As international travel surges this summer, so does the risk of measles infection. According to the Korea Disease Control and Prevention Agency (KDCA), 65 measles cases have been reported domestically as of July 5, a 40 percent increase from last year. A striking 70.8 percent of these cases were imported from overseas, most commonly from Vietnam, followed by Thailand, Italy, Uzbekistan and Mongolia. Another 19 cases were linked to domestic transmission from imported infections. Measles, an extremely contagious virus, is spreading rapidly again in parts of Southeast Asia, where many Korean travelers vacation. Countries like Cambodia, the Philippines, Laos and Vietnam have seen steep rises in measles cases. The KDCA warns that with global vaccination rates declining post-COVID, even brief visits to outbreak regions could expose unvaccinated travelers to the virus. What is measles? Measles is an airborne respiratory disease caused by the measles morbillivirus. It spreads easily through coughing, sneezing, or even breathing the same air as an infected person. It is remarkably contagious. Over 90 percent of susceptible individuals will contract the virus if exposed. Symptoms appear after an incubation period of 7-21 days (but typically 10–12) and begin with fever, cough, runny nose and conjunctivitis. A few days later, a distinctive red rash spreads from the face to the rest of the body, often accompanied by small white spots inside the mouth. Severe cases may develop complications like pneumonia, diarrhea, middle ear infection, and in rare instances, encephalitis or subacute sclerosing panencephalitis. Global measles outbreaks rising According to recent data from the World Health Organization, measles continues to pose a serious global health threat, with approximately 360,000 cases reported worldwide in 2024. The disease remains prevalent not only in regions such as Europe, the Middle East, and Africa, but also in Southeast Asia, a popular destination for Korean travelers. In 2025, several countries in the Western Pacific region reported notably high measles incidence rates. Mongolia recorded 377 cases, translating to 257.5 cases per million people, while Cambodia reported 1,097 cases, Laos with 288 cases and, Malaysia with 336 cases. This resurgence is partly attributed to declining global vaccination coverage during the COVID-19 pandemic, leaving gaps in herd immunity. As international travel rebounds, unvaccinated or under-vaccinated individuals are more likely to encounter the virus and risk bringing it back home, potentially sparking secondary outbreaks. Who is most at risk? Among the 65 domestic cases this year, 76.9 percent were adults, and 55.4 percent had either not been vaccinated or were unsure of their vaccination history. Infants under 12 months, pregnant women, and immunocompromised individuals are especially vulnerable to severe outcomes and should avoid travel to outbreak-prone regions when possible. How to prevent it? Measles is preventable with two doses of the MMR vaccine (measles, mumps, and rubella), typically administered at 12–15 months and again at 4–6 years of age. For travelers under 12 months visiting high-risk areas, the KDCA recommends accelerated vaccination between 6–11 months. Children and adults with incomplete or uncertain vaccination records should get vaccinated at least two weeks before departure. Travelers can also practice good hygiene, including frequent handwashing and mask-wearing in crowded settings. If fever, rash or respiratory symptoms appear within three weeks of returning from overseas, seek medical care immediately and inform your provider of your travel history. Medical institutions are advised to report any suspected cases to local public health centers to prevent further spread. “Please make sure your measles immunizations are up to date before you go abroad,” said KDCA Commissioner Jee Young-mi. “And if you suspect any symptoms after travel, protect others by visiting a medical facility promptly with a mask on.”