According to the U.S. Centers for Disease Control and Prevention (CDC), 49 countries are now reporting measles outbreaks.
The CDC stated on March 22, 2024, that travelers to these countries, including the United States, are at risk of measles if they have not been fully vaccinated at least two weeks prior to departure or have not had measles in the past and travel internationally.
The CDC says the majority of measles cases imported into the United States occur in unvaccinated U.S. residents who become infected during international travel.