite has several other antigens, the vaccine won’t work for them all.</p>
<p>Genetic diversity also matters when it comes to diagnosing malaria. The blood test kit is looking for a particular feature in the parasite’s genes. If the feature is slightly different from the standard, it <a href="https://www.clinicalmicrobiologyandinfection.com/article/S1198-743X(18)30631-1/fulltext">won’t be</a> picked up.</p>
<h2>Conclusion</h2>
<p>Our studies have shown that <em>P. falciparum</em> parasites exhibit high genetic diversity in natural populations, including the micro environment, in areas where malaria transmission is high. </p>
<p>Genetic diversity is a survival strategy the parasites use to escape from host immune defences and fight against malaria control interventions. But it is also a way to keep a watch for mutants that may be resistant to drugs. And it’s a tool for evaluating intervention programmes.</p><img src="https://counter.theconversation.com/content/147431/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Segun Isaac Oyedeji receives funding from:
Deutscher Akademischer Austausch Dienst (DAAD), Germany.
International Centre for Theoretical Physics (ICTP) Trieste, Italy.
International Centre for Theoretical Science (ICTS) Bengaluru, India.
</span></em></p>
Genetic diversity of a parasite population might help us watch for drug-resistant parasites.
Segun Isaac Oyedeji, Lecturer, Federal University, Oye Ekiti
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/137502
2020-04-30T15:56:53Z
2020-04-30T15:56:53Z
Why a campaign to champion all vaccines matters now more than ever
<figure><img src="https://images.theconversation.com/files/331369/original/file-20200429-51513-9xywtf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vaccines are some of the most equitable and cost-effective health interventions available.
</span> <span class="attribution"><span class="source"> ranplett/GettyImages</span></span></figcaption></figure><p><a href="https://www.who.int/news-room/campaigns/world-immunization-week/world-immunization-week-2020">World Immunisation Week</a> is celebrated in the last week of April every year. The aim is to recognise efforts to develop new vaccines and increase vaccination coverage worldwide. The World Health Organisation (WHO) also uses the week to galvanise national and international communities to keep pushing for more: greater demand for vaccines, better access, equity and higher coverage.</p>
<p>Vaccines are some of the most equitable and cost-effective health interventions available. As global attention is captured by the COVID-19 pandemic, the campaign to champion all vaccines matters now more than ever.</p>
<h2>Lives saved due to immunisation</h2>
<p>The world before vaccination was a very different place. On the African continent, before a <a href="https://www.afro.who.int/health-topics/yellow-fever">yellow fever</a> vaccine was developed and routinely delivered (as recommended by the WHO in 1988), epidemics occurred every three to 10 years. Up to a quarter of those showing symptoms would get severe disease and among those with severe disease, half would die. Outbreaks still occur in at-risk areas where vaccination services have broken down. But if the vaccine is available, 99% of people who get it are protected within 30 days of the injection and will survive.</p>
<p>Similarly with measles, between 2000 and 2018 the vaccination is estimated to have prevented <a href="https://www.who.int/news-room/fact-sheets/detail/measles">23 million deaths</a> worldwide. In the 1960s, before widespread vaccination, measles epidemics used to occur every two or three years, not only causing millions of deaths, usually in children, but also long-term disabilities. Measles can attack every organ in the body, and even after recovering from the illness, children can be left blind or deaf, with <a href="https://science.sciencemag.org/content/366/6465/599">detrimental effects</a> on their immune systems. </p>
<p>There have been substantial gains in measles prevention. But there were still 140,000 measles <a href="https://www.who.int/news-room/detail/05-12-2019-more-than-140-000-die-from-measles-as-cases-surge-worldwide">deaths</a> worldwide in 2018 due to pockets of unvaccinated children transmitting the disease. In the African region alone, the WHO <a href="https://www.who.int/news-room/detail/05-12-2019-more-than-140-000-die-from-measles-as-cases-surge-worldwide">estimates</a> there were 1.7 million cases of illness and 50,000 deaths in 2018 . </p>
<p>While calling for a COVID-19 vaccine we must remember to ensure that the highly effective vaccines in our existing armoury, like the one for measles, continue to be made available for all who need them. COVID-19 provides a stark reminder of what a world without vaccines would look like.</p>
<h2>Limitations</h2>
<p>If vaccines are so effective, why don’t we have them for all diseases?</p>
<p>HIV and malaria are “hard hitters” on the African continent and have been for decades, so why are there still no vaccines available? </p>
<p>A large part of the challenge boils down to how rapidly these germs can change their identity. Vaccines aim to simulate a natural infection, so that when a true infection comes along, your body can recognise the germ quickly and launch the correct response to disarm it. They are, in that way, one of the most “natural” medical interventions you could think of. Essentially they just prepare your own immune system to react more effectively than it would if coming into contact with the germ for the very first time.</p>
<p>The route to developing an effective vaccine, therefore, depends on the nature of the germ itself, how your natural immune system responds to it and the safety of different possible types of vaccine material. Unfortunately, both malaria and HIV are highly complex organisms that can rapidly change the way they “look” to your immune system. This makes it hard to make a vaccine, as the organism itself is constantly changing and has inbuilt ways to evade recognition by your immune system.</p>
<p>The safety of potential vaccines is also crucial. Research moves sequentially from “test-tubes” to animals and, if it meets all the criteria indicating that it is safe, then the trials move to include a small number of healthy adults. Gradually, the number and diversity of those included in trials is expanded, until enough safety and efficacy data are accrued to pass it through to the next stage of development. </p>
<p>There is a huge amount of ongoing research to identify possible “candidate” vaccines for both HIV and malaria (and COVID-19). A few malaria vaccine candidates have looked promising and there is a large scale implementation trial of the <a href="https://www.malariavaccine.org/malaria-and-vaccines/rtss">RTSS malaria vaccine</a> to demonstrate effectiveness; researchers are <a href="https://www.tandfonline.com/doi/abs/10.1080/14760584.2019.1561289?journalCode=ierv20&">optimistic</a>. Despite testing a large number of HIV vaccine candidates in the past few decades, they have failed to demonstrate efficacy, and the search continues. </p>
<p>But the frustration from decades of failed attempts should not reduce the rigour of the research needed. The vaccine development process has to be long enough to ensure the end product is safe. Continued focus on developing new vaccines is needed, alongside patience and political will to get them to the populations that need them most when they do become available.</p>
<h2>Remaining challenges: access and attitudes</h2>
<p>“Getting vaccines to the populations that need them most” encompasses a range of problems. The WHO <a href="https://www.who.int/news-room/fact-sheets/detail/immunization-coverage">estimates</a> that in 2018, 20 million children remained unvaccinated or under-vaccinated. That is, they had not completed the full course of recommended vaccinations by the time they reached one year of age. That is one in every seven infants worldwide. </p>
<p>This statistic hides considerable complexity. The number varies by vaccine, across countries and within countries.</p>
<p>Leaving a proportion of the population under-vaccinated doesn’t just affect those individuals, it reduces herd protection. Herd protection is the effect achieved by vaccinating most people in the “herd” and therefore reducing transmission of the infection to such an extent that the remainder don’t come into contact with it. This protects vulnerable people who cannot be vaccinated because they are too young or have certain health conditions. </p>
<p>Pockets of under-vaccinated people put themselves and others at risk as they act as reservoirs for transmission of the infection.</p>
<p>Vaccine hesitancy or “anti-vax” sentiment has become a growing issue, to the extent that the WHO considered it one of the <a href="https://www.who.int/news-room/feature-stories/ten-threats-to-global-health-in-2019">top 10 threats to global health in 2019</a>. It is still relatively rare in Africa, but it has arisen recently in populations more sceptical of health authorities and for whom the memories of uncontrolled infection have disappeared. </p>
<p>It must be guarded against, especially in the uncertain times of COVID-19. A global pandemic like this one threatens to reverse the victories that are won every day over vaccine-preventable diseases in low-income settings, including gains towards <a href="https://www.sciencemag.org/news/2020/04/polio-measles-other-diseases-set-surge-covid-19-forces-suspension-vaccination-campaigns">polio eradication</a>. </p>
<p>The pandemic reduces the staff and resources available to continue routine immunisation services as resources are redirected to COVID-19 wards. Uncertainty over whether services are continuing as many workplaces are temporarily shut down, together with reduced transport options, makes it harder for parents to access care. </p>
<p>Fear of contracting the virus in transit or while at the health facility may additionally prevent parents from bringing children to the health centre. If the uptake of vaccines does drop, outbreaks of vaccine preventable diseases such as bacterial meningitis and pneumonia, measles, rotavirus diarrhoea and others will cause even higher rates of death when patients present to a health system that is already straining under the weight of COVID. </p>
<p>Now more than ever, routine vaccination must continue. The WHO has released <a href="https://www.who.int/immunization/news_guidance_immunization_services_during_COVID-19/en/">guidelines</a> on maintaining routine immunisation services during the COVID-19 pandemic. While everyone has their eyes on the coronavirus pandemic, it is vitally important that national immunisation programmes, front line health workers and parents find a way to sustain the routine immunisation system and continue to save millions of children’s lives.</p><img src="https://counter.theconversation.com/content/137502/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katherine E. Gallagher receives funding from the Bill & Melinda Gates Foundation and the United Kingdom National Institute for Health Research. </span></em></p><p class="fine-print"><em><span>I have received funding for vaccine related research from Gavi, The Vaccine Alliance; the Bill & Melinda Gates Foundation; The Wellcome Trust; The Medical Research Council of the UK; the National Institute of Health Research; PATH Vaccine Solutions.
</span></em></p><p class="fine-print"><em><span>Ifedayo Adetifa receives funding from the following: United Kingdom's Medical Research Council, Department for International Development and National Institute for Health Research, and from Gavi, The Vaccine Alliance. </span></em></p><p class="fine-print"><em><span>John Ojal receives funding from National Institute for Health Research (NIHR) Global Health Research Unit on Mucosal Pathogens using UK aid from the UK Government.</span></em></p><p class="fine-print"><em><span>Shirine Voller is Programme Manager on a project funded by Gavi, the Vaccine Alliance </span></em></p><p class="fine-print"><em><span>Wangeci Kagucia is a co-investigator on a project funded by Gavi, The Vaccine Alliance. </span></em></p>
Coronavirus is a stark reminder of what a world without vaccines would look like.
