California measles case confirmed after exposure at SFO, San Jose sites

Health officials in Santa Clara County confirmed Friday, June 13, that an adult resident had measles and was contagious while moving through San Francisco International Airport and two San Jose businesses. The people most at risk are anyone who was in those places at the listed times, especially anyone without two documented MMR doses or with an unknown vaccination record.

The exposure window at SFO ran from 8:30 a.m. to 11 a.m. on June 8 in the International Terminal, including passport control, customs and international baggage claim. Two San Jose sites were also listed: Trader Joe’s at 635 Coleman Ave. and International Halal Market at 960 E. Santa Clara St., both from 8 p.m. to 10 p.m. that same day. County officials said the resident is believed to have been exposed during international travel and will not be identified for privacy reasons.

Officials told exposed people to review vaccination records, watch for symptoms for 7 to 21 days and call ahead before seeking medical care if illness develops. The county also said unvaccinated exposed people should quarantine as best they can, a warning that carried extra weight as large international events continue to draw heavy travel through the Bay Area.

County Health Officer Sarah Rudman said measles is one of the most contagious diseases in the world and can spread through the air even after an infected person has left a room. California health officials say two doses of MMR vaccine provide 97% protection, and the state warns that measles can remain in the air for up to two hours. Santa Clara County said most residents remain at low risk because of vaccination or childhood exposure, but the exposure notice highlighted how narrow the margin can be when immunity is incomplete.

The alert came amid a broader surge in measles activity. The California Department of Public Health reported 49 confirmed cases in the state as of noon June 8, with 46 in unvaccinated or unknown-status people and three hospitalizations. California had already logged more measles cases and outbreaks in 2026 than in all of 2025, when the state recorded 25 confirmed cases.

Nationally, the Centers for Disease Control and Prevention counted 2,288 confirmed U.S. measles cases in 2025 across 48 outbreaks, and 90% were outbreak-associated. Bay Area public health departments have been on heightened alert as well, after San Francisco recorded its first measles case since 2019 and Santa Clara County had already issued a separate alert in May 2025 for its first confirmed case since 2019.