State and Bay Area health officials warned of a possible measles exposure Friday after a person infected with the disease traveled by train from the Midwest through California.
Alameda County and California Department of Public health officials say an Amtrak passenger, infected with Measles, traveled from Chicago, through Sacramento, then to Emeryville, before the last leg of their journey to Los Angeles. They said that person could have infected scores of other passengers all along the way.
Two frequent riders on the Sacramento to the Bay Area route just heard about the possible measles exposure on Saturday.
“That is new news that I’m hearing about. It’s very worrisome,” passenger Elham A said.
“It’s a risk you take in any public space. I don’t think Amtrak is particularly at fault for anything related to that. When you use public transport, if people are being silly, it can affect you,” passenger Henry N. said.
According to officials, the infected passenger started their trip in Chicago on Sep. 10 and arrived in Los Angeles on Sept. 12. The passenger arrived in Bakersfield and traveled to Stockton that same day. On Sept. 13, the passenger traveled from Oroville to Sacramento, and then from Sacramento to Emeryville. On Sept. 14, the passenger left Emeryville to arrive in Denver on Tuesday.
Health experts say measles cases have skyrocketed as vaccination rates have decrease; 3,400 were reported nationwide in 2026, while there were fewer than 2,300 in all of 2025.
“So, we have been having the largest Measles outbreak, in since the last 35 years in this country, and now this person riding on Amtrak, actively infected with Measles, could unfortunately infect people who are not vaccinated,” UCSF Department of Medicine Dr. Monica Gandhi said.
Dr. Gandhi says vaccination rates for the measles-mumps-rubella vaccine have fallen below the critical 95-percent rate across the U.S., and nine out of 10 patients hospitalized with measles are unvaccinated.
“So, we really want 95% rates of vaccination, and the reason Measles is spreading in this country and we’re in this situation, is because we have people who are unvaccinated,” she said.
California does still meet the 95% MMR vaccination rate, but a recent Reuters poll says only about 84% of U.S. citizens have faith in vaccines.
Gandhi says there’s also a risk with vaccinated people who came into contact with the measles positive Amtrak passenger or others actively infected.
She says they can still pick up and carry the disease and transmit it to others.
“The concern is, you could take it home to someone who’s vulnerable, who is not vaccinated, like say a small child,” she said.
The California Department of Public Health urges people to get vaccinated and to monitor for symptoms of a fever coupled with an unexplained rash. They advise anyone who believes they’ve been infected to self-isolate and call a doctor immediately.
State and local health officials are working to identify and notify anyone who may have been infected.
