Public health officials in Santa Clara County have confirmed that an individual with a contagious case of measles traveled through San Francisco International Airport (SFO) and visited two San Jose grocery stores on Thursday. According to the Santa Clara County Public Health Department, the exposure occurred at SFO’s international terminal between 8:30 a.m. and 11 a.m., followed by visits to Trader Joe’s and the International Halal Market in San Jose from 8 p.m. to 10 p.m. State health data shows California has recorded 49 measles cases this year, a significant increase from previous years, as officials urge unvaccinated residents to monitor for symptoms.
How does measles spread in public spaces?
Measles is one of the most highly contagious viruses known to science. According to the U.S. Centers for Disease Control and Prevention (CDC), the virus travels through the air via respiratory droplets and can linger in a room for up to two hours after an infected person has left. Because the virus remains suspended in the air, individuals do not need to have direct contact with an infected person to contract the disease. Santa Clara County Health Officer Dr. Sarah Rudman states that vaccination remains the most effective defense against transmission, even in high-traffic areas like international travel hubs and retail centers.
Measles is so infectious that if one person has it, up to 90% of the people close to that person who are not immune will also become infected.
What are the symptoms and risks of exposure?
Symptoms of measles typically emerge seven to 10 days after exposure, though the incubation period can extend up to three weeks. According to state health guidelines, early signs include a high fever, cough, runny nose, and red, watery eyes. A characteristic rash usually develops a few days after the initial symptoms. Health officials advise that if you suspect exposure, you should contact a medical provider by phone before visiting a clinic or hospital. This protocol prevents the potential spread of the virus to other patients in waiting rooms, particularly those who are immunocompromised or pregnant.
Why is California seeing a resurgence in cases?
The current rise in measles cases in California is largely tied to international travel and pockets of low vaccination rates. Data from the state indicates that 94% of confirmed cases involve unvaccinated individuals, with more than 80% of those cases occurring in people under 19. This year’s count of 49 cases is nearly double the total recorded in 2025 and marks the highest number of cases since 2019, when 73 were reported. Health officials note that while Bay Area vaccination coverage is generally high, these clusters of vulnerability allow the virus to gain a foothold when brought in from regions with lower immunization levels.
Measles Case Comparison
| Year | Confirmed Cases (CA) |
|---|---|
| 2019 | 73 |
| 2025 (Full Year) | ~25 |
| 2026 (As of June 8) | 49 |
Frequently Asked Questions
What should I do if I was at one of these locations?
If you were at the specified locations during the identified time frames, check your immunization records. If you are unvaccinated, officials recommend self-quarantining and monitoring for fever or rash for 21 days.
Can I get measles if I have been vaccinated?
Two doses of the MMR vaccine are approximately 97% effective at preventing measles. Most people who are fully vaccinated are considered immune.
Where can I get a vaccine?
You can contact your primary care physician or visit the Santa Clara County Public Health website to locate nearby vaccination clinics.
Keep your digital vaccination records accessible in your phone’s health app. This saves time during medical screenings or when traveling internationally.
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