On May 29, 2026, the U.S. Centers for Disease Control and Prevention (CDC) confirmed 31 new measles cases in a nationwide outbreak that has now reached 1,983 infections, as experts describe sometimes-serious symptoms that can warrant hospital stays, including brain inflammation and pneumonia. 

All but nine of the U.S. infections are locally acquired, with the rest related to international travel. The total for all of last year was 2,288 confirmed cases.

The agency reported a new measles outbreak, for a total of 30 outbreaks. The nation saw 48 outbreaks for the entire year in 2025.

Of this year’s cases, 21% involve children younger than 5 years, and 72% involve kids and young adults up to 19 years. Among all 2026 patients, 92% have been unvaccinated or have an unknown vaccination status. Six percent of patients this year have been hospitalized, compared with 11% last year.

No measles deaths have been reported this year, compared with three last year.

At the IDSA briefing, Ruth Lynfield, MD, Minnesota state epidemiologist, said, “We are worried about measles because it is so contagious, and for some people, it can result in severe disease and complications, including severe dehydration, pneumonia, encephalitis or brain inflammation, and even death. Measles can attack immune memory cells and may increase susceptibility to other infections for a period of time after the acute measles infection. 

“People at high risk for complications include infants and those who are immunocompromised. A person who is pregnant is at high risk for severe disease, including pneumonia. But there is also a higher risk of miscarriage, stillbirth, low birth weight and prematurity for the baby.”