Katherine E. Gallagher, Assistant Professor of Epidemiology, London School of Hygiene & Tropical Medicine
Anthony Scott, Professor of Vaccine Epidemiology, Director HPRU in Immunisation, London School of Hygiene & Tropical Medicine
Ifedayo Adetifa, Associate Professor, London School of Hygiene and Tropical Medicine, United Kingdom & Clinical Epidemiologist, KEMRI Wellcome Trust Research Programme
John Ojal, Research Fellow in Infectious Disease Modelling, NIHR Mucosal Pathogens Research Unit, London School of Hygiene & Tropical Medicine
Shirine Voller, ED Programme Manager, KEMRI Wellcome Trust Research Programme
Wangeci Kagucia, Research Fellow, KEMRI Wellcome Trust Research Programme
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/116263
2019-06-27T03:31:46Z
2019-06-27T03:31:46Z
Infecting healthy people in vaccine research can be ethical and necessary
<figure><img src="https://images.theconversation.com/files/278473/original/file-20190607-52762-rsjii1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Human challenge studies can be useful to test new vaccines and are increasingly being used internationally. Yet there are several ethical issues to consider.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/181674146?src=XTw248nYCP_PwgL1Gs9HJQ-1-11&studio=1&size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p>Medical experiments involving intentionally infecting people with bacteria, viruses, and parasites are surprisingly common. And they are becoming more common worldwide, particularly in developing countries.</p>
<p>The ultimate aim of these “human challenge studies” is usually to test potential new vaccines.</p>
<p>However, because of the risks involved, this kind of research raises difficult ethical questions. For example, who should be infected? And which pathogens would be too dangerous to use?</p>
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Read more:
<a href="https://theconversation.com/care-and-consent-the-fraught-ethics-of-international-clinical-trials-12602">Care and consent: the fraught ethics of international clinical trials</a>
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<p>In many challenge studies, people are first vaccinated with an experimental vaccine, then deliberately exposed to a pathogen and monitored to see if the vaccine protected them against infection.</p>
<p>These studies can be especially valuable from a scientific perspective. They can be significantly <a href="https://www.ncbi.nlm.nih.gov/pubmed/21179119">faster and less expensive</a> than other kinds of vaccine research. They are also usually much smaller, because <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6215823/">fewer people</a> need to be given experimental vaccines (that might not turn out to be safe or effective).</p>
<p>These studies sometimes involve infecting people with deadly diseases such as <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038434">malaria</a>. In such cases, however, researchers are especially careful to minimise risks by ensuring study participants are provided with treatment.</p>
<h2>How can this be ethical?</h2>
<p>The very idea of intentionally infecting humans with diseases will likely strike many people as unethical. </p>
<p>The history of human challenge studies is <a href="https://global.oup.com/academic/product/the-oxford-textbook-of-clinical-research-ethics-9780199768639?q=oxford%20textbook%20research%20ethics&lang=en&cc=au#">tarnished</a>. Some of the most blatantly unethical medical research ever conducted involved intentional infection. During world war two, for example, German and Japanese researchers infected prisoners with diseases such as tuberculosis and plague, killing them in the process.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/two-steps-forward-one-step-back-how-world-war-ii-changed-how-we-do-human-research-39929">Two steps forward, one step back: how World War II changed how we do human research</a>
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<p>According to most bioethicists who have discussed this topic, however, intentionally infecting people in a clinical trials isn’t necessarily unethical, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5926904/">at least under certain conditions</a>.</p>
<p>Rather than intentional infection, the problem with the infamous historical cases is they involved cruel and brutal treatment of people against their will.</p>
<p>But human challenge studies can be ethically acceptable so long as we meet <a href="https://www.wma.net/policies-post/wma-declaration-of-helsinki-ethical-principles-for-medical-research-involving-human-subjects/">basic research ethics requirements</a>. </p>
<p>Among other things, this should involve proper informed consent and minimising risks. There should also be legitimate scientific reasons for performing the study.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/human-experiments-the-good-the-bad-and-the-ugly-39876">Human experiments – the good, the bad, and the ugly</a>
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</p>
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<p>Modern human challenge studies are regularly approved by research ethics committees. They have been <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(15)00068-7/fulltext">safely conducted</a> with no deaths or severe lasting harms.</p>
<p>Other types of research with healthy volunteers are sometimes more dangerous. One UK trial of an <a href="https://www.bbc.com/news/magazine-35766627">experimental drug</a> had life-threatening consequences for six volunteers. One reportedly remained in hospital for four months, and all his toes had to be amputated. By comparison, infections in challenge studies are usually much more predictable and easier to treat.</p>
<h2>Should this occur in developing countries?</h2>
<p>Most recent human challenges studies have taken place in wealthy, developed nations. This might partly reflect the aim of scientists to avoid conducting experiments on especially vulnerable people in developing countries.</p>
<p>But a recent development is the expansion of human challenge studies into low- and middle-income countries – such as Thailand, Colombia, Kenya (and other African countries) – where diseases of interest are more common.</p>
<p>One motivation for this shift is to obtain results more relevant to the populations in these countries. For instance, the diseases and/or vaccines might affect these populations differently to people in developed nations due to variation in immunity, genetics or nutrition.</p>
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Read more:
<a href="https://theconversation.com/how-researchers-assess-whether-medications-work-102773">How researchers assess whether medications work</a>
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<p>Beyond being merely permissible, there may be an ethical imperative to <a href="https://ijme.in/articles/ethical-challenges-posed-by-human-infection-challenge-studies-in-endemic-settings/?galley=html">conduct more challenge studies in countries where the target disease is endemic</a> or widespread.</p>
<p>The fact that participants from endemic countries are more likely to be partially immune to diseases being studied means that conducting local challenge studies might involve less risk to them. </p>
<p>Studies can also sometimes directly benefit trial participants. That’s because infection during a study can lead to immunity against a disease to which they otherwise would have been at risk, or because they receive a vaccine that protects them. </p>
<p>Such benefits do not usually result when challenge studies are conducted in rich countries where the disease does not normally occur.</p>
<h2>What ethical issues remain?</h2>
<p>Though human challenge studies can be ethical – even in low- and middle-income countries – there are numerous unresolved issues about the conditions under which this kind of research should be conducted.</p>
<p><strong>Who should take part in these studies?</strong> </p>
<p>Some studies have aimed to <a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-015-0671-x">recruit university students</a> because, being more educated, they may be better able to provide adequate informed consent. But students might not provide a good representative sample of the general population, or they might feel pressure to participate in research being conducted at their institutions or by their academic superiors.</p>
<p><strong>How much should participants be paid?</strong></p>
<p>It is generally agreed that subjects should <a href="https://www.nejm.org/doi/full/10.1056/NEJMsb1710591">be paid for the costs they incur</a> while taking part in a study. This might include the costs of travel or loss of usual income. </p>
<p>Whether, or the extent to which, they should receive further payments reflecting the risks or other burdens endured, is more controversial. </p>
<p>Some say <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/bioe.12596">higher levels of payment</a> reflecting burdens or risks endured would be appropriate, just as some workers receive higher pay for doing dangerous jobs. </p>
<p>Others <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4214066/">worry</a> that high levels of payment might be an irresistible lure, especially for poor people. It appears that <a href="https://www.telegraph.co.uk/news/0/students-paid-3500-catch-potentially-deadly-diseases-science/">payment has been a major motivation</a> for people to participate in challenge studies in both <a href="https://journals.sagepub.com/doi/abs/10.1177/1556264618820219">high-income</a> and <a href="https://wellcomeopenresearch.org/articles/3-39/v2">low-income</a> countries. </p>
<p><strong>Should children be involved?</strong></p>
<p>Would it ever be acceptable to involve children in challenge studies?</p>
<p>Because diseases and/or vaccines might affect children differently, conducting research with adults might not always provide reliable enough information about the safety and efficacy of vaccines for children.</p>
<p>But children are widely considered especially vulnerable because, among other reasons, they cannot provide informed consent.</p>
<p><strong>Are there some pathogens that should never be tested?</strong></p>
<p>In general, challenge studies involving high risks that cannot be easily controlled should presumably not be permitted. The use of pathogens <a href="https://wellcomeopenresearch.org/articles/3-39/v2">like HIV</a>, for example, should be off limits.</p>
<h2>In a nutshell</h2>
<p>Human challenge studies are sometimes ethically acceptable. And it may be important to conduct them, especially in low- and middle-income countries where neglected diseases are most common. </p>
<p>Yet we still need bioethicists, policymakers and the general public to discuss unresolved ethical questions about where, when and how they should be conducted.</p><img src="https://counter.theconversation.com/content/116263/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was supported by the Wellcome Trust (210551/Z/18/Z)</span></em></p>
Deliberately infecting people with a disease-causing agent as part of carefully considered medical research can be ethically acceptable or even necessary.
