Overview:
The first confirmed case of measles in Contra Costa County in two years was announced on Dec. 29, 2025.
The person who contracted the disease was a healthy, vaccinated adult.
Symptoms of measles include fever, cough, runny nose, pink eyes, and rash.
Health officials say anyone who was at several Broadway Plaza stores or two health facilities between Dec. 17 and Dec. 25 could have been exposed.
Contra Costa Health on Monday announced the first confirmed case of measles in Contra Costa County since 2023.
The person who contracted the highly contagious virus was a healthy young adult who had been fully vaccinated against measles abroad, said Dr. Lisa Rodelo, deputy health officer at Contra Costa Health. The person completed home isolation and is recovering well, Rodelo told Richmondside.
Measles is spread through airborne droplets when an infected person coughs or sneezes. Common symptoms include fever, cough, runny nose, pink eyes and rash. Symptoms can develop seven to 21 days after exposure.
County health officials are alerting people who might have visited multiple stores in Walnut Creek’s busy Broadway Plaza, on Dec. 17 and 18, or two health facilities between Dec. 21 and 25 (one in Lafayette), of a potential measles exposure. People who were in these locations on the given days should contact their doctor if they develop any concerning symptoms.
Those most at risk of serious complications from measles are the unvaccinated, babies under age 1, pregnant people and the immunocompromised.
Potential measles exposure locations in Walnut Creek and Lafayette
Dec. 17 or Dec. 19: Anthropologie, 1149 South Main St., Walnut Creek
Dec. 18: Macy’s, 1320 Broadway Plaza; ALO, 1292 Broadway Plaza, Ste. 1106; Apple Store, 1200 South Main St. (all in Walnut Creek)
Dec. 21: STAT Med, 3799 Mount Diablo Blvd. #100, Lafayette
Dec. 23-24: Kaiser Walnut Creek Emergency Department, 1425 South Main St., Walnut Creek
Overall, vaccination rates in Contra Costa County are high, according to Contra Costa Health. While there have been 25 cases of measles in California in 2025, this case is the first in the county since 2023.
The California Department of Public Health (CDPH) recommends babies receive their first dose of the measles vaccine at 12 months and the second dose between ages 4 and 6. One dose of the vaccine is 93% effective against measles and two doses are 97% effective against measles, according to the CDC.
“Vaccines, such as the ones that prevent measles, save lives. I’ve seen it personally,” said Rodelo.
If exposed to measles, close to 90% of unvaccinated people will contract the disease, CDPH wrote on its measles webpage.
What to do if you think you have measles
If you have mild symptoms, such as rash, pink eyes, runny nose, and mild cough or fever without chest pain or shortness of breath, you can call the county nurse advice line at 877-661-6230.
If you have moderate or severe symptoms such as shortness of breath, chest pain, confusion, or high fever, see a doctor. You can go to an emergency room or urgent care clinic but alert the staff there about your symptoms before you arrive.
County and state vaccination rates are important to track because they are an indicator of community immunity thresholds, or how much of the population has to be immunized to limit the spread of infection in a community.
According to the American Academy of Pediatrics, the community immunity threshold for measles is 92% to 94%. This means that 92% to 94% of the population has to be immunized to limit the spread of measles.
At least 94% of eligible students in the West Contra Costa Unified School District had been fully vaccinated against measles as of 2023, EdSource reported. These numbers are an improvement compared to 2021 data, which showed that at Martin Luther King Jr. Elementary and Tara Hills Elementary, less than 90% of all students had been fully immunized against measles.
Contra Costa County Board of Supervisors District 1 Supervisor John Gioia told Richmondside he is heartened by the high vaccination rate in Contra Costa County. But he is still cautious, pointing to his son, who recently had a stem cell transplant and is currently immunocompromised.
Due to his son’s condition, Gioia said he is more likely to wear a mask indoors. He also urges everyone to get vaccinated against measles.
“ We want everyone who’s eligible for vaccination to get vaccinated, to get lifetime protection,” said Gioia, “because it’s not just about keeping yourself healthy, it’s keeping our community healthy, keeping others healthy.”
A resurgence of the illness made headlines during an outbreak in west Texas, where as of Aug. 12 there had been 762 confirmed cases and two deaths of otherwise healthy unvaccinated school-age children.
Also, earlier in December, measles outbreaks were reportedly increasing along the Utah-Arizona border and in South Carolina, where hundreds are in quarantine, according to a Dec. 11 Associated Press report.
Measles FAQ
There is no at-home test for measles. You can check your immunity to measles with a blood test.
Measles is a highly contagious respiratory virus that can cause serious complications, including pneumonia and encephalitis (inflammation of the brain).
There is a safe and effective vaccine against measles. The California Department of Public Health recommends one dose at 12 months old and a second dose at ages 4 to 6. You can always get vaccinated if you did not receive the vaccines at these ages.
Measles vaccines are offered at most doctors’ offices and at the county public health clinics. Those without private insurance can make an appointment at a county health clinic or call 925-608-5350.
Infected person had been vaccinated
Notably, the Contra Costa County case is a breakthrough infection, in which a person who is fully vaccinated is diagnosed. Occasionally, someone who is vaccinated may experience waning immunity six or more years after receiving a vaccine, according to a review article in the New England Journal of Medicine.
While there is no at-home test for measles, people can check their immunity levels with a blood test. A doctor can offer advice if you are unsure about your vaccination status, or if you want to confirm your immunity.
A specific nose and throat swab is required to confirm if someone is actively infected with measles. This swab can typically be done at an emergency room but let heath care provider know about your symptoms before you arrive.
Both Gioia and Rodelo hope to increase awareness about measles and they encourage everyone to get vaccinated.
“Our health department is ready, willing, and able to vaccinate,” Gioia said. “ We are all healthier when we are all healthier.”
