Measles Exposure Alerts Issued at Multiple Transportation Hubs Amid National Outbreak

Health officials have issued warnings regarding potential measles exposure at several transportation hubs across the United States, potentially impacting thousands of travelers. These alerts come as the Centers for Disease Control and Prevention (CDC) reports the nation is experiencing its most significant measles resurgence in 35 years.

In Philadelphia, the International Airport is investigating a possible exposure event that occurred between September 13 and 14. An infected individual traveled through Terminals B and F, as well as connecting areas. The airport serves over 30 million passengers annually, though officials stated the individual did not leave the premises. This incident is separate from a previous possible exposure reported at the Children's Hospital of Philadelphia (CHOP) on September 11. Philadelphia has been battling a measles outbreak, with state data indicating 792 cases as of Monday, including 97 new cases in the preceding seven days. Of these, 155 individuals have been hospitalized, and four have died from measles-related complications. Children under 18 constitute 31 percent of the reported cases.

On the West Coast, California public health officials are also alerting the public to potential measles exposures across multiple counties. An unvaccinated individual traveled through the state between September 12 and 14 via Amtrak trains and buses, with transfers in at least six populated counties. Amtrak trains in California typically carry between 10 to 12 million passengers each year. The infected passenger's route included travel from Chicago to Los Angeles, then to Bakersfield, Stockton, Oroville, Sacramento, and Emeryville in California, before departing for Denver on September 14. The travel routes involved Alameda, Butte, Kern, Los Angeles, Sacramento, and San Joaquin counties. California has reported 59 measles cases across 13 counties in 2026, with 94 percent of those patients being unvaccinated or having an unknown vaccination status. Health officials emphasize the importance of vaccination, noting that measles can lead to severe lifelong consequences, including permanent brain damage, and can be fatal, especially for children.

Missouri has also reported a confirmed measles case involving an individual who used public transportation. In late August, an infected person boarded an Amtrak train in western Missouri, with stops across the state and in Illinois, including Washington, Kirkwood, St. Louis, and Alton. A St. Louis County resident tested positive for measles, marking the county's first confirmed case in two decades, which appears to be the second infection linked to this Amtrak exposure. Additionally, eight businesses in Missouri, including Busch Stadium, may have had exposure to the virus between September 12 and 14, though officials have not confirmed if this is related to the earlier Amtrak incident. Missouri has reported 10 measles cases in 2026, a significant increase from the average of two cases per year.

The CDC reported 3,471 confirmed measles cases in the U.S. as of Thursday, the highest number in three decades and an increase of 1,182 cases compared to the entirety of the previous year. Of these, 39 new outbreaks have been reported in 2026, with 95 percent of confirmed cases linked to these outbreaks.

Health officials urge travelers who may have been exposed at the Philadelphia airport to check their immunity and vaccination status and seek medical attention if they are not immune. Philadelphia Health Commissioner Dr. Palak Raval-Nelson stated, "This week’s measles exposures are a reminder of how important it is for all of us to be up to date on our vaccinations." She added that fully vaccinated individuals have little to fear and contribute to protecting vulnerable populations.

Measles is a highly contagious viral disease, preventable by the measles, mumps, and rubella (MMR) vaccine. Two doses of the MMR vaccine reduce the risk of infection by 97 percent. The CDC notes that the majority of measles cases have occurred in individuals who have not received both doses of the vaccine. Complications from measles are more common in children younger than five and adults over 20, and can include severe illness, permanent brain damage, and death.