Eleven states in the U.S. have active measles outbreaks as of Tuesday, when North Dakota joined the list after confirming its first cases since 2011.
The U.S. Centers for Disease Control and Prevention's confirmed measles case count is 935, more than triple the amount seen in all of 2024. The three-month outbreak in Texas accounts for the vast majority of cases, with 702 confirmed as of Tuesday. The outbreak has also spread to New Mexico, Oklahoma and Kansas.
Two unvaccinated elementary school-aged children died from measles-related illnesses in the epicenter in West Texas, and an adult in New Mexico who was not vaccinated died of a measles-related illness.
Other states with active outbreaks — which the CDC defines as three or more related cases — include Indiana, Michigan, Montana, Ohio, Pennsylvania and Tennessee.
North America has two other ongoing outbreaks. One in Ontario, Canada, has resulted in 1,243 cases from mid-October through April 29. And the Mexican state of Chihuahua had 922 measles cases and one death as of Tuesday, according to data from the state health ministry. Health officials in Mexico and the U.S. say all three outbreaks are of the same measles strain.
Measles is caused by a highly contagious virus that’s airborne and spreads easily when an infected person breathes, sneezes or coughs. It is preventable through vaccines, and has been considered eliminated from the U.S. since 2000.
As the virus takes hold in U.S. communities with low vaccination rates, health experts fear that spread could stretch on for a year. Here's what else you need to know about measles in the U.S.