Public health agencies in the San Francisco Bay Area have issued an urgent warning to travelers and local shoppers following a newly confirmed case of measles in a South Bay resident. According to officials from the County of Santa Clara Public Health Department, the individual visited several highly populated public spaces—including San Francisco International Airport (SFO) and two retail businesses in San Jose—while in the highly infectious phase of the virus.
The health advisory, released on Saturday, June 13, 2026, aims to identify individuals who may have been exposed to the virus on Monday, June 8, 2026. Because measles is exceptionally contagious and can linger in the air long after an infected individual has departed, authorities are urging the public to check their vaccination records and remain vigilant for early symptoms.
Exposure Locations and Specific Timelines
The Santa Clara County Public Health Department, working in coordination with the California Department of Public Health (CDPH) and the Centers for Disease Control and Prevention (CDC), has mapped out the exact times and locations where the public may have encountered the virus. Individuals who were present at the following sites during these windows are considered potentially exposed:
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San Francisco International Airport (SFO) – International Terminal: The infected individual arrived via an international flight on the morning of June 8, 2026. The risk window spans from 8:30 a.m. to 11:00 a.m. Exposure areas include passport control, customs screening lanes, and the international baggage claim area.
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Trader Joe’s (San Jose): Located at 635 Coleman Ave, San Jose, CA 95110. The individual visited this grocery store on the evening of June 8, 2026, between 8:00 p.m. and 10:00 p.m.
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International Halal Market (San Jose): Located at 960 E Santa Clara St., San Jose, CA 95116. The individual visited this location concurrently or shortly around the same evening window on June 8, 2026, from 8:00 p.m. to 10:00 p.m.
Health authorities specified that the patient is an adult who is believed to have contracted the virus during recent international travel. To maintain patient confidentiality and conform to medical privacy laws, local public health officials stated that no further identifying details regarding the individual’s identity, flight number, or specific origin country will be released.
High-Risk Groups and Immediate Guidelines
Because measles poses a severe threat to certain vulnerable populations, county health officials are instructing specific high-risk groups to contact their healthcare providers immediately if they suspect they were at any of the exposure sites during the specified times. This includes:
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Pregnant individuals
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Infants under the age of 12 months
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Individuals with severely weakened immune systems (immunocompromised)
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Anyone who is entirely unvaccinated against measles
For the general public, the primary recommendation is to check personal immunization histories. Bay Area residents can verify their status digitally via the state’s official vaccine portal at MyVaccineRecord.cdph.ca.gov or by contacting their primary care physicians.
Those who may have been exposed are advised to monitor their health for 7 to 21 days following the June 8 date. Public health guidance strictly stipulates that if an individual begins to display symptoms, they must call ahead to their medical facility before arriving in person. Advance notice allows clinics, urgent care centers, and emergency rooms to implement isolation protocols, protecting other patients, staff, and visitors from airborne transmission. Additionally, anyone experiencing symptoms must refrain from attending large public gatherings or community events.
Understanding Measles Transmission and Symptoms
Measles stands as one of the most infectious transmissible viral diseases known to modern medicine. The virus travels through respiratory droplets when an infected person talks, coughs, sneezes, or breathes. Crucially, the virus can remain suspended and active in the air for up to two hours after the contagious person has exited an enclosed room or space. Among individuals who lack immunity through vaccination or prior infection, the transmission rate is staggering: approximately 90% of unvaccinated people who are exposed to the virus will go on to contract it.
Symptoms generally materialize between 7 and 21 days following exposure. The progression of the illness typically mirrors these phases:
| Phase | Typical Timeline | Common Presentation and Medical Manifestations |
| Prodromal Phase | Days 1–4 of symptoms | High fever, persistent hacking cough, coryza (runny nose), and conjunctivitis (red, watery eyes). |
| Enanthem Phase | Just before the rash | Small, distinctive blue-white spots (known as Koplik’s spots) may appear inside the mouth on the lining of the cheek. |
| Exanthem Phase | Days 3–5 after symptoms start | A flat, red maculopapular rash breaks out, typically starting at the hairline or face and spreading downward over the neck, trunk, arms, and legs. |
While many individuals recover without long-term consequences, measles can cause severe health complications, including severe pneumonia, permanent hearing loss, encephalitis (acute swelling of the brain), and death, particularly in young children and adults over the age of 20.
Contextualizing California’s 2026 Measles Data
This recent exposure comes amid a broader national and state-level rise in measles cases observed across 2025 and 2026. Data maintained by the California Department of Public Health reveals a notable uptick in viral activity, frequently driven by international travelers returning to domestic hubs without adequate vaccine protection.
According to official CDPH surveillance data tracking measles activity in California for 2026, there have been 49 confirmed cases statewide. This represents a significant shift from preceding years, which recorded fewer cases overall:
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2023: 4 confirmed cases statewide
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2024: 15 confirmed cases statewide
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2025: 25 confirmed cases statewide
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2026 (Year-to-Date): 49 confirmed cases statewide
State epidemiology reports highlight that the vast majority of these infections are entirely preventable. Specifically, health officials confirmed that 94% of California’s 49 confirmed cases in 2026 occurred in unvaccinated individuals, prompting a renewed push from medical professionals for state residents to check their immunizations before traveling.
Community Immunity and the Importance of the MMR Vaccine
Despite the warning, local health directors emphasize that the threat of a widespread, uncontrollable outbreak remains low in the immediate region due to historically high local immunization rates.
“Exposures like this one remind us of the importance of vaccination,” noted Dr. Sarah Rudman, Health Officer and Public Health Director for the County of Santa Clara, in an official statement accompanying the press release. “Fortunately, the Bay Area region has strong community immunity, because of our very high rates of vaccination or from childhood exposure decades ago.”
The standard protocol for long-term protection against the virus involves the MMR (Measles, Mumps, and Rubella) vaccine. Clinical data confirms that a single dose of the MMR vaccine is roughly 93% effective at preventing measles, while the recommended two-dose regimen provides 97% lifelong protection.
Under routine California childhood immunization schedules, children are advised to receive their first MMR dose between 12 and 15 months of age, with the second dose administered between ages 4 and 6. For individuals preparing for international travel, public health bodies recommend a tailored approach: infants aged 6 to 11 months should receive an accelerated single dose before departure, while adults and older children should ensure they have documented proof of both standard doses. Under California health regulations, the MMR vaccine is classified as a routine preventative service and must be covered by nearly all forms of health insurance across the state.
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