California warns of measles exposure in six counties after unvaccinated passenger's train travel

Robert F Kennedy Jr. addresses anti-vaccine conference as measles deaths mount

California public health officials are warning of a possible measles exposure spanning multiple counties after an unvaccinated infected passenger traveled through the state via Amtrak trains and thruway buses, making multiple transfers. The California Department of Public Health said the passenger passed through at least six counties — Alameda, Butte, Kern, Los Angeles, Sacramento and San Joaquin — while traveling.

The passenger entered California on an Amtrak train that arrived in Los Angeles on Sept. 10, officials said. From there, the traveler continued to Bakersfield before heading through Stockton, Oroville, Sacramento and Emeryville, eventually leaving California for Denver. Health officials said passengers who were on the same trains or buses, as well as people who were inside stations along the route on the dates involved, were exposed to measles. The state is working with federal partners and local health departments to identify and notify potentially exposed individuals.

“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 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.”

The warning comes as the U.S. faces its largest measles resurgence in more than three decades, fueled largely by growing vaccine hesitancy. Pennsylvania is currently dealing with the country’s worst active outbreak, with 731 confirmed cases across 38 counties so far this year, according to the Pennsylvania health department. At least four people in the state have died from measles-related illness.

Pennsylvania is seeking emergency assistance from the U.S. Centers for Disease Control and Prevention as the outbreak continues to spread. State officials have warned that the request could be withdrawn unless the CDC publicly recognizes the four measles-associated deaths, something U.S. Health Secretary Robert F. Kennedy Jr. previously instructed the CDC not to do.

Kennedy headlined a Washington, D.C., conference of the anti-vaccine organization Children’s Health Defense earlier this week, a group he led for nearly a decade. He addressed the Pennsylvania measles outbreak only briefly during his speech, instead focusing on unfounded fears about vaccines. “In our country we care about rare illnesses and deaths,” Kennedy said. “We care about every child who dies from measles. They get headlines. I’d ask you to care about children who are dying or suffering or being injured by vaccine injuries.”

This month, the Trump administration changed how measles deaths are counted, with the CDC now relying on data from the National Center for Health Statistics, which is used to track mortality trends over time. It remains unclear why the change was made.

The California warning follows another recent mass-exposure incident involving Amtrak. Earlier this week, a person infected with measles traveled on an Amtrak train from Sedalia, Missouri, to Chicago, Illinois, exposing more than 250 people in Jackson County alone.