The University of Oxford and its African collaborators are testing a new Malaria vaccine that meets WHO criteria for efficacy.
Malaria, a parasitic infectious disease, affects an estimated 230 million people worldwide, mostly in Africa. Nigeria, Liberia, Ghana, the Democratic Republic of Congo, Tanzania, Burkina Faso, Mozambique, and Niger alone account for over half of all cases. To contain this scourge, the World Health Organization (WHO) is counting on the development of a vaccine as the parasite, Plasmodium, becomes increasingly resistant to antimalarial drugs. For now, the WHO is relying on only one formulation, RTS,S/AS01, which works against P. falciparum, the most widespread and aggressive species of the parasite.
This vaccine (RTS,S/AS01) was the first whose effectiveness, estimated at 55%, has been demonstrated in reducing malaria cases in children. It was introduced in 2019 as an additional control measure to those already in place in several African countries.
A new malaria vaccine that is 77% effective
A second malaria vaccine was recently shown to be effective. It is the first vaccine to exceed the threshold of 75% efficacy, bringing it closer to one of the WHO’s key goals: the development of a malaria vaccine with 80% efficacy by 2025. The new candidate was developed by the University of Oxford in collaboration with scientists from Burkina Faso. The vaccine, called R21/Matrix-M, consists of a recombinant parasite-specific protein (the circumsporozoite protein R21) and an adjuvant, Matrix-M.
Phase II clinical trials were conducted in 450 children in Burkina Faso, aged 5 to 17 years. Two concentrations of the adjuvant were tested, with the highest concentration achieving 77% efficacy in preventing the onset of malaria and the lowest concentration achieving a 71% efficacy after three doses and one year of follow-up. A booster vaccine was given just before the peak of infections, during the rainy season.
“These are very exciting results, showing unprecedented efficacy for a well-tolerated vaccine in our trial. We look forward to Phase III to present large-scale safety and efficacy data for this vaccine, which is urgently needed in this region,” said Halidou Tinto, professor of parasitology, director of the IRSS in Nanoro, Burkina Faso, and principal investigator of this clinical trial. The results of this clinical trial have been published on The Lancet’s preprints server.