This drug is used widely around the world against the mosquito-borne disease and can treat an infection in a few days when it is used in combination with other drugs.
Final-stage trial data released on Tuesday showed it gave protection against clinical and severe malaria in five- to 17-month-olds in Africa, where the mosquito-borne disease kills hundreds of thousands of children a year.
Eighty-seven people have now died from the mosquito-borne illness, up from 66 the week before, said the Centers for Disease Control and Prevention (CDC).