Michael Selgelid, Director, Centre for Human Bioethics; Director, World Health Organization Collaborating Centre for Bioethics, Monash University
Euzebiusz Jamrozik, PhD Candidate, Centre for Human Bioethics, Monash University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/116007
2019-04-30T09:05:52Z
2019-04-30T09:05:52Z
Malawi is testing a new malaria vaccine. But it’s still early days
<figure><img src="https://images.theconversation.com/files/270990/original/file-20190425-121228-1lfp0zl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=18761">CDC/ James Gathany</a></span></figcaption></figure><p><em>Malaria is a leading <a href="https://www.who.int/malaria/media/world-malaria-report-2018/en/">cause of death</a> and illness around the world. Over 200 million cases are reported every year, and more than 400 000 people <a href="https://www.who.int/malaria/media/world-malaria-report-2018/en/">die</a>. More than 90% of cases are reported in sub-Saharan Africa. Scientists have spent decades searching for an effective vaccine. Hence the recent excitement when Malawi’s government announced it had <a href="https://www.who.int/news-room/detail/23-04-2019-malaria-vaccine-pilot-launched-in-malawi">launched</a> a pilot programme for the world’s first malaria vaccine, RTS,S (also known as Mosquirix©), produced by the pharmaceutical company, GSK. It’s the first vaccine to demonstrate significant reduction in malaria in children. The Conversation Africa’s Ina Skosana asked immunologist Faith Osier about RTS,S.</em></p>
<p><strong>Why is this vaccine a big deal?</strong></p>
<p>This marks a major milestone in the history of malaria vaccine development. Although many strategies are under investigation, few have been successful enough to get tested in early clinical trials in humans. </p>
<p>RTS,S is the first malaria vaccine that has shown some protection in large scale clinical research studies. Almost all the previous vaccine candidates that have previously made it to clinical trials in humans failed to induce sufficient levels of protection. </p>
<p>Now that it’s jumped through the initial hoops, RTS,S will be tested in an implementation trial. This will involve making it available to 360 000 children: first in Malawi, and later in Kenya and Ghana. Malaria is endemic throughout <a href="https://dhsprogram.com/pubs/pdf/MIS18/MIS18.pdf">Malawi</a>, <a href="http://www.ghanahealthservice.org/ghs-subcategory.php?cid=4&scid=41">Ghana</a> and parts of <a href="https://www.who.int/news-room/feature-stories/detail/in-kenya-the-path-to-elimination-of-malaria-is-lined-with-good-preventions">Kenya</a>. </p>
<p>This next phase of the trial process will be used to further monitor the efficacy – as well as any potential adverse effects – of the vaccine in the context of routine use within national immunisation programmes.</p>
<p>Normally after the third phase of a clinical trial, one could consider licensing it if the results were good. In the case of this product, the results weren’t conclusively positive enough to proceed to licensing just yet. There was a lot of <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)00807-7/fulltext">debate</a> in the scientific community about whether it should be licensed or not. </p>
<p>This next phase of the trial process (implementation) will be used to further monitor the efficacy – as well as any potential adverse effects – of the vaccine in the context of routine use within national immunisation programmes. </p>
<p>It’s important to point out that there’s been a long process before this. RTS,S has been put through clinical trials – which usually consist of three phases. </p>
<p>Those trials showed that the vaccine only had <a href="https://www.ncbi.nlm.nih.gov/pubmed/25913272">modest efficacy</a>: it protected on average four of every 10 children who had been vaccinated. The trial also showed that this level of efficacy <a href="https://www.ncbi.nlm.nih.gov/pubmed/25072396">waned rapidly</a> and was practically undetectable 18 months after the last immunisation. </p>
<p>There were also potentially concerning adverse outcomes that need to be monitored further. These included a higher rate of <a href="https://www.ncbi.nlm.nih.gov/pubmed/25913272">meningitis</a> and a<a href="https://mbio.asm.org/content/7/2/e00514-16"> higher mortality</a> rate in girls. It’s important to point out that these were not necessarily caused by the vaccine, so more investigation will be needed to understand this issue.</p>
<p>Nevertheless, given the high burden of malaria in sub-Saharan Africa, a partially effective vaccine is considered better than none, and it is better to save some lives, than none at all.</p>
<p><strong>What happens next?</strong></p>
<p>Scientists now keenly await the results of the trials in Malawi, Ghana and Kenya. This is expected to give results within three to five years.</p>
<p>While we wait, the scientific effort to develop a more effective vaccine will continue as vigorously as ever. Researchers like myself are energised by the limited success of the current vaccine and are convinced that we can do better.</p>
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Read more:
<a href="https://theconversation.com/novel-approach-brings-african-scientists-closer-to-a-malaria-vaccine-106276">Novel approach brings African scientists closer to a malaria vaccine</a>
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<p><strong>So where are we in terms of finding a malaria vaccine?</strong></p>
<p>The development of vaccines against malaria is complex and challenging. The parasite responsible for the most severe disease complications in humans, <em>Plasmodium falciparum</em>, infects mosquitoes and humans and has distinct life-cycle stages in each of these hosts. It has evolved over millions of years to employ a myriad of strategies that enable it to evade destruction by the host immune system.</p>
<p>The parasite contains over 5000 proteins and displays variable proportions of these proteins to the immune system at different times. And the genes encoding these proteins can be cleverly switched on and off, or mutate in the course of an infection. It’s an ever-changing coat of many colours.</p>
<p>Scientists are tackling this problem from every possible angle.</p><img src="https://counter.theconversation.com/content/116007/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Faith Osier receives funding from the Wellcome Trust, the MRC/DFID African Research Leader Award, the European and Developing Countries Clinical Trials Partnership (EDCTP), the Sofja Kovalevskaja Award from the Alexander von Humboldt Foundation and TIBA - Tackling Infections to Benefit Africa. She is Vice-President/President-elect of the International Union of Immunological Societies.</span></em></p>
Given the high burden of malaria in sub-Saharan Africa, a partially effective vaccine is considered better than none.
Faith Osier, Immunologist , Wellcome Trust Sanger Institute
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/105553
2018-11-15T11:46:16Z
2018-11-15T11:46:16Z
A vaccine that could block mosquitoes from transmitting malaria
<figure><img src="https://images.theconversation.com/files/242751/original/file-20181029-76384-1torm2j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">High magnification view of mosquito pupae and larvae underwater.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-mosquito-pupae-larvae-underwater-134180195?src=FIzxvIwFKsqKs5Wq0P2SbQ-1-51">7th Son Studio/shutterstock</a></span></figcaption></figure><p>Is it possible to eradicate malaria? </p>
<p>It is a question with which many researchers have grappled, and many ideas have been proposed. The reason malaria has garnered so much attention is that it is one of the deadliest diseases, infecting 200 million people and killing <a href="https://www.cdc.gov/parasites/malaria/index.html">more than 500,000 annually</a>, with infants in Africa suffering the majority of fatalities. </p>
<p>The disease is a huge burden for humanity, damaging economies and social development. <a href="https://www.cdc.gov/parasites/malaria/index.html">According to the Centers for Disease Control and Prevention</a>, malaria treatments cost Africa nearly US$12 billion per year. Reports have shown that nearly <a href="https://www.cdc.gov/parasites/malaria/index.html">1,700 cases</a> are diagnosed annually in the United States, usually in people who have recently traveled to regions of Asia and Africa where the disease is endemic. </p>
<p>For some decades, researchers have being working on a novel idea called a “transmission-blocking vaccine.” This vaccine is different from traditional vaccines that protect the recipient from getting the disease. Here, the vaccine blocks the transmission of the parasite that causes malaria from an infected human host to mosquitoes. </p>
<p>When a human receives such a vaccine, specific antibodies are generated in the blood. When a mosquito bites and ingests the blood of an infected human, both the parasite and antibody are taken up into the mosquito’s stomach. Once inside the mosquito, the antibody attaches to the parasite and inhibits its development. This prevents the mosquito from transmitting the disease to another person.</p>
<p>The concept is bold but has not yet been tested in large-scale trials. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/243740/original/file-20181103-83626-1g5m9ao.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">How the transmission blocking vaccine works. The cycle of disease begins when a mosquito carrying the malaria parasite bites the first individual, infecting him with the disease. The paracite then replicates in the liver and spreads into the blood. When the vaccine is injected into the infected person, it stimulates the body to produce antibodies that then attach to the new parasites. When another mosquito feeds on the infected individual, it slurps up the malaria parasite and the antibody. The antibody prevents the immature parasite from developing, which means that this mosquito is unable to transmit the disease.</span>
<span class="attribution"><span class="source">Wei-Chiao Huang</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Liposomes: A vaccine carrier</h2>
<p>A vaccine works by showing the body a piece of the disease-causing microbe. The part itself doesn’t cause disease but gives the body a preview of the invader so that it can prepare antibodies that will tag the microbe and label it for destruction. </p>
<p>To develop a potent vaccine that induces a strong antibody response, the choice of protein from the disease-causing organism is critical. Scientists home in on particular proteins that the microbes produce to spike the vaccine. For our work, we chose a well-studied protein called Pfs25, which is found on the surface of the malaria parasite. </p>
<p>The parasite displays this protein on its surface when it is developing in the midgut of the mosquito. Pfs25 as target protein for transmission-blocking vaccine has been clinically <a href="https://clinicaltrials.gov/ct2/show/NCT02013687">tested</a> <a href="https://clinicaltrials.gov/ct2/show/NCT02532049">in</a> <a href="https://clinicaltrials.gov/ct2/show/NCT01867463">Phase</a> <a href="https://www.clinicaltrials.gov/ct2/show/NCT02334462">I</a> <a href="https://clinicaltrials.gov/ct2/show/NCT02942277">trials</a>; however, progress has been limited. That’s because, by itself, the Pfs25 protein triggers only weak production of specific antibodies. </p>
<p>In other approaches, researchers have taken steps to genetically engineer a modified and more potent Pfs25 for <a href="https://clinicaltrials.gov/ct2/show/NCT02013687">other</a> <a href="https://clinicaltrials.gov/ct2/show/results/NCT02532049?view=results">clinical</a> trials. In general, such approaches are promising, but there is some potential risk that the target protein does not exactly mimic the natural protein on the parasite.</p>
<p>We believe that a new type of vaccine that incorporates liposomes may be a promising candidate for a transmission-blocking vaccine adjuvant. An adjuvant is another vaccine component that potentiates the immune response. Liposomes are hollow spheres made from fat molecules.</p>
<p>The advantage of the liposomes, compared to just the Pfs25 protein alone, is that they can help deliver more parasite protein to immune cells. These cells uptake the liposomal vaccines and trigger the production of more antibodies which then target the parasite for destruction and block the disease.</p>
<p><a href="https://www.acsu.buffalo.edu/%7Ejflovell/people.html">Jonathan Lovell’s</a> team has developed a liposome as a vaccine to fight against malaria. In 2015, Dr. Lovell’s team figured out how to anchor proteins to the liposome by attaching them <a href="https://doi.org/10.1038/nchem.2236">to a string of amino acids called a histidine tag</a>. The tag works like an anchor which attaches the protein to the liposome. </p>
<p>Adding a cobalt-containing molecule, with a structure similar to vitamin B12, made the liposome-protein structure stable. </p>
<h2>Eliminating the spread of malaria</h2>
<p><a href="https://doi.org/10.1038/s41565-018-0271-3">The Lovell lab developed</a> a cobalt-laced liposome-based vaccine that displays the parasite proteins on its surface. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=221&fit=crop&dpr=1 600w, https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=221&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=221&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=277&fit=crop&dpr=1 754w, https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=277&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/243731/original/file-20181102-83635-1rcyw17.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=277&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Making a liposome vaccine: The Pfs25 protein is tethered to a histidine tag (green) and mixed together with a cobalt-containing liposome. The two parts combine to make a vaccine that is injected into the mouse. The insert shows how the histidine tail interacts with the liposome to keep the proteins firmly attached.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Making this vaccine is simple. Once we have the cobalt liposomes and the Pfs25-histidine molecules, we simply mix these parts together, and the structures form spontaneously. When this Pfs25 liposome is injected into mice, it triggers high quantities of antibodies. </p>
<p>The antibodies in the mice blocked development of parasites in the gut of the mosquito. So we expect that when an uninfected mosquito bites a person infected with the malaria parasite, the blood it sucks up will carry the parasite and the human antibodies that will prevent the parasite from multiplying in the insect’s gut. </p>
<p>When we tested this vaccine in mice, the animals continued to produce antibodies for more than 250 days. These antibodies produced throughout this period prevented the development of the malaria parasite throughout this period. </p>
<h2>Moving forward</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=294&fit=crop&dpr=1 600w, https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=294&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=294&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=369&fit=crop&dpr=1 754w, https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=369&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/242747/original/file-20181029-76399-1tylcyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=369&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Malaria disease around the world, 2014. Warning map for travelers with high risk of contracting malaria.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/malaria-disease-around-world-2014-warning-235538464">Peteri / Shutterstock.com</a></span>
</figcaption>
</figure>
<p>Another valuable feature of the cobalt liposome is that we can attach a variety of proteins from different stages of parasite development to create a particle that triggers the production of many types of antibodies – each targeting a unique part of the parasite. <a href="https://doi.org/10.1038/s41565-018-0271-3">Our results showed</a> that five distinct malaria proteins could be attached to the liposome surface. </p>
<p>The antibodies from mice immunized with liposomes carrying multiple proteins recognized many stages of parasite development. The results seem promising. In the future we plan to explore the safety of this vaccine and whether it will work for different species of malaria. </p>
<p>Our next step is to test our vaccine in other animals. Eventually the aim is to translate this technology to human clinical trials and assess whether the liposome technology and the transmission blocking vaccine strategy is an effective tool for preventing the spread of malaria.</p><img src="https://counter.theconversation.com/content/105553/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wei-Chiao Huang receives funding from PATH Malaria Vaccine Initiative (MVI) . </span></em></p><p class="fine-print"><em><span>Jonathan Lovell's lab has received funding from the NIH and PATH's Malaria Vaccine Initiative for this project. He also has an interest in POP Biotechnologies.</span></em></p>
Researchers have tried unsuccessfully for decades to develop a malaria vaccine. Now a new approach, showing promise in mice, suggests it is possible to block mosquitoes from spreading the disease.
