The R21/Matrix-M malaria vaccine, developed by the University of Oxford and produced by the Serum Institute of India, achieved roughly 75% efficacy against malaria in young African children in a phase 3 randomised trial reported in The Lancet. Given that malaria causes hundreds of thousands of deaths annually, concentrated among African children, the result is a significant public health milestone.
The trial randomised more than 4,800 children across Burkina Faso, Kenya, Mali, and Tanzania to receive either R21 or a comparator vaccine, with malaria incidence tracked over 12 months. Randomisation and a control group help isolate the vaccine's effect from other differences between children. The headline 75% efficacy applied to the 5-to-17-month age group under seasonal dosing, timed ahead of peak transmission. The World Health Organization has recommended the vaccine, and the manufacturer projects up to 100 million doses per year at under four dollars each, with Côte d'Ivoire beginning rollout in 2024.
Several caveats shape interpretation. Efficacy was measured over one year, so durability is less certain and motivated the study of booster doses. Protection varied by site and by dosing schedule, meaning the single 75% figure summarises a range of outcomes. Efficacy against clinical malaria is not the same as preventing every infection or death, so the vaccine complements rather than replaces existing tools such as insecticide-treated nets. Real-world effectiveness during large-scale rollout can also differ from tightly controlled trial conditions.