California officials warn of possible measles exposure in 6 counties due to infected Amtrak rider
State public health officials are warning about a possible measles exposure across multiple California counties after an infected passenger traveled across the country on trains and buses.
The California Department of Public Health said the unvaccinated passenger traveled through the state using Amtrak trains and thruway buses with transfers in at least six counties: Alameda, Butte, Kern, Los Angeles, Sacramento and San Joaquin.
Measles is a highly contagious viral disease. People who are not vaccinated, particularly young children and pregnant people, face the highest risk of severe illness and even death, according to officials.
The passenger arrived in California from an Amtrak train to Los Angeles on Sept. 10, according to officials. After arriving in Los Angeles, they took a route to Bakersfield and then went to Stockton, Oroville, Sacramento, and Emeryville before leaving the state to Denver.
Here is the route the passenger took:
Sept. 10: Departed Chicago at 1:30 p.m.Sept. 12: Arrived at Los Angeles Union Station on Sept. 12 at 8:12 a.m.Sept. 12: Departed Los Angles at 10:55 a.m. and arrived at Bakersfield station at 1;45 p.m.Sept. 12: Departed Bakersfield at 2:02 p.m. and arrived at Stockton—San Joaquin St Station at 6:29 p.m.Sept. 12: Departed Stockton at 6:15 p.m. and arrived at Oroville bus/thruway stop at 6:05 p.m.Sept. 13: Departed Oroville at 4 p.m. and arrived to Sacramento Valley Station at 6:05 p.m.Sept. 13: Departed Sacramento at 6:53 p.m. and arrived to Emeryville Station at 8:36 p.m.Sept. 14: Departed Emeryville at 8:25 a.m. and arrived to Denver at 6:59 p.m.
Officials said people who were passengers on those trains or buses or who were at the stations on those days have been exposed to measles. Officials added it’s working with federal partners and local health departments to notify people who may have been exposed.
“This case, along with previous measles outbreaks in California this year, serve as reminders of the importance of vaccination against measles,” Assistant State Public Health Officer Dr. Rita Nguyen said in a statement. “The measles-mumps-rubella (MMR) vaccine is safe and provides long-lasting protection against measles. Vaccination protects both our own families and those who are too young to be fully vaccinated.”
As of Sept. 14, 2026, a total of 59 measles cases have been reported in 13 counties in California, according to officials. Patients were unvaccinated or had unknown vaccination status in 94 percent of cases.
What to do if you have been exposed or have symptoms
Officials said to monitor symptoms, such as watching for a fever and/or unexplained rash from seven to 21 days after exposure. If symptoms develop, officials urged people to call your doctor for guidance.
If anyone suspects they have measles, it’s recommended to call their health care provider before visiting any health care facility to avoid exposing others.
People who are not vaccinated against measles or are unsure of their status are recommended to contact their doctor about receiving the vaccine. Two doses of the vaccine are needed to be fully immunized, officials said.
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