Wei-Chiao Huang, Ph.D. Candidate in the Biomedical Engineering Department, University at Buffalo
Jonathan Lovell, Associate Professor of Biomedical Engineering, University at Buffalo
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/106276
2018-11-07T13:10:37Z
2018-11-07T13:10:37Z
Novel approach brings African scientists closer to a malaria vaccine
<figure><img src="https://images.theconversation.com/files/244103/original/file-20181106-74783-r02f38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists analysing data at the South-South Malaria Research Partnership project laboratory in Kenya. </span> <span class="attribution"><span class="source">Flora Mutere-Okuku</span></span></figcaption></figure><p>Malaria is still a major problem in Africa. There are over <a href="http://www.who.int/malaria/publications/world-malaria-report-2017/en/">200 million clinical cases</a> each year and approximately half a million deaths. </p>
<p>There are different ways in which malaria can be controlled. Preventive measures include use of insecticides in bed nets or indoor spraying programmes. Medicines can also be used to prevent or treat malaria, but resistance often develops and drugs lose their effectiveness. </p>
<p>The World Health Organisation <a href="http://www.who.int/en/news-room/detail/29-11-2017-global-response-to-malaria-at-crossroads">reported</a> that progress in controlling malaria has stalled. </p>
<p>As an immunologist, I dream that one day we will have an effective vaccine that will help eliminate malaria. I think this is possible because for over a century, we have known that humans do become immune to malaria. In places where there is lots of malaria adults don’t succumb to the disease, but their young children do. </p>
<p>In experiments conducted over 50 years ago, researchers showed that blood could be taken from <a href="https://www.nature.com/articles/192733a0">adults who had become immune</a> and used to treat children admitted to hospital with malaria. </p>
<p>Antibodies in the blood were responsible for this effect; in other words, antibodies could treat malaria. Researchers have been trying to isolate the exact antibodies that do this. The challenge is that our bodies make millions of antibodies, so pulling out those with the antimalarial activity has been difficult.</p>
<p>One way to identify these “good” antibodies is to compare the blood samples of people who get malaria with those who don’t with the aim of identifying the differences. This type of research has been going on for about 30 years, but the results have been <a href="https://www.ncbi.nlm.nih.gov/pubmed/20098724">inconclusive</a>. </p>
<p>Part of the reason is that in almost every study, the investigators do things differently. </p>
<p>It’s like cooking your favourite dish. You may have a particular recipe but if you check in with friends and ask how they prepare the very same dish, you will find that each of them does something slightly differently. In the same way, differences in the way scientists have conducted their experiments have contributed to a lack of clarity in the results. </p>
<p>We’ve embarked on a project that breaks this cycle. </p>
<h2>The project</h2>
<p>In experiments conducted over 50 years ago, researchers showed that blood could be taken from <a href="https://www.nature.com/articles/192733a0">adults who had become immune</a> and used to treat children admitted to hospital with malaria. </p>
<p>We used the latest technology to analyse our samples. We designed a small glass slide on which we stuck over 100 carefully selected proteins from the malaria parasite. With less than a drop of blood, we were able to simultaneously <a href="https://www.smartpartnership.net/science">measure antibodies</a> to all these proteins. </p>
<p>This was a major step-change. When I started this research 14 years ago, I used to measure antibodies to one parasite protein at a time, using a lot more blood, and in samples from one area in Kenya. </p>
<p>Developments in technology now mean that it’s possible to do this much more efficiently. And we’re really excited that we have been able to exploit these new innovations in Africa. </p>
<p>My team analysed antibodies in over 10,000 samples in three months. We are now working through the statistical analysis of this data to understand how people who are immune to malaria do it.</p>
<p>My team is also working on understanding how antibodies <a href="https://www.ncbi.nlm.nih.gov/pubmed/27546781">kill malaria</a> parasites. It’s still unclear if the antibodies attack the parasite from different angles or whether different antibodies are synergistic in their actions. </p>
<p>We also don’t know how much antibody is necessary. </p>
<h2>What we know</h2>
<p>So far, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2346713/">our studies</a> suggest that having a bit of one antibody is not good enough, and we may need high concentrations of antibodies against combinations of parasite proteins. </p>
<p>We are also <a href="https://www.ncbi.nlm.nih.gov/pubmed/26787721">learning</a> that antibodies kill parasites in many ways, and that studying any one of these in isolation may not adequately reflect reality. </p>
<p>I believe the key to making a better malaria vaccine is right here with us. With patience, perseverance and continued hard work, we will find the recipe required to make a really good malaria vaccine.</p><img src="https://counter.theconversation.com/content/106276/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Faith Osier receives funding from the Wellcome Trust, the MRC/DFID African Research Leader Award, the European and Developing Countries Clinical Trials Partnership (EDCTP), the Sofja Kovalevskaja Award from the Alexander von Humboldt Foundation and TIBA - Tackling Infections to Benefit Africa. She is Vice-President/President-elect of the International Union of Immunological Societies. </span></em></p>
Progress in malaria control has stalled. Research towards an effective vaccine is underway.
