Unvaccinated Amtrak passenger with measles travels across six California counties, prompting exposure alert

An unvaccinated traveler infected with measles rode Amtrak trains and thruway buses across six California counties from September 10 to September 15, 2026, before being hospitalized. The California Department of Public Health has issued exposure alerts for transit stops including Los Angeles, Sacramento, and Emeryville. The incident comes amid a major national surge, with the CDC reporting 3,471 confirmed cases across 45 states, marking the highest U.S. measles caseload since 1991.

Amtrak measles exposure across California

• ▪The infected traveler's route included stops in Los Angeles, Bakersfield, Stockton, Oroville, Sacramento, and Emeryville, California, before the traveler arrived in Denver, Colorado.
• ▪The California Department of Public Health published the traveler's itinerary online, warning that anyone present at those transit locations during the specified times may have been exposed.
• ▪An unvaccinated traveler infected with measles traveled by Amtrak trains and thruway buses across six California counties from September 10 to September 15, 2026, prompting public health exposure warnings.

Unvaccinated traveler hospitalized

• ▪The unidentified, unvaccinated traveler was hospitalized after completing the five-day journey from Chicago to Los Angeles and across California.
• ▪California has recorded 59 measles cases across 13 counties in 2026 as of September 14, with over 90% of cases occurring in unvaccinated individuals or those with unknown vaccination status.

Measles transmission risk

• ▪Measles is a highly contagious infection that can cause severe, lifelong consequences, including permanent brain damage, and can be fatal, particularly for children.
• ▪Measles symptoms typically appear seven to 10 days after exposure and include fever, cough, runny nose, red eyes, and a rash.

MMR vaccination guidance

• ▪The California Department of Public Health advises unimmunized individuals exposed one to three weeks ago to quarantine at home and monitor for symptoms for 21 days.
• ▪Dr. Peter Chin-Hong of UCSF stated that individuals exposed to measles within the past week can still receive the vaccine to prevent infection due to the virus's three-week incubation period.

2026 US measles outbreak

• ▪The United States is experiencing its highest measles caseload since 1991, with the Centers for Disease Control and Prevention reporting 3,471 confirmed cases across 45 states and Washington, D.C., as of September 18, 2026.
• ▪Ninety-five percent of the 3,471 confirmed measles cases in the United States in 2026 involve individuals who are unvaccinated or have an unknown vaccination status.
• ▪According to World Health Organization data compiled by FactCheck.org, the United States had 13.2 measles cases per 1 million people as of September 14, 2026, ranking 65th worst out of 169 countries.

Debatable claims

• ▪The rising US measles caseload constitutes a public health crisis
• ▪Amtrak should require passengers to be vaccinated against highly contagious diseases