Malaria vaccine candidate 77% efficacious in trial, researchers report
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A malaria vaccine candidate was up to 77% efficacious among children aged 5 to 17 months after 12 months of follow-up, according to findings from a phase 2b trial that were published on The Lancet’s preprint server.
The findings are from a randomized clinical trial that was conducted in Burkina Faso, which accounts for around 3% of all malaria cases in Africa, according to WHO. The study is in press with The Lancet.
Source: CDC.gov/James Gathany.
The vaccine is the first to meet WHO’s Malaria Vaccine Technology Roadmap goal of at least 75% efficacy, said Mehreen S. Datoo, MRCP, from the University of Oxford, and colleagues.
“Malaria is one of the leading causes of childhood mortality in Africa,” Burkina Faso Minister of Health Charlemagne Ouédraogo, MD, said, according to a press release issued by Oxford University. “We have been supporting trials of a range of new vaccine candidates in Burkina Faso and these new data show that licensure of a very useful new malaria vaccine could well happen in the coming years. That would be an extremely important new tool for controlling malaria and saving many lives.”
The double-blind, randomized controlled trial included 450 children who were recruited from the area of Nanoro, Burkina Faso, which includes 24 villages and a population of 65,000 people.
Participants were split into three groups. The first two groups received the vaccine, called R21/Matrix-M, and either a low- or high-dose adjuvant. A control group received a rabies vaccine. Doses were administered from May to early August 2019 — before the peak of malaria season.
After 12 months, the vaccine was calculated to be 77% (95% CI, 67%-84%) efficacious among participants in the high-dose adjuvant group, and 71% (95% CI, 59%-79%) efficacious in the low-dose adjuvant group.
The study authors, in collaboration with the Serum Institute of India, are currently recruiting 4,800 children, aged 5 to 36 months, in four African countries for a phase 3 licensure study to assess large-scale safety and efficacy of the vaccine.
Malaria infected an estimated 229 million people in 2019, killing more than 400,000, according to WHO. More than 90% of cases occur in Africa.
WHO said last week that a pilot program launched in 2019 has administered more than 1.7 million doses of another malaria vaccine, RTS,S/AS01 (GlaxoSmithKline), in Ghana, Kenya and Malawi. The goal of the program is to immunize around 360,000 children each year in the three countries.
References:
Datoo MS, et al. SSRN. 2021;doi:10.2139/ssrn.3830681.
University of Oxford. Malaria vaccine becomes first to achieve WHO-specified 75% efficacy goal. https://www.ox.ac.uk/news/2021-04-23-malaria-vaccine-becomes-first-achieve-who-specified-75-efficacy-goal. Accessed April 26, 2021.
WHO. RTS,S malaria vaccine reaches more than 650,000 children in Ghana, Kenya and Malawi through groundbreaking pilot program. 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. Accessed April 26, 2021.
Perspective
Back to TopPhilip J. Rosenthal, MD
This new report, available before publication, describes an apparent advance in malaria vaccines. Previously, the most advanced vaccine under study has been the RTS,S vaccine, which has consistently offered modest protective efficacy, but with some safety concerns; after many years of development, it remains under study, but is not yet prequalified for use by WHO.
The new report describes initial efficacy results for a different, but related vaccine. The R21 vaccine uses the same malaria parasite protein and a similar composition to RTS,S, but with important differences. It was provided to children in Burkina Faso. Compared with controls, children who received 3 monthly doses of the vaccine had an approximately 75% decreased incidence of malaria. The vaccine appeared to be well tolerated. These results suggest that the R21 vaccine may offer strong protective efficacy, and so it may be a valuable new tool against malaria. However, much more study is needed to confirm efficacy, establish safety and determine the appropriate role for this or other malaria vaccines among the multiple tools now available for malaria control.
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University of Oxford. Malaria vaccine becomes first to achieve WHO-specified 75% efficacy goal. https://www.ox.ac.uk/news/2021-04-23-malaria-vaccine-becomes-first-achieve-who-specified-75-efficacy-goal. Accessed April 26, 2021.
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