Faith Osier, Immunologist , Wellcome Trust Sanger Institute
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/95101
2018-04-22T09:51:18Z
2018-04-22T09:51:18Z
Why Kenya isn’t winning the war against malaria in some counties
<figure><img src="https://images.theconversation.com/files/215752/original/file-20180420-75114-879d0s.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">Shutterstock</span></span></figcaption></figure><p>In the past 15 years the Kenyan government has made great strides in preventing and controlling malaria. It has issued insecticide treated bed nets, sprayed people’s homes with insecticides and ensured that there is widespread diagnostic testing. These efforts have resulted in a <a href="http://www.who.int/features/2017/vector-control-kenya/en/">significant drop</a> in transmission rates. </p>
<p>But progress has not been uniform. Parts of Kenya – particularly the counties in the west of the country along the Rift Valley – are still plagued by serious seasonal cases of the deadly disease. </p>
<p>Seasonal outbreaks of malaria in these counties are most common in the wet season which runs from March to June and then again from October to December. But in years with high rainfall it also rains in January and February, which was the case this year. As a result, in February this year, for example, the arid counties of Baringo, West Pokot and Marsabit saw an outbreak where hundreds of people were <a href="https://www.standardmedia.co.ke/article/2001269063/another-malaria-outbreak-hits-baringo-county">hospitalised</a>. Most of the patients were children under the age of five – a group that’s globally considered a <a href="http://apps.who.int/iris/bitstream/10665/200018/1/9789241565158_eng.pdf?ua=1#page=47">high risk for severe malaria</a>. </p>
<p>The outbreak follows a similar one in October last year where in less than a weak more than 400 people were hospitalised and at least <a href="https://www.the-star.co.ke/news/2017/10/03/10-dead-400-admitted-after-malaria-outbreak-in-baringo-west-pokot_c1646017">10 had died</a> from malaria.</p>
<p>In Baringo county, malaria is of particular concern – accounting for 11.8% of the <a href="http://www.humanitarianresponse.info/system/files/">outpatient cases recorded</a>. This is higher than the nationwide malaria prevalence of 8%.</p>
<p>So what’s preventing <a href="http://www.e-kconsulting.co.ke/Resources%20/kenya-malaria-indicator-survey-report-2015-kmis-2015">Baringo county and other areas</a> from reducing its malaria caseload like other parts of the country? </p>
<p>A number of factors are at play. These include weak health systems, which are a common feature of the counties in the arid and semi arid areas of the country. In these areas the health facilities are sparsely distributed, have poor equipment and are understaffed. The areas also have poor road networks. On top of this, these areas are affected by conflict which in turn gets in the way of the government providing decent healthcare. </p>
<p>And finally, the environment also poses a challenge because they increase the number of larval breeding sites for the mosquitoes in the wet months, which increases the outbreaks of malaria. </p>
<h2>County challenges</h2>
<p>Health facilities in the arid and semi arid counties of Kenya are <a href="http://www.baringo.go.ke/index.php?option=com_content&view=article&id=1580:proposed-health-projects-for-the-financial-year-2016-2017&catid=10&Itemid=188">sparsely distributed</a>. On average most patients in remote villages need to walk more than 15 kilometres to the nearest facility. The facilities are also understaffed with inadequate medical equipment and insufficient anti-malarial drugs. </p>
<p>On top of this, criminal gangs have taken control in many areas in the wake of the ongoing conflict between two communities – the Pokot and Marakwet. As a result nurses regularly <a href="https://www.standardmedia.co.ke/article/2001269063/another-malaria-outbreak-hits-baringo-county">flee medical facilities</a> leaving no one in charge.</p>
<p>The fact that herding is the main economic activity in Baringo has also been a contributory factor to the higher rates of malaria. Research into the breeding habits of one of the mosquitoes that spreads malaria in the region – the <em>Anopheles arabiensis</em> – shows that it feeds on humans as well as livestock. Therefore, high livestock densities in an area where herders converge in communal grazing lands translate into more people being <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3120729/">bitten</a>. </p>
<p>The seasons also play a role. In the dry season, the vector is sustained by permanent habitats like swamps and drainage canals from these swamps <a href="https://www.ncbi.nlm.nih.gov/pubmed/21352608">malaria vectors</a>. </p>
<p>During the <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=Plasmodium+falciparum+transmission+and+aridity%3A+a+Kenyan+experience+from+the+dry+lands+of+Baringo+and+its+implications+for+Anopheles+arabiensis+control">rainy season</a>, the breeding sites increase when seasonal rivers and manmade habitats such as pan dams, concrete tanks, ditches and trenches get filled up with water. This increases the number of vectors and hence the outbreaks.</p>
<p>Living conditions are also a challenge. Most of the houses have thatched roofs and don’t have adequate screening on the doors and windows. This means that mosquitoes can easily enter.</p>
<h2>A few solutions</h2>
<p>The challenges in Baringo can be tackled in a few ways. But these require the resources of Kenya’s national and county governments. </p>
<p>Firstly, the national government needs to improve security so that medical staff aren’t forced to flee for their safety. </p>
<p>Secondly, the county governments need to come to the party too:</p>
<ul>
<li><p>provide adequate supplies of anti-malarials as well as enough diagnostic facilities and equipment</p></li>
<li><p>increase their distribution of insecticide-treated bednets as only 52% of the population living in malaria risk zones has been covered. </p></li>
<li><p>improve the way they manage their environments and introduce targeted larval control. This includes filling up the unnecessary ditches and trenches, draining stagnant water and applying larvicides into the irrigation canals to reduce the vector population. The highly localised nature of breeding sites in these semi-desert environments provides a good opportunity. </p></li>
<li><p>improve public health education and awareness. Pregnant women should be told of the benefits of taking antimalarial drugs during pregnancy and other residents should be encouraged to sleep under insecticide treated nets and to avoid unnecessary exposure to mosquito bites. </p></li>
</ul>
<p>There are other, more radical steps, county governments could take. Because house types have become an important <a href="https://www.ncbi.nlm.nih.gov/pubmed/21352608">factor in malaria transmission</a> they could consider encouraging people to shift from mud grass thatched huts to concrete houses with sealable windows. </p>
<p>They could also consider deploying mobile clinics and investing in ambulances to ferry patients from far-flung parts of the counties. </p>
<h2>A malaria-free Kenya</h2>
<p>Kenya is one of the three countries in Africa selected for the trials of a <a href="https://www.businessdailyafrica.com/news/Kenya-picked-for-key-global-anti-malaria-vaccine-trial/539546-3902510-9wfahcz/index.html">malaria vaccine</a> administered to infants who are five-months-old. </p>
<p>If the vaccine does prove effective during these trials it could become part of the core package of World Health Organisation recommended interventions and could provide a solution for residents in seasonal transmission zones. </p>
<p>It is clear that Kenya has made substantial progress towards eliminating malaria and other communicable diseases. If the Ministry of Health remains committed to further reducing the malaria burden in coming years, a malaria-free Kenya is possible.</p><img src="https://counter.theconversation.com/content/95101/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eunice Anyango Owino works for the University of Nairobi as a lecturer and consults with the International Centre of Insect Physiology and Ecology. She receives funds from the National Commission for Science Technology and Innovation (NACOSTI) and the International foundation for Sciences (IFS). </span></em></p>
Baringo county and other areas on the western side of Kenya are struggling to reduce their seasonal malaria caseloads.
Eunice Anyango Owino, Medical Entomologist at the School of Biological Sciences, University of Nairobi
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/88577
2017-12-10T11:24:34Z
2017-12-10T11:24:34Z
Global malaria report reveals Africa’s hits and misses: here’s what to do
<figure><img src="https://images.theconversation.com/files/197571/original/file-20171204-4062-tnv2cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most malaria cases and deaths occur in sub-Saharan Africa. </span> <span class="attribution"><span class="source">Susana Vera/Reuters</span></span></figcaption></figure><p>The <a href="http://www.who.int/malaria/publications/world-malaria-report-2017/report/en/">2017 World Malaria Report</a> provides a clear picture of the work required to control malaria. Data from over 90 countries reveals a dramatic reduction in the rates of disease and deaths between 2010 to 2015. But malaria deaths remained unchanged in Africa from 2015 to 2016.</p>
<p>During the same time period, the number of malaria deaths stalled in South-East Asia and Western Pacific while increasing in the Eastern Mediterranean and the Americas.</p>
<p>There is no magic bullet yet for malaria control. But it appears that even the most familiar prevention strategies are not being fully utilised. For example, under trial conditions, insecticide treated bednets convincingly demonstrated a <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD000363/abstract">cut in malaria by half</a>. Yet this year’s report indicates that coverage of bednets is about 54%. This means that nearly half of the people who should be sleeping under the nets are not. The main drawback is funding to supply bednets and deliver them where they are needed most.</p>
<p>On top of that, <a href="https://wwwnc.cdc.gov/eid/article/20/10/14-0619_article">resistance to the only insecticide</a> currently used for treating bednets has been reported in <a href="http://apps.who.int/iris/bitstream/10665/259492/1/9789241565523-eng.pdf?ua=1%20**is%20it%20strange%20to%20have%20a%20link%20the%20world%20malaria%20report%20again%20here%20or%20is%20it%20ok?**">over two thirds of African sites</a> that have been monitored. There is a gap both in coverage of bednets and in research of new insecticides.</p>
<p>Although the 2017 World Malaria Report shows a plateau of the impact of malaria prevention and control strategies, this is not because they have reached their full potential. Far from it. The current interventions are hardly enough to eradicate malaria but if fully put to use, thousands of lives would be saved. </p>
<p>If the rate of decline of malaria disease and death has plateaued, we should not pretend that things will get better from this point. As <a href="http://who.int/malaria/publications/world-malaria-report-2017/WMR-2017-foreword-eng.pdf">Dr Tedros Adhanom Ghebreyesus, WHO secretary general says</a>:</p>
<blockquote>
<p>The choice before us is clear. If we continue with a “business as usual” approach – employing the same level of resources and the same interventions – we will face near-certain increases in malaria cases and death.</p>
</blockquote>
<p>New interventions are needed to suit a variety of malaria transmission patterns. New ways of utilising old methods have also been shown to work.</p>
<h2>New strategies needed</h2>
<p>Giving anti-malarials to healthy people to prevent malaria disease and death is not a new thing and <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD000169.pub2/full">is used routinely in pregnant women</a> , <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003756.pub3/full">pre-school children </a>,<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647321/">school children</a> and <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008846.pub2/full">whole communities</a> in malaria endemic areas. Despite the evidence available on the utility of this approach, it has been rolled out consistently as routine policy among pregnant women only. </p>
<p>However, in the Sahel region, which includes countries whose northern border is the Sahara desert like Burkina Faso, Cameroon, Chad, Gambia, Ghana, Guinea, Guinea-Bissau, Mali, Niger, Nigeria, Senegal and Togo, the malaria season is brief and intense. Almost all malaria disease and death occurs within the three to four month rainy season and <a href="https://www.msf-me.org/article/malaria-msf-provides-preventive-treatment-to-children-in-the-sahel-region">over 20 million children</a> are at risk.</p>
<p>Studies done in the 2000s to determine whether the monthly use of anti-malarials during the rainy season among children six months to five years reduced malaria cases showed that it <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003756.pub4/abstract">reduced malaria disease by 75%</a>. </p>
<p>Using the evidence from this review, in 2012 the WHO made a <a href="http://www.who.int/malaria/publications/atoz/who_smc_policy_recommendation/en/">recommendation</a> that the seasonal intervention with sulphadoxine pyrimethamine and amodiaquine should be given at monthly intervals for three to four months in parts of sub Saharan Africa with highly seasonal malaria and where the parasite is sensitive to these drugs.</p>
<p>However, the 2017 World Malaria Report shows that over 13 million children who could have benefited from seasonal treatment with anti-malarials in 2016, were not covered due to lack of funding.</p>
<h2>Exploring new fronts</h2>
<p>Building on this strategy, malaria expert <a href="https://royalsociety.org/people/brian-greenwood-11537/">Professor Brian Greenwood</a> has suggested that <a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-017-1841-9">the use of a partially effective malaria vaccine</a>, RTS,S/AS01, during the malaria season may also be useful in the Sahel region. </p>
<p>But rolling out the malaria vaccine will not be as straight forward as giving children medicine to swallow. The <a href="https://www.ncbi.nlm.nih.gov/pubmed/22940378">vaccine requires refrigeration</a> and the children will need to receive multiple injections to attain efficacy. The potential of seasonal vaccination would be worth the difficulties if new malaria vaccines with better efficacy would be developed. </p>
<h2>A promising future</h2>
<p>In the meantime, there are simpler ways to improve the delivery of seasonal anti-malarials to children. In a <a href="https://malariajournal.biomedcentral.com/articles/10.1186/s12936-017-1974-x">recently published study from Mali</a>, the health workers had to crush the tablets in water and add sugar to make it more palatable. How much better it would be if there was a sugar-free flavoured solution for children? Considering the millions of doses of the drug needed, a developing world pharmaceutical company should consider making a more edible version of the medicine. </p>
<p>Finally, all is not lost because African countries such as <a href="http://apps.who.int/iris/bitstream/10665/205565/1/WHO_HTM_GMP_2016.3_eng.pdf">Egypt and Morocco have been malaria free since 2000</a>. According to the WHO to attain this status requires a country to demonstrate that there have been no indigenous malaria cases reported for three years in a row. Algeria achieved this feat in 2016 and another five African countries: Botswana, Cape Verde, Comoros, South Africa and Swaziland have been identified as most likely to eliminate malaria by 2020. </p>
<p>It is encouraging to watch malaria disappear in some parts of Africa, raising hope for the fight against malaria.</p><img src="https://counter.theconversation.com/content/88577/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tabitha Mwangi 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>
After an exceptional period of success in global malaria control, the progress has stalled. New strategies are needed to suit a variety of transmission patterns.
