A new malaria vaccine has raised eyebrows in early testing and revived the dream of curbing a disease that killed more than a million people in 2010—most of them children, NBC News reports. Only 57 volunteers were involved in the US test, says Science Daily, but all who received five doses were fully protected from malaria. "Clearly the results that these authors obtained are really very impressive," says a scientist working on a separate vaccine.
But the new vaccine, dubbed PfSPZ, has its own problems. It must be injected intravenously, a hurdle that may keep it from large populations. Also, no one knows how long it lasts or whether it guards against multiple malaria strains living in the wild. Neat fact: PfSPZ is an immature version of a malaria parasite, made weaker by irradiation. Scientists have long known that bites from infected, irradiated mosquitoes give people protection—but up to 1,000 mosquito bites were needed for it to really work.