Measles outbreak in the United States of America

From 1 January to 20 March 2025, 17 States have reported a total of 378 cases of measles

On 11 March 2025, the World Health Organization (WHO) received a report from the International Health Regulation (2005) (IHR) National Focal Point (NFP) of the United States of America (United States) on the ongoing measles outbreak in the country, notified under IHR because it is an unusual event with potential significant public health impact, with the number of cases and deaths in 2025 exceeding the numbers in previous years.

Additionally, cases linked to the outbreak in the State of Texas, United States, have been reported in Mexico. Measles is a highly contagious, airborne viral disease that can lead to severe complications and death.

From 1 January to 20 March 2025, 17 States have reported a total of 378 cases of measles, including two deaths – the first deaths related to measles in the United States in a decade. The majority of cases are in children who are unvaccinated or have unknown vaccination status, and the overall hospitalization rate is 17%. In 2025, within the larger public health event, there are three distinct measles outbreaks reported, accounting for 90% (341/378) of reported cases.

The Centers for Disease Control and Prevention of the United States (US CDC) and other government agencies are working to control the outbreaks. In 2000, measles was declared eliminated in the United States, since then imported cases of measles have been detected in the country, as the disease remains endemic in many parts of the world. WHO is working closely with countries in the WHO Region of the Americas to prevent the spread and reintroduction of measles.