Tabitha Mwangi, Senior Lecturer, Anglia Ruskin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/80281
2017-07-18T14:44:40Z
2017-07-18T14:44:40Z
A new vaccine is promising to advance the frontier of eliminating malaria
<figure><img src="https://images.theconversation.com/files/176381/original/file-20170630-8190-11ktn0z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A malaria vaccine will be piloted in Ghana, Kenya and Malawi to assess its suitability.</span> <span class="attribution"><span class="source">Siegfried Modola/Reuters.</span></span></figcaption></figure><p>More than <a href="http://www.who.int/immunization/policy/position_papers/malaria_pp_jan2016_summary.pdf">30 malaria vaccine</a> candidates are at various stages of development. The <a href="http://www.malariavaccine.org/malaria-and-vaccines/first-generation-vaccine/rtss">RTS,S</a> vaccine is at the most advanced stage.</p>
<p>The World Health Organisation has <a href="http://www.un.org/sustainabledevelopment/blog/2017/04/ghana-kenya-and-malawi-to-pilot-malaria-vaccine-trial-un/">recommended</a> the introduction of the vaccine in Ghana, Kenya and Malawi as a pilot programme to assess its suitability in expanded immunisation programmes.</p>
<p>The vaccine could prove to be a powerful tool in sustaining the gains made in the last decade in reducing malaria related cases and deaths. Between 2000 and 2015, new malaria cases <a href="http://www.who.int/malaria/media/world-malaria-report-2015/en/">fell</a> by 37% globally, and by 42% in Africa. This has been achieved through key interventions such as using treated bed nets, spraying houses with insecticides and effective antimalarial drugs. </p>
<p>Combined with existing malaria interventions, the vaccine would have the potential to save tens of thousands of lives in Africa. It’s important for two other reasons too. </p>
<p>Firstly, it would reduce the cost of managing malaria. Historically, vaccines are more <a href="https://www.ncbi.nlm.nih.gov/pubmed/23142307">cost-effective</a> in <a href="http://www.who.int/heli/risks/vectors/malariacontrol/en/">preventing</a> the spread of diseases compared to other methods.</p>
<p>Secondly, the vaccine could deal with <a href="http://www.who.int/malaria/areas/drug_resistance/overview/en/">resistance</a> to both drugs and insecticides that’s on the rise.</p>
<h2>The vaccine’s history</h2>
<p>The RTS,S malaria vaccine <a href="http://www.malariavaccine.org/sites/www.malariavaccine.org/files/content/page/files/RTSS%20vaccine%20candidate%20Factsheet_FINAL.pdf">was created</a> in 1987 by scientists working at GlaxoSmithKline laboratories. Early clinical development of the vaccine was conducted in collaboration with the Walter Reed Army Institute for Research.</p>
<p>In January 2001, GlaxoSmithKline and PATH’s Malaria Vaccine Initiative entered into a public-private partnership to develop RTS,S for infants and young children living in malaria-endemic regions of sub-Saharan Africa. </p>
<p>Phase I and II clinical trials allowed an initial assessment of the safety and efficacy of the vaccine, <a href="https://www.ncbi.nlm.nih.gov/pubmed/26919472">initially</a> in adult volunteers in the US and Belgium. </p>
<p>This was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829262/">followed by</a> adults, adolescents, children, and then infants living in malaria-endemic regions in Africa.</p>
<p>The results from the Phase II proof-of-concept trials in Mozambique, published in <a href="http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(13)70005-7/abstract">The Lancet </a>in 2004 and 2007, demonstrated that the vaccine provided partial protection against malaria to African children and infants. </p>
<p>This paved the way for a pivotal <a href="http://www.nejm.org/doi/pdf/10.1056/NEJMe1606007">Phase III</a> efficacy and safety trial in 15,459 infants and young children at 11 sites in seven African countries. These were Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique, and Tanzania. The trial started in May 2009 and ended in early 2014.</p>
<p>The <a href="http://www.malariavaccine.org/files/MVI-GSK-RTSSfactsheetFINAL-web.pdf">results</a> of the phase III trial were submitted to regulatory authorities and in July 2015 RTS,S received a <a href="https://www.malarianomore.org.uk/news/malaria-vaccine-approved-use-european-medicines-agency">positive scientific opinion</a> from the European Medicines Agency. </p>
<p>In January 2016, the WHO recommended introduction of RTS,S through a pilot implementation programme in 3 to 5 African countries. Its recommendation called for a four dose series of the vaccine. The first dose to be administered as close as possible to 5 months of age, followed by doses two and three at one month intervals and a fourth dose 15 to 18 months after dose three.</p>
<p>The pilot implementation, will evaluate:</p>
<ul>
<li><p>the operational feasibility of providing RTS,S at the recommended four-dose schedule, </p></li>
<li><p>the impact of the vaccine on malaria specific deaths, and </p></li>
<li><p>the safety of the vaccine.</p></li>
</ul>
<h2>Choosing the pilot</h2>
<p>Ghana, Kenya, and Malawi were selected based on a number of factors. They have high coverage of long-lasting insecticidal nets, well-functioning malaria and immunisation programmes, a high malaria burden and have taken part in an earlier phase of the vaccine trial. </p>
<p>Because malaria can vary from one region to another – even within a country – the three countries will decide on the districts and regions to be included in the pilots. High malaria burden areas will be prioritised. </p>
<p>The piloting of the malaria vaccine in these three countries is a major milestone in vaccine research as it will pave way for the next steps in making decisions about whether it will be widely deployed elsewhere. </p>
<p>If that happens, the vaccine has the potential to play a role in reducing the malaria burden. </p>
<p>The vaccine is meant to complement rather than replace existing proven malaria interventions. But there’s a growing threat of malaria parasites becoming resistant to antimalarial drugs and mosquitoes developing resistance to insecticides used in bednets and indoor residual spraying.</p>
<p>Once it’s licensed and becomes widely available, the vaccine will be a vital new intervention that can help mitigate these developments.</p>
<p>The pilot provides an opportunity to evaluate the vaccine in real-life situation. The next steps will involve regulatory authorities reviewing the results and making recommendations for wide deployment.</p>
<h2>Way forward</h2>
<p>The RTS,S vaccine is a first generation malaria vaccine. This means there’s still room to improve its capability to protect against malaria. But it won’t be the silver bullet which is why other studies into new drugs and interventions are important.</p>
<p>New prevention strategies – such as a new generation insecticide-treated nets that use a combination of insecticides to protect against mosquito resistance – are being explored. And single dose antimalarial drugs to ensure people complete the recommended dosage are also being explored.</p>
<p>Finally, the use of antimalarial drugs that target the sexual stages of the parasite are also being explored.</p><img src="https://counter.theconversation.com/content/80281/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Kariuki 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>
Stronger malaria prevention like a vaccine is urgently needed for effective response in endemic regions.
Simon Kariuki, Chief Research Officer, Malaria Branch Chief in the KEMRI, CDC and London School of Tropical Medicine Collaborative Program, Kenya Medical Research Institute
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/71760
2017-01-26T13:45:43Z
2017-01-26T13:45:43Z
New insights into the complex link between iron supplements and malaria
<figure><img src="https://images.theconversation.com/files/154239/original/image-20170125-23838-i2ftr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Public health campaigns in malaria prone areas should increase.</span> <span class="attribution"><span class="source">Stephen Morrison/EPA</span></span></figcaption></figure><p>Children under five years in Africa are at a higher risk of anaemia as well as being <a href="http://www.ajtmh.org/content/71/2_suppl/25.full">exposed to malaria</a> than children in other parts of the world. Most of this anaemia is due to <a href="http://www.webmd.com/a-to-z-guides/understanding-anemia-basics">iron deficiency</a>.</p>
<p>But treating children for anaemia by giving them iron supplements is fraught with problems. This is because it can lead to children becoming more susceptible to malaria. This is a controversial contention and studies looking at iron supplementation and malaria risk have produced <a href="https://www.ncbi.nlm.nih.gov/pubmed/27566983">conflicting results</a>. </p>
<p>But a new study done at the University of North Carolina’s School of Medicine <a href="https://www.sciencedaily.com/releases/2017/01/170105160212.htm">validates</a> observations about the effect of iron supplements on children’s susceptibility to malaria. It found that children with iron deficiency anaemia who were given iron supplements were at increased risk of malaria. But this effect is transient.</p>
<p>There are <a href="http://www.nhs.uk/Conditions/Anaemia-iron-deficiency-/Pages/Causes.aspx">different causes of anaemia</a>. Iron deficiency anaemia occurs when the body doesn’t have enough iron leading to a decreased number of red blood cells. </p>
<p>Iron supplements, the main treatment regime for iron deficient anaemia, leads to <a href="https://www.nhlbi.nih.gov/health/health-topics/topics/ida/treatment">renewed production</a> of red blood cells. Malaria parasites prefer younger red blood cells and so attack them. This increases malaria parasite multiplication and thus the risk of disease.</p>
<p>The results of the research underscore the fact that children should be offered preventative treatment against malaria if they are being given iron supplements.</p>
<h2>Iron supplementation trials</h2>
<p>These results provide an explanation to findings from a field study by Sunil Sazawal in Pemba Island, Tanzania, involving over 16,000 <a href="https://www.ncbi.nlm.nih.gov/pubmed/16413877">children</a>. The study compared malaria deaths among children with iron deficiency anaemia who were receiving iron supplements and those who weren’t. The study reported a 15% increase in deaths among those who received supplementation and was stopped early.</p>
<p>A number of studies have looked at iron supplementation and malaria risk. A highly respected <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006589.pub4/abstract;jsessionid=3AE771EE49EF3FA859A4ABE10B66F48E.f02t03">Cochrane review</a> published last year by Ami Neuberger and colleagues provided a comprehensive view of the issue after considering over 35 trials that involved 31,955 children. They concluded that in areas where malaria prevention and management are in place, iron supplementation does not affect occurrence of severe malaria disease or death. </p>
<p>Iron supplementation alongside malaria prevention resulted in a 50% drop in clinical malaria.</p>
<p>But in areas with no malaria prevention and management, as in the Sazawal study, iron supplementation may lead to a transient increase in malaria. </p>
<h2>Reducing the malaria burden</h2>
<p>The latest <a href="http://www.who.int/malaria/media/world-malaria-report-2016/en/">World Health Organisation data</a> shows that in 2015, there were about 212 million cases of malaria in the world. About 292,000 children under five years of age died from the disease in sub-Saharan Africa. </p>
<p>It’s estimated that in Kenya there are 6.7 million cases of malaria each year and about 4000 deaths. </p>
<p>But there has been progress. Between 2000 and 2015 cases of malaria in Africa dropped by 42% and mortality by 66%. Effective treatments and <a href="http://www.who.int/malaria/areas/high_risk_groups/children/en/">wider access</a> to treated bed nets are thought to be the main drivers of this reduction.</p>
<p>Better economic growth also plays a part. Wealthier countries are closer to <a href="http://www.scidev.net/global/malaria/news/global-wealth-primed-curb-malaria.html">eliminating malaria</a> than poorer countries.</p>
<p>There is no vaccine available although the RTS,S vaccine is close to being <a href="http://www.malariavaccine.org/malaria-and-vaccines/first-generation-vaccine/rtss">licensed</a>. The World Health Organisation expects it to be rolled out in some African countries <a href="http://www.who.int/immunization/research/development/malaria_vaccine_qa/en/">in 2018</a>.
