The first malaria vaccine has been endorsed by the WHO, according to a report published by The New York Times. The vaccine is given in three doses between 5 and 17 months, with a fourth dose about 18 months later. In clinical trials, it was about 50% effective against severe malaria in the first year, but effectiveness fell close to 0% by the fourth year. Following clinical trials, the vaccine was incorporated into routine immunization programs in Kenya, Malawi, and Ghana, where more than 2.3 million doses have been given to more than 800,000 children in those countries. A modeling study estimated that the use of the vaccine in countries with the highest incidence of malaria could prevent 5.4 million cases and 23,000 deaths in children younger than 5 each year. A trial assessing how a combination of the vaccine and preventive drugs protected children during high-transmission seasons found this approach to be much more effective at preventing severe disease, hospitalization, and death than either method alone.