For the first time in history, annual deaths around the globe from measles have fallen below 100,000, the World Health Organization announced this year. As recently as the 1980s, measles killed 2.6 million people a year.

The decline — a public health triumph, as measles has long been a leading killer of malnourished children — was accomplished by widespread donor-supported vaccination that began in the early 2000s.

The estimated number of deaths fell to 89,780 in 2016, but the figure was released by the W.H.O. only in October.

Measles vaccines were invented in the 1960s. Since 2000, 5.5 billion doses have been given out, according to Gavi, the Geneva-based organization through which most donors support the vaccination effort. The group works with the W.H.O., the United Nations Children’s Fund, the Centers for Disease Control and Prevention, the American Red Cross, the United Nations Foundation and others.