In the meantime, the race continues for a more efficacious vaccine. Professor Adrian Hill and his team at the University of Oxford are working to improve on RTS,S. </p>
<p>There are likely to be quite a number of vaccine trials in the future and an improved RTS,S is just one of them.</p>
<h2>The way forward</h2>
<p>There is still a lot of work that is needed from the scientific world to bring malaria to its knees.</p>
<p>Researchers continue to gather data on trends in malaria as well as <a href="http://www.who.int/malaria/areas/vector_control/insecticide_resistance/en/">drug and insecticide resistance</a>. Malaria parasites and mosquitoes adapt quickly to whatever control measures are thrown at them so scientists must be <a href="https://www.fic.nih.gov/News/GlobalHealthMatters/january-february-2014/Pages/malaria-drug-resistance-mutation-niaid.aspx">a step ahead</a>.</p>
<p>Scientists continue to conduct research to improve on the insecticides used on bed nets and indoor house spraying. They also have to continue looking for new treatments to ensure that, should resistance to current anti malaria drugs emerge, the world is prepared.</p>
<p>On top of the efforts by scientists there must also be more effort put into awareness campaigns in malaria prone areas. When the RTS,S vaccine is rolled out, parents need to be reminded that the vaccine will not fully protect their children from malaria.</p>
<p>They need to ensure that children continue to sleep under insecticide treated bed nets and that malaria fevers are treated on time. If this is not done, progress in malaria control on the continent may be lost. </p>
<p>And special consideration must be given to the fact that preventative measures are particularly important if iron supplements are being given to children to treat anaemia.</p><img src="https://counter.theconversation.com/content/71760/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tabitha Mwangi 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 link between taking iron supplements and the increased risk of contracting malaria is a complex one.
Tabitha Mwangi, Senior Lecturer, Anglia Ruskin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/49873
2015-11-04T04:05:01Z
2015-11-04T04:05:01Z
Seven things worth knowing about mosquitoes
<figure><img src="https://images.theconversation.com/files/100535/original/image-20151102-16527-1dthulh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Anopheles Gambiae, one of three mosquitoes found in Africa that transmit malaria.</span> <span class="attribution"><span class="source">shutterstock</span></span></figcaption></figure><p><em><em>This article is part of a series The Conversation Africa is running as part of the South African Development Community malaria week. You can read the rest of the series <a href="https://theconversation.com/africa/topics/sadc-malaria-week">here</a>.</em></em></p>
<p><strong>1. Not all mosquitoes bite.</strong></p>
<p>The female mosquitoes are the dangerous ones. They bite and draw blood. Male mosquitoes feed on flower nectar. Males have very hairy and fuzzy antennae (like a powder puff) whereas females have less hairy antennae. </p>
<p><strong>2. There are three types of malaria carrying mosquitoes.</strong></p>
<p>The top three malaria transmitters in Africa are Anopheles gambiae, Anopheles funestus and Anopheles arabiensis. The first two live in areas of Africa where there is higher rainfall while the third, Anopheles arabiensis, is a more savanna-based, arid zone species. </p>
<p>Gambiae and funestus prefer to feed indoors and are strongly attracted to humans, but arabiensis feeds as easily outdoors as indoors and also as easily on cattle and other animals as humans. This means it is easier to target gambiae and funestus using indoor methods such as spraying walls with insecticides and using insecticide-impregnated bed nets. The outdoor-feeding arabiensis is far more difficult to control. </p>
<p>In most areas all three species have a peak of biting in the early hours of the morning when people are in their deepest sleep and less likely to disturb mosquitoes during the feeding process. There are also other important species of malaria-transmitting mosquitoes but they are more localised in distribution.</p>
<p><strong>3. Mosquitoes have started to change their feeding patterns.</strong></p>
<p>Because of the strong focus on indoor strategies to fight malaria transmitting mosquitoes using bed nets and indoor spraying, genetic selection is resulting in some populations of these mosquitoes biting outdoors and earlier at night when people are not protected by bed nets. It means these mosquitoes are more difficult to reach with insecticides, just as is the case with Anopheles arabiensis.</p>
<p><strong>4. Most mosquito bites are harmless. It’s only the ones that carry certain types of parasites that lead to malaria, and potentially death.</strong></p>
<p>In Africa, there are four known species of microscopically small parasites that can cause the disease we call malaria. All four belong to the group <em>Plasmodium</em>. The most common of these parasites in Africa is <em>Plasmodium falciparum</em>, which is the most deadly of the four species. </p>
<p>Birds and some other groups of animals carry their own species of <em>Plasmodium</em>, which is also transmitted by mosquitoes, but they do not cause malaria in humans. Mosquitoes also carry many other disease-causing organisms such as yellow fever virus, West Nile virus, Rift Valley fever, and the worms that cause the dreaded disfiguring elephantiasis (filariasis).</p>
<p><strong>5. Mosquitoes select where they feed on the body. They have very acute sensory mechanisms (like heat-seeking missiles) that lead them to select particular parts of the body (such as ankles) to feed from.</strong></p>
<p>All three of the main malaria carrying mosquitoes have similar biting preferences. If you are sitting or standing outside in the evening the overwhelming majority will try to feed on your ankles and feet - so make sure you cover these areas with repellent or wear socks and shoes.</p>
<p>The antennae of mosquitoes are highly specialised sensory organs that can detect very small amounts of chemical cues that lead them to food and mates. Various chemicals, of which carbon dioxide is one, help female mosquitoes track down their hosts. Pheromones, which are hormones secreted as odours into the environment, enable males and females to meet and mate. They are also detected by the antennae.</p>
<p><strong>6. Malaria mosquitoes do not like wind.</strong></p>
<p>Using a fan over you when going to bed will lessen your chances of being bitten. These mosquitoes don’t like flying when there is even a slight breeze.</p>
<p><strong>7. 97 countries and territories still face ongoing malaria transmission.</strong></p>
<p>According to the World Health Organisation, an estimated 3.2 billion people, or just under half the world’s population, are at risk of getting malaria. The bulk of the malaria burden is shouldered by Africa where 89% of cases and 91% of deaths occur.</p><img src="https://counter.theconversation.com/content/49873/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Professor Leo Braack received funding from Bill & Melinda Gates Foundation and also University of Pretoria to conduct malaria research</span></em></p>
The irritating buzz that rings in your ear in the dead of the night comes from an insect barely traceable with your naked eye. Here are a few facts worth knowing about the mosquito.
