The World Health Organization endorsed the first vaccine to prevent malaria Wednesday, giving an important stamp of approval in the quest to eradicate the deadly disease. The vaccine, made by GlaxoSmithKline, works by targeting the deadliest malaria pathogen, with studies showing it is 50 percent effective at preventing serious malaria in the first year. No data has emerged on its efficacy in preventing deaths, but a WHO expert told The New York Times its efficacy in preventing severe malaria is “a reliable proximal indicator of mortality.” The vaccine is also the first known vaccine produced against parasites, which cause diseases much more severe than bacteria or viruses. Some countries have shown consternation over whether to adopt a vaccine with a lower efficacy level, but Dr. Pedro Alonso, the head of WHO’s global malaria program, called the release “a historical event.”

“It’s a huge jump from the science perspective to have a first-generation vaccine against a human parasite,” Alonso said. The disease kills about 500,000 people a year, most of them kids in Africa.