Measles Case on Amtrak Trains Prompts Public Health Alerts Across Multiple California Counties
A hospitalized passenger who traveled extensively via Amtrak and bus from Colorado to California has prompted health officials to notify potential contacts.
Health officials are working to identify and notify individuals who may have been exposed to measles by a passenger who traveled across multiple Amtrak train lines and bus routes in California between September 10 and September 15.
The unidentified individual traveled from Colorado to Los Angeles by Amtrak, then took additional Amtrak trains and buses to Bakersfield, Stockton, Oroville, Sacramento, and Emeryville before returning to Denver. The affected counties in California include Alameda, Butte, Kern, Los Angeles, Sacramento, and San Joaquin.
Measles is a highly contagious respiratory virus that can lead to serious complications, including pneumonia, brain damage, and even death. Health officials are emphasizing the importance of vaccination against measles and are urging anyone who may have been exposed to check their vaccination status. Two doses of the measles, mumps, and rubella (MMR) vaccine provide full immunization.
Individuals who are not fully vaccinated or are unsure of their immunity are advised to consult a healthcare provider. Those who believe they may have been exposed should monitor for symptoms for 7 to 21 days and limit contact with others. Anyone suspecting they have measles should contact a healthcare provider before visiting a medical facility to prevent further spread.
This case highlights ongoing concerns about measles transmission. California has reported 59 measles cases across 13 counties in 2026, with a significant majority of those infected being unvaccinated or having an unknown vaccination status. Nationwide, the Centers for Disease Control and Prevention (CDC) reported 3,294 cases as of September 11, 2026, surpassing the previous year's total. Approximately 95 percent of these cases have involved unvaccinated individuals.
Before the widespread availability of the MMR vaccine in the 1960s, measles caused millions of deaths annually. By 2023, global deaths attributed to measles had fallen to approximately 107,000. However, maintaining herd immunity, which requires about 95 percent of the population to be vaccinated, remains crucial. Current vaccination rates for kindergarteners nationwide stand at 92.4 percent, below the CDC's recommended threshold.