California Warns of Measles Exposure on Popular Train Routes

California health officials have issued a warning to passengers who traveled on specific Amtrak trains and connecting buses between September 10 and September 15, 2026, due to potential measles exposure. An unvaccinated traveler, subsequently hospitalized with measles, journeyed through at least six California counties, including Alameda, Butte, Kern, Los Angeles, Sacramento, and San Joaquin, before continuing to Denver, Colorado.

The passenger's route involved significant travel within California, starting from Chicago on September 10 and ending their state transit by September 15. Affected travel included segments from Los Angeles to Bakersfield, Bakersfield to Stockton, Stockton to Oroville, Oroville to Sacramento, Sacramento to Emeryville, and finally Emeryville to Denver.

Officials are urging anyone who may have been on these routes or at the stations during the specified times to check their vaccination status. Two doses of the MMR vaccine are recommended for full immunity. Measles is highly contagious and can lead to severe complications, including permanent brain damage and death, especially in children.

Individuals who believe they were exposed should monitor for symptoms, such as fever, cough, and rash, for up to 21 days. They are advised to contact a healthcare provider by phone before visiting a medical facility to prevent further spread. As of September 14, 2026, California had reported 59 measles cases, with 94% of those affected being unvaccinated or unsure of their status.