CDC Urges All International Travelers to Be Vaccinated Against Measles

The CDC has updated its guidance on measles vaccination for international travelers, recommending that all travelers be fully vaccinated against measles regardless of their international destinations.¹

While the CDC recommends all US residents receive 2 doses of a measles-containing vaccine to protect against the highly contagious virus,² the agency previously also stressed the vaccination’s importance for those traveling to countries with outbreaks. The updated recommendation to be vaccinated ahead of all international travel comes as measles cases have surged in the US in recent months.³

One dose of the MMR vaccine provides 95% protection against measles, and 2 doses of the MMR vaccine are 97% effective against measles. - Image Credit: Leigh Prather - stock.adobe.com

There were 1088 confirmed measles cases in the US as of May 29, 2025, with 14 outbreaks (defined as 3 or more related cases) reported, according to the CDC.⁴ Out of the 1088 confirmed cases, 977 (90%) were linked with outbreaks. Cases were reported in 33 states: Alaska, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York City, New York State, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont, Virginia, and Washington.

A 6-case outbreak in Colorado in May was linked with a Turkish Airlines flight that landed in Denver, marking the state’s first outbreak among Colorado residents since the mid-1990s.⁵

“Measles is an ongoing risk around the world, and more international travelers are getting infected,” the updated guidance reads.¹ “Travelers can catch measles in many travel settings, including travel hubs like airports and train stations, on public transportation like airplanes and trains, at tourist attractions, and at large, crowded events. Infected travelers can bring the disease back to their home communities, where it can spread rapidly among people who are not immune. CDC recommends that all travelers be fully vaccinated against measles before traveling to any international destination.”

Notably, the CDC’s tally only includes confirmed cases of measles, and the agency acknowledges that it is aware of additional probable cases.⁴ To protect against measles, the CDC recommends all international travelers have 2 doses of a measles-containing vaccine prior to international travel.¹ One dose of the MMR vaccine provides 95% protection against measles, and 2 doses of the MMR vaccine are 97% effective against measles.²

Infants aged 6 to 11 months are recommended to receive 1 dose of the MMR vaccine at least 2 weeks before international travel.¹ Those who receive a dose prior to their first birthday should also follow the recommended routine childhood immunization schedule, which includes a dose at 12 to 15 months and a final dose at 4 to 6 years.

The CDC also recommends that children older than 12 months, teenagers, and adults who are not sure of their measles immunity should receive 2 doses of the MMR vaccine at least 28 days apart prior to traveling internationally. If someone is not sure about their or their travel companions’ immunity, the CDC recommends seeing a clinician at least 6 months ahead of international travel to allow enough time for full vaccination. Individuals who cannot safely receive a measles-containing vaccine but are planning to travel internationally should consider postponing their travel, according to the guidance.

At current childhood vaccination levels, which have been declining, recent research projects that measles would become endemic again within 21 years, and rubella and polio could also return if rates decline further.⁶ Most cases of measles this year have been among individuals who were unvaccinated or had unknown vaccine status. If vaccination levels remain unchanged, current models predict 170,200 hospitalizations and 2550 deaths over the next 25 years. Should rates of childhood vaccination continue to decline, an increase in millions of preventable infections and thousands of deaths could occur.

References

1. Global measles. CDC. Updated May 28, 2025. Accessed June 3, 2025. https://wwwnc.cdc.gov/travel/notices/level1/measles-globe

2. Measles vaccination. CDC. Updated January 17, 2025. Accessed June 3, 2025. https://www.cdc.gov/measles/vaccines/index.html

3. McCormick B. Measles cases surge amid declining vaccination rates. AJMC®. May 9, 2025. Accessed June 3, 2025. https://www.ajmc.com/view/measles-cases-surge-amid-declining-vaccination-rates

4. Measles cases and outbreaks. CDC. Updated on May 30, 0225. Accessed June 3, 2025. https://www.cdc.gov/measles/data-research/index.html

5. Ingold J. Colorado measles outbreak: 3 more cases tied to Turkish Airlines flight that landed at DIA. Colorado Sun. June 1, 2025. Accessed June 3, 2025. https://coloradosun.com/2025/06/01/colorado-measles-outbreak-turkish-airlines-denver-international-airport/

6. Grossi G. Is the US headed for an infectious disease pandemic? AJMC^®. May 2, 2025. Accessed June 3, 2025. https://www.ajmc.com/view/is-the-us-headed-for-an-infectious-disease-pandemic-