Malaria has long been a global scourge, killing some 500,000 people a year, more than half of them children under 5. But that may be about to change, thanks to the introduction of a malaria vaccine—the first vaccine ever against a parasitic infection. The shot has been in the works since 1987, at a cost of more than $750 million, mostly funded by the Bill and Melinda Gates Foundation and GlaxoSmithKline. Dubbed Mosquirix, it was recommended for approval by the World Health Organization in October, after a field trial involving 800,000 children in Ghana, Kenya and Malawi. The four-dose regimen was found to cut the risk of infection by 40% and the risk of severe infection by 30%. —Jeffrey Kluger
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