The Centers for Disease Control and Prevention (CDC) has issued a comprehensive travel warning urging all Americans to ensure they’re fully vaccinated against measles before traveling internationally, as cases continue to rise domestically and globally. The updated guidance, released on May 27, 2025, now applies to all international destinations, regardless of whether there’s a known outbreak in the specific country. This marks an expansion of previous recommendations, which had focused only on countries with active outbreaks.
The warning comes amid alarming statistics showing the United States has recorded more than 1,000 measles cases across 33 states since the beginning of 2025. Furthermore, ABC reports that South Dakota has become the latest state to report its first case this year. CDC officials have also identified 62 instances of travelers infected with measles while on airplanes, with at least one confirmed case of transmission occurring during air travel. The surge in cases correlates with declining vaccination rates nationwide, raising serious concerns among public health officials.
Why This Measles Warning Matters
Measles ranks among the world’s most contagious viruses, spreading through direct contact with infectious droplets or airborne transmission when an infected person breathes, coughs, or sneezes. Airports, train stations, and large public gatherings create ideal conditions for rapid transmission.
Dr. Joshua Clayton, South Dakota’s state epidemiologist, emphasized the high risk for unvaccinated individuals. Speaking to ABC News, Dr. Claton stated, “Individuals who lack immunity from vaccination or past infection are at high risk of measles infection if they have contact with an infected person.”
Health experts stress that the measles, mumps, and rubella (MMR) vaccine provides exceptional protection, proving 97% effective after two doses. The CDC recommends this vaccine as part of routine childhood immunizations, typically administered first at 12-15 months and again at 4-6 years of age. Vaccines can begin as early as 6 months for international travel with children.
The current outbreak has particularly affected several regions, with Texas, New Mexico, and Oklahoma experiencing the most significant clusters of cases. The CDC defines an outbreak as three or more related cases, and 11 states currently meet this threshold. Most cases entering the United States come from unvaccinated American residents who become infected during international travel and then return home.
