Deaths from measles have fallen by 60% worldwide since 1999, an achievement that campaigners describe as “a major public health success.” Progress against measles—one of the world's most infectious diseases and a big killer of children—has exceeded the United Nations' goal to halve deaths from the disease between 1999 and 2005, largely because of an “unprecedented decline” in Africa.

The World Health Organization, Unicef, and partners in the Measles Initiative—the American Red Cross, the US Centers for Disease Control and Prevention, and the United Nations Foundation—made the announcement last …