The county said the person was believed to have been exposed during international travel and later moved through SFO's International Terminal, including passport control, customs and international baggage claim, between 8:30 a.m. and 11 a.m. on 8 June. The same notice listed potential exposure that evening at Trader Joe's on Coleman Avenue in San Jose from 8 p.m. to 10 p.m. and at International Halal Market on East Santa Clara Street from 8 p.m. to 10 p.m.
The county notice did not link the resident to a World Cup event. It said people should be aware of increased measles risk when traveling or joining large gatherings, and the San Francisco Chronicle reported that no other cases had been identified when the notice was issued. That distinction matters because one confirmed exposure does not establish an outbreak linked to the tournament.
Measles can spread through the air when an infected person breathes, coughs or sneezes, according to the Centers for Disease Control and Prevention. The CDC says symptoms usually begin 7 to 14 days after infection and can include fever, cough, runny nose, red eyes and a rash. Public-health agencies commonly monitor exposed people for up to 21 days because symptoms can appear later in that window.
The CDC's national measles data page said 2,073 confirmed cases had been reported in the United States in 2026 as of 11 June, including cases in California and 10 cases among international visitors. The CDC says two doses of the measles, mumps and rubella vaccine are 97% effective at preventing measles, while one dose is 93% effective.
The mass-event context is surveillance, not proof of tournament spread. The Pan American Health Organization said on 2 June that countries preparing for the 2026 FIFA World Cup should strengthen surveillance and vaccination readiness for communicable diseases, including measles. PAHO's advice reflects the practical risk of large travel flows: imported infections can be harder to trace when many visitors move through airports, hotels, fan zones and public transport.