03 June 2025: US health officials have changed their advice to international travellers about measles, saying that Americans should be vaccinated against the virus no matter where they’re going. US residents are recommended to get measles-mumps-rubella shots, anyway. However, the Centers for Disease Control and Prevention (CDC) previously emphasised the importance of vaccination for travellers going to countries with outbreaks.
Things to know about measles outbreak in the US
Last week, the CDC updated its guidance to call for vaccinations for travellers going to all other countries. This change reflects the growing concern about measles transmission during travel, as highlighted by a recent Colorado outbreak stemming from an international flight. As of May 29, 2025, a total of 1,088 confirmed measles cases were reported, according to the CDC.
Ashley Darcy-Mahoney, a researcher at George Washington University’s nursing school, called the update significant. She noted that an outbreak in Colorado last month stemmed from an international flight that landed in Denver. The CDC travel notice change reflects a recognition that people are being exposed to measles not just in countries where it’s spreading but also in airplanes and during travel.
“We’re seeing a shift from localised outbreaks to transmission in transit,” and the CDC seems to be responding to that, Darcy-Mahoney said. The travel notice advises two doses for all Americans ages 1 and older. An early dose is advised for traveling infants ages 6 months to 11 months. The U.S. has seen more than 1,000 measles cases so far this year.
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 US since 2000. Cases and outbreaks in the US are frequently traced to someone who caught the disease abroad.
Summary:
The US faces a measles outbreak across 33 states. Key symptoms include fever, cough, and rash. Vaccination and avoiding exposure are vital to prevent spread.