New malaria vaccine first to reach WHO efficacy demand Malaria kills hundreds of thousands of children each year. Now, an early stage malaria vaccine trial in Africa has shown encouraging results. A malaria vaccine trial in Burkina Faso has shown promising results for the fight against the disease, which killed more than 400,000 people in 2019. The results of the trial, published on Preprints with The Lancet and currently awaiting peer review, showed that the R21/Matrix-M vaccine had 77% efficacy over 12 months of follow-up. It is the first vaccine to meet the World Health Organization's (WHO) Malaria Vaccine Technology Roadmap goal of a vaccine with at least 75% efficacy.