Measles cases in the United States have reached a record high since the disease was declared eliminated from the country 25 years ago. Officials had declared measles eliminated in 2000, when there had not been continuous transmission for more than a year.

Measles — one of the world’s most contagious diseases — was declared eliminated in the U.S. in 2000, due to widespread use of the measles-mumps-rubella (MMR) vaccine. The new cases dovetail with a significant drop in vaccination rates.

U.S. measles cases hit 1,277—the worst outbreak since the disease was declared eliminated in 2000, surpassing 2019's peak.