Infectious measles carrier likely visited San Francisco airport, Bay Area county warns

A person who had an infectious case of measles is believed to have traveled through San Francisco International Airport and visited two businesses in San Jose this week.

Santa Clara County’s Public Health Department urged unvaccinated people who may have been exposed to measles to quarantine to help prevent the virus from spreading rapidly through the population.

On Thursday between 8:30 and 11 a.m., a resident of the Bay Area county visited SFO Airport’s international terminal, “including passport control, customs, and international baggage claim area,” according to a statement from the health agency.

Then, between 8 and 10 p.m. that evening, the individual — whom the department is declining to identify or describe due to medical privacy concerns — visited both a Trader Joe’s grocery store at 635 Coleman Ave. and an International Halal Market at 960 E. Santa Clara St., both in San Jose.

Anyone who visited those locations during those times “may be at risk of developing measles seven to 10 days after they were exposed to the individual. Any unvaccinated individual traveling or joining large gatherings should be aware of their increased risk of measles if exposed,” the statement said.

“Exposures like this one remind us of the importance of vaccination. Fortunately, the Bay Area region has strong community immunity, because of our very high rates of vaccination or from childhood exposure decades ago,” said Dr. Sarah Rudman, Santa Clara County’s health officer and public health director.

“Two shots of MMR or MMRV vaccine continue to be the best protection against measles and can stop a measles outbreak in its tracks.”

Anyone who may have been exposed to measles should first determine whether they have been vaccinated against measles by checking their immunization records, the public health department advised. People should monitor for one to three weeks after potential exposure for symptoms including fever, cough, runny nose, rash or red eyes.

If they develop such symptoms, the department statement said, they should call ahead to inform any healthcare provider or facility they plan to visit that they might have been exposed to the virus. Anyone who may have been exposed to measles should immediately consult a medical professional if they are pregnant, an infant, unimmunized, or have a weakened immune system, according to the department.

“Do not attend large gatherings. Measles is one of the most infectious diseases in the world and spreads very rapidly,” the statement said.

The department is working with the state Department of Public Health and the U.S. Centers for Disease Control to conduct contact tracing.

As of June 8, there were 49 confirmed measles cases in California, according to the California Department of Public Health. Of those, 94% were unvaccinated, and more than 80% were under the age of 19.

While the “Bay Area region benefits from very high rates of vaccination against measles,” anti-vax movements, religious beliefs and other factors have led to pockets with elevated unvaccinated rates in multiple states.

As recently as February 2026 and May 2025, Santa Clara County’s health department has warned about potential exposure to measles after people with the virus passed through public places.

During the first eight months of 2025, more than 750 measles cases were reported during a major outbreak in west Texas that hospitalized dozens of unvaccinated residents and killed two people.