In response to a concerning rise in measles cases across the U.S., the Centers for Disease Control and Prevention (CDC) has issued a health alert urging all international travelers to ensure they are fully vaccinated against this highly contagious disease before leaving the country. This recommendation applies to all destinations, regardless of outbreak history.

As of late May 2025, 1,088 confirmed measles cases have been reported across 33 U.S. states. About 90% are linked to outbreaks, with at least 62 directly tied to international travel. Most affected individuals were either unvaccinated or had unknown vaccination status. This resurgence is attributed to declining vaccination rates and growing misinformation about vaccines.

Measles is airborne and can survive on surfaces and in closed spaces for up to two hours. High-traffic environments, such as airports and airplanes, pose significant exposure risks. A recent case at Denver International Airport—one of the nation’s busiest—led to a health alert after three infected passengers were identified, prompting hundreds of others to monitor for symptoms.

The MMR vaccine (measles, mumps, rubella) is highly effective. One dose provides 95% protection; two doses increase efficacy to 97%. The CDC recommends international travelers receive two doses at least two weeks before departure. Infants aged 6–11 months should get one early dose, followed by the routine schedule at 12–15 months and 4–6 years.

People unable to get vaccinated for medical reasons should consider postponing international travel. The CDC also advises consulting with a healthcare provider at least six weeks before travel to confirm immunization status.

This measles resurgence underscores the importance of maintaining high vaccination rates and constant vigilance—especially in today’s interconnected world where diseases can cross borders with ease.