A vaccine made of a purified, weakened form of a malaria parasite gave 100% protection in a small clinical trial.

Of six people who were given five intravenous doses of the live-attenuated vaccine and then bitten by infectious mosquitoes, none developed malaria. Five out of six unvaccinated people did get the disease, as did three out of nine patients who received lower doses of vaccine. These levels of protection, reported by Robert Seder at the National Institutes of Health in Bethesda, Maryland, and his colleagues, surpass any previously achieved for a malaria vaccine. The vaccine will now be tested in larger field trials in Africa, which will determine how long protection lasts and whether it works against other strains of the malaria parasite.

Science http://dx.doi.org/10.1126/science.1241800 (2013)