Malaria vaccine loses effectiveness over several years: study

An experimental vaccine against malaria known as Mosquirix—or RTS,S—weakens over time and is only about four percent effective over a seven-year span, researchers said Wednesday. The findings, published in the New England Journal of Medicine, are based on a phase II clinical trial involving more than 400 young children in Kenya. There is currently no vaccine against malaria on the world market and Mosquirix—developed by the British pharmaceutical giant GlaxoSmithKline—is the experimental vaccine in the most advanced stage of development. It has also been tested in a vast clinical trial that spanned seven African nations, and last year the European Medicines Agency gave it a “positive scientific opinion” regarding its use outside the European Union. But the current study, involving 447 children from five to 17 months of age, suggested otherwise. Some of the infants were given three doses of the malaria vaccine, while others received a vaccine against rabies for comparison. In the first year,...