Leo Braack, Research Chair, Integrated Vector Management in the Vector Control Cluster, Centre for Sustainable Malaria Control , University of Pretoria
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/49986
2015-11-03T04:06:11Z
2015-11-03T04:06:11Z
The quest to find a drug that nails the tricky malaria parasite
<figure><img src="https://images.theconversation.com/files/100525/original/image-20151102-16554-rjrqi5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A doctor observes mosquitoes to better understand the malaria parasite which has been developing a resistance to the anti-malarial drugs.</span> <span class="attribution"><span class="source">Reuters/RIcardo Rojas</span></span></figcaption></figure><p><em><em>This article is part of a series The Conversation Africa is running during malaria week in the Southern African Development Community. You can read the rest of the series <a href="https://theconversation.com/africa/topics/sadc-malaria-week">here</a>.</em></em></p>
<p>Malaria is a killer that has spent thousands of years adapting to the habits of its victim. Although the first confirmed case of human malaria dates to 450 AD, a millennia and a half later, the world is still battling the parasite that causes this disease. Today at least <a href="http://www.who.int/malaria/media/world_malaria_report_2014/en/">3.3 billion</a> people, or almost half of the world’s population, are at risk of contracting malaria. The heaviest burden is in Africa where an estimated 90% of malaria deaths occur.</p>
<p>To eliminate malaria and alleviate the disease scientists have to develop drugs that kill the parasite in the blood. But to prevent the spread of the disease in a community, these drugs also have to kill transmissible versions of the parasite that develop. </p>
<p>The challenge is that the world is running out of usable antimalarial <a href="http://www.who.int/malaria/media/world_malaria_report_2014/en/">drugs</a>. Antimalarial drugs that are widely used have a limited usable lifespan. This is because parasites develop resistance. The current drugs are becoming less effective as the parasite develops resistance against them. </p>
<p>To tackle this problem, researchers are investigating potential antimalarial drugs with multiple <a href="http://www.biomedcentral.com/content/pdf/s12936-015-0572-z.pdf">targets</a> to overwhelm the parasite and reduce resistance development. Multi-target drugs may also speed up the drug discovery and development process.</p>
<p>The multi-target inhibitors that we are <a href="http://www.biomedcentral.com/content/pdf/s12936-015-0572-z.pdf">studying</a> have been shown to target both the disease causing and transmissible forms.</p>
<h2>Understanding the malaria parasite</h2>
<p>The malaria parasite is an amazing shape shifter. It is able to change its shape in different environments to cause and spread the disease. In infected humans, the parasite lives within red blood cells leading to the symptoms and complications of the disease. The main symptoms include fever, headaches and vomiting which usually appear between 10 and 15 days after the mosquito <a href="http://www.who.int/topics/malaria/en/">bite</a>.</p>
<p>But when a female mosquito bites a human infected with malaria, a special form of the parasite, called a gametocyte, is drawn up from the person along with their blood. This special parasite then develops further in the newly infected mosquito and matures into another form of parasite that can be transferred to another human when the mosquito bites someone else. This leads to the spread of malaria. </p>
<p>With repeated exposure to a drug, the parasite cleverly adapts to the presence of the drug by changing its DNA. This means that the drug target in the parasite is no longer affected by the drug or that the parasite gets rid of the drug before it can reach its target. </p>
<p>To slow down the ability of the parasite to develop drug resistance, malaria medicine has been formulated into a combination therapy. It combines two antimalarial drugs that target different biological processes in a single tablet. It is considerably more difficult for the parasite to simultaneously change both targets in order to become resistant against both drugs. With combination therapies, the parasite has a significantly reduced chance of developing resistance compared to a single therapy. </p>
<p>Even though combination therapies have assisted in slowing down parasite drug resistance, the parasite is developing drug resistance to an antimalarial drug faster than new drugs are being developed and approved. </p>
<h2>A multi-pronged approach</h2>
<p>To increase and sustain the antimalarial armoury, drug developers need to deliver drugs faster and increase the lifespan of the drugs that are in circulation. </p>
<p>The answer to this conundrum may lie in the field of antibiotic drug discovery. </p>
<p>The antibiotic field is currently developing resistance-resistant <a href="http://www.cell.com/trends/pharmacological-sciences/abstract/S0165-6147(14)00172-2">antibiotics</a> that have multiple targets instead of single targets. Instead of a combination therapy that targets two single targets, a multi-target drug has numerous targets which the parasites need to develop resistance against. This makes it exponentially more effective than a combination therapy in resisting resistance. </p>
<p>One example of the outstanding success of this strategy is the TB drug, <a href="http://openres.ersjournals.com/content/1/1/00010-2015.full">SQ109</a>, which is currently in phase II clinical trials. It inhibits multiple targets with potent inhibition of TB cell growth and very low rates of spontaneous drug resistance. </p>
<p>A multi-target drug approach may provide the desired drug discovery breakthrough required to treat malaria. It would speed up the delivery of candidates into clinical practice and decrease drug resistance. </p>
<p>Ultimately, it would stop the spread of malaria by targeting the transmissible forms. In this way, we hope to stay one step ahead of the malaria parasite and make a dramatic difference to curb and eliminate the disease.</p><img src="https://counter.theconversation.com/content/49986/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bianca Verlinden receives funding from the SA National Research Foundation and SA Medical Research Council. </span></em></p><p class="fine-print"><em><span>Lyn-Marie Birkholtz receives research funding from the SA National Research Foundation and the SA Medical Research Council. </span></em></p>
Across the world scientists are trying to find a new drug that the malaria carrying parasite will struggle to develop a resistance to.
Bianca Verlinden, Postdoctoral Research Fellow, Molecular Parasitology, Department of Biochemistry, University of Pretoria
Lyn-Marie Birkholtz, Associate Professor (Biochemistry) DST/NRF South African Research Chair (SARChI) in Sustainable Malaria Control, University of Pretoria
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/49848
2015-11-01T11:07:52Z
2015-11-01T11:07:52Z
Parts of southern Africa are within tantalising reach of eliminating malaria
<figure><img src="https://images.theconversation.com/files/100338/original/image-20151030-16554-1qj7h1i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A young girl plays inside a mosquito net in Kibera, Nairobi. </span> <span class="attribution"><span class="source">EPA/Stephen Morrison</span></span></figcaption></figure><p><em><em>This article is part of a series The Conversation Africa is running as part of the SADC malaria week. You can read the rest of the series <a href="https://theconversation.com/africa/topics/sadc-malaria-week">here</a>.</em></em></p>
<p>There has been a concerted international effort since the early 2000s to tackle malaria. This has led to dramatic reductions in the disease. </p>
<p>World Health Organisation estimates show that in 2015 there were <a href="http://www.who.int/malaria/media/malaria-mdg-target/en/">214 million</a> malaria cases and 438,000 deaths globally. This is a 37% decrease in the incidence rate of malaria compared to 15 years ago and a 60% reduction in deaths.</p>
<p>Most of the gains have happened in Asia and “fringe” areas in Africa, which is at the periphery of distribution of the disease. But the challenge is that sub-Saharan Africa still shoulders 89% of existing cases and 91% of deaths from the disease. </p>
<h2>How successes have been achieved</h2>
<p>Africa has historically had a high transmission rate. Southern Africa has been particularly successful in reducing its case load. The Seychelles and Mauritius have completely eliminated malaria. They have had no new local transmissions in recent years – only some imported cases that were locally diagnosed and treated.</p>
<p>In South Africa there was an exceptional peak of <a href="http://www.scielo.org.za/scielo.php?pid=S0256-95742013001000029&script=sci_arttext&tlng=es">64,622 cases</a> in 2000. Since then case numbers have dwindled to between 6000 and 10,000 in recent years. </p>
<p>This reflects reductions in several of South Africa’s neighbouring countries such as Botswana, Namibia, and Swaziland – where malaria mortality rates are close to zero. </p>
<p>These four countries are in the pre-elimination and elimination stages. Malaria incidence in all of them makes up less than five cases per thousand people. This means they are within sight of eliminating malaria – a tantalising target that South Africa hopes to reach <a href="http://www.scielo.org.za/scielo.php?pid=S0256-95742013001000035&script=sci_arttext&tlng=en">by 2018</a>.</p>
<p>But that reward is proving hard to achieve despite the dedicated efforts by the national malaria control programs in each country. </p>
<h2>The reasons why full elimination is so difficult</h2>
<p>The standard tools used almost universally for malaria control are: </p>
<ul>
<li><p>providing households with insecticide-treated bednets (ITNs);</p></li>
<li><p>indoor residual spraying (IRS) of insecticides against mosquitoes that enter households; and</p></li>
<li><p>dedicated efforts to detect malaria cases and treat them with effective anti-malarial drugs. </p></li>
</ul>
<p>When these three tools are used in combination, they have resulted in the reversal and decline in malaria cases almost globally. But what was once an effective approach to harvest the low-hanging fruit to achieve relatively quick success have now become blunt tools. </p>
<p>The interventions now lack the surgical precision to clear up what is known as “residual malaria”. These are the portion of cases that pop up for reasons that are not always known and do not yield to persistent use of the traditional tools.</p>
<p>A major contributing factor, especially in the case of South Africa, is the large numbers of migrants and visitors from high-transmission malaria countries further north. Although Gauteng, South Africa’s economic hub, was never a problem province, it now has the highest number of cases in the country.</p>
<p>The cases are through infected people entering the country and becoming ill once they have arrived, or vehicles returning from high-transmission countries with malaria-infected mosquitoes hitching a ride.</p>
<p>There are other reasons too. </p>
<p>Some countries do not have a policies to deal effectively with the particular life stages that infect mosquitoes. Malaria parasites have a complex life cycle involving different forms having different target organs and functions. Only one stage – the sexual gametocytes – are able to infect mosquitoes that leads to infecting other people. </p>
<p>Although doctors prescribe medication that kills the numerous asexual parasites in the blood which then cures infected people of the malaria symptoms, it does not effectively inactivate the sexual gametocytes that infect mosquitoes, at least in Africa where the deadliest species of malaria parasite is most common.</p>
<p>There are also chronic systemic challenges. These include a shortage of manpower, funding, lost skills that are not replaced, and a mindset still geared to the decades-long traditional approach to combat malaria. </p>
<h2>New frontier</h2>
<p>Entering the elimination stage is a relatively new frontier for the southern African countries. </p>
<p>There are more hazy possibilities that come into play with residual malaria. This includes the unknown role of secondary vectors. Traditional malaria control tools have targeted a very limited set of mainly <a href="http://www.parasitesandvectors.com/content/3/1/72">three mosquito species</a> with known behaviour. </p>
<p>Addressing these three species has resulted in successes. But with residual malaria we may be dealing with unknown secondary vector mosquitoes that previously played a minor role but now keep the disease ticking over.</p>
<p>Also, across the world there are increasing numbers of countries where mosquito populations are building resistance to available insecticides used for spraying. What is more concerning is that malaria parasites are also developing resistance to the only, and best, available anti-malarial compound, artemisinin.</p>
<p>This resistance is currently still confined to geographic pockets in southeast Asia, but precedents exist where such resistance rapidly spreads to other parts of the globe.</p>
<p>Another concern is loss of political will to continue the high financial and other demands associated with effective malaria programs – and donor fatigue. </p>
<p>Most of the money being poured into malaria control at global scale comes from international donors. Once again precedent has shown that in the face of diminishing returns such donors lose commitment.</p>
<h2>The last lap</h2>
<p>Botswana, Namibia, South Africa and Swaziland – unlike many other African countries confronted with particular economic and political challenges – are very likely to achieve zero local transmission. </p>
<p>The lessons learnt in South Africa and its neighbours is of great importance. There is some urgency in cementing these successes. </p>
<p>But then the real challenge will emerge: the will of national governments to continue funding a program that has achieved its goal. The moment it weakens its defences, malaria is likely to rebound extremely quickly in the face of migration and importation from high-transmission neighbouring countries that are still fighting to bring malaria under control.</p><img src="https://counter.theconversation.com/content/49848/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Professor Leo Braack received funding from Bill and Melinda Gates Foundation and University of Pretoria for research on malaria.</span></em></p>
Several countries within southern Africa are on the brink of eliminating malaria. But there are several challenges ahead.
Leo Braack, Research Chair, Integrated Vector Management in the Vector Control cluster at the Centre for Sustainable Malaria Control , University of Pretoria
Licensed as Creative Commons – attribution, no derivatives.