• In 2019, 409,000 people died from malaria.
• Cases of malaria have been falling but have recently stalled.
• The RTS,S/AS01 vaccine is the first and only vaccine that targets the parasite P. falciparum, which is particularly deadly and prevalent.
• The vaccine represents decades of work and is a major breakthrough.

In an announcement, the World Health Organization (WHO) has recommended a malaria vaccine for children in areas with moderate-to-high transmission of P. falciparum malaria.

The RTS,S/AS01 (RTS,S) vaccine is safe. Since 2019, healthcare professionals have trialed it in 800,000 children in Ghana, Kenya, and Malawi.

Malaria

According to the WHO, malaria is an infectious disease that occurs due to the transmission of parasites to a person by mosquito bites that carry the infection.

Around 409,000 people died from malaria in 2019, 67% (274,000) of whom were children under 5 years old. In 2019, 94% of deaths and cases of malaria occurred in Africa.

The malaria parasite P. falciparum is particularly dangerous — in Africa, it accounts for 99.7% of estimated cases.

A person will typically only experience symptoms 10–15 days after being bitten by an infected mosquito. Initial symptoms may be mild, including headache and fever, and it can be hard to tell whether they indicate malaria. However, these symptoms can quickly become life threatening without treatment in the first 24 hours.

According to Dr. Matthew B. Laurens, of the Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, and the author of a study in the journal Human Vaccines and Immunotherapeutics, a person with mild malaria has a less than 1% chance of death. However, an individual with severe malaria has a 90% chance of death if they stay at home and a 20% chance if they receive treatment at the hospital.

Well-timed development

According to Dr. Laurens, the development of the RTS,S vaccine comes at an ideal time.

While malaria mortality has reduced due to the promotion of more effective control measures, this reduction in deaths has stalled in recent years. The RTS,S vaccine offers hope that mortality rates will begin to fall again. By 2030, the WHO aims to reduce mortality by 90% from May 2015 levels.

The WHO Director-General, Dr. Tedros Adhanom Ghebreyesus, says, “[t]his is a historic moment. The long-awaited malaria vaccine for children is a breakthrough for science, child health, and malaria control. Using this vaccine on top of existing tools to prevent malaria could save tens of thousands of young lives each year.”

Dr. Matshidiso Moeti, WHO Regional Director for Africa, adds: “[f]or centuries, malaria has stalked sub-Saharan Africa, causing immense personal suffering.”

“We have long hoped for an effective malaria vaccine, and now for the first time ever, we have such a vaccine recommended for widespread use.”

“Today’s recommendation offers a glimmer of hope for the continent [that] shoulders the heaviest burden of the disease, and we expect many more African children to be protected from malaria and grow into healthy adults,” says Dr. Moeti.

Health experts will administer the RTS,S vaccine in four doses to children in areas at high risk of the P. falciparum malaria parasite. It reduces cases of severe malaria by 30%.

“Major achievement”

Speaking to Medical News Today, Prof. Jake Baum, co-director of the Institute of Infection at Imperial College London, United Kingdom, said that the new vaccine was a significant achievement.

“Malaria is unlike COVID-19. As several panel members at the WHO announcement made clear, it’s a complex eukaryotic parasite — more like one of our own cells. It’s not a virus or a bacteria, so making vaccines against it was always going to be much more challenging — [there are] thousands of genes versus [around] a dozen in the SARS-CoV-2 virus.

“It’s also had millennia to co-evolve with our immune system and avoid detection, so it’s a hardened foe to try and attack. As the first licensed vaccine not just for malaria, but the first against any human parasitic disease, it’s a major achievement.”

“Yes, it’s not nearly as efficacious as the COVID-19 vaccines, but it will have [a] significant impact on rates of disease and death. And it sets down a massive benchmark against which we can all work towards beating. So I’d say it was an extremely significant day for vaccinology and for malaria. A public health breakthrough for sure,” said Prof. Baum.

Prof. Baum also noted that while there are no other imminent vaccines or treatments for malaria on the horizon, health experts are beginning to explore many approaches and technologies experts that could be effective.

“There are clinical trials underway for vaccines targeting different lifecycle stages of the parasite, [that is, the] blood stage and transmission — RTS,S targets what’s called the pre-erythrocytic stage, from bite to liver.”

“There are also different vaccine strategies being developed, [f]rom whole sporozoite (parasite) to new innovations that are entirely different. These are at different stages of development — some being trialed extensively in field trials, others still in the lab. RNA vaccines will surely come too.”

“RTS,S gives us a benchmark to measure success in all these vaccines. And I would argue that we will need diversity: diversity in target, diversity in strategy — virus-like particles, messenger RNA, adenovirus, protein, whole parasite — and diversity in manufacturing — […] not just [in the] rich north but in-country in [lower to middle income countries] so that distribution is fair and unencumbered by shipping.”

“Combinations of vaccines or combinations with other interventions — [such as] drugs — can improve efficacy, and this will be something to watch closely in the future.”

“Bottom line, RTS,S must be the beginning of a renaissance in malaria vaccine research, not the end, and that means funding — so funders must see RTS,S as the starting gun to invest in [the] development of new vaccines,” argued Prof. Baum.

Prof. Baum also highlighted how the experience of developing vaccines for COVID-19 may help in the future development of malaria vaccines. However, some of the problems in the equitable distribution of the COVID-19 vaccines also need solving.

“Technologies that rapidly expanded with COVID-19 will undoubtedly feed into improvements in the manufacture, distribution, and delivery of future vaccines. But there’s also been challenges highlighted, most obviously equitable access — seeing how hard it has been getting COVID-19 vaccines to lower middle income countries. That’s something that has to be overcome for malaria, prompting discussions about local manufacturing and local distribution — though RTS,S has shown how it can be done, which is terrific,” said Prof. Baum.

Prof. Baum stressed that while the vaccine is an exciting and important development, more work is necessary to minimize the effects of malaria.

“In a world of shrinking attention spans, no one should read the news and think that malaria is now solved. It isn’t. The vaccine is a landmark, but it’s not 100% by any measure.”

“Malaria control and eventual eradication [are] going to need a diversity of tools and interventions, new drugs, bed nets, vector control and absolutely new vaccines with improved efficacy, longevity of protection, and requiring simpler vaccination regimens.”

“To say it again — RTS,S must be the beginning and not the end of future vaccine research and investment in malaria research.”

“A journey of a thousand miles begins with a single step — RTS,S is one very big step,” said Prof. Baum.

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