Measles Outbreak Warning: Bay Area Residents Urged to Check Vaccination Status

Measles Exposure Warning: Bay Area Residents Urged to Check Vaccination Status May 30, 2025 Bay Area residents are urged to check their measles vaccination status following a confirmed case of measles in an adult who recently returned from international travel. Health officials have identified three locations with potential exposure: H Mart on Oakland Road in San Jose (May 21, 7:15 PM - 9 PM), a Starbucks on Newark Boulevard in Newark (May 23, 11:45 AM - 2 PM), and Trader Joe's on Great Mall Parkway in Milpitas (May 25, 4:45 PM - 8 PM). "The bad news is that it's one of the most transmissible infectious agents we know," said Dr. Peter Chin-Hong, an infectious disease specialist at UCSF. "Somebody can have measles, be at Trader Joe's, leave, and then two hours later, somebody who is walking into Trader Joe's can get it." Dr. Chin-Hong also noted the good news: high vaccination rates in the Bay Area and the high effectiveness of the measles vaccine. However, he stressed the importance of vaccination, particularly for those who may have only received one dose. Even one dose provides about 93% protection, he said. For those who are unvaccinated and were at the identified locations, he recommends self-isolation for about three weeks. The CDC reports over 1,000 measles cases in the US so far this year, a sharp increase from 285 cases in all of 2024. The virus has even been detected in wastewater in Sacramento. Local health officials are closely monitoring the situation and will hold a news conference tomorrow morning to provide further updates.