NAPA, Calif. – Another case of measles has been reported in the Bay Area amid nationwide outbreaks of the highly contagious viral disease.
Napa County health officials said this is the first time since 2012 that the county has had a confirmed case.
What we know
The patient was identified as a child who was not vaccinated against measles. Health officials said the boy became ill after a trip to South Carolina, which is facing a massive outbreak.
By numbers
As of Wednesday, South Carolina has reported 646 cases.
Here in California, the state health department website said there have been two cases so far in 2026. With the latest data update on Monday, it is unclear whether this includes the Napa County case.
In 2025, there were 25 cases, with three Bay Area counties among those reporting measles, including a case in the East Bay last month.
Contra Costa County health officials have warned the public of possible exposures in the days leading up to Christmas at locations including stores at the Broadway Plaza shopping center.
‘No threat to public health’ in Napa County
In Napa County, officials said, “At this time, there is no public health threat to the general population.”
The county said it is working with the California Department of Public Health to follow up with people who may have been exposed and to make sure they were up to date on their measles, mumps and rubella (MMR) vaccines.
Detected in sewage water
You are deeper
In Santa Clara County, public health officials there announced Wednesday that the disease was discovered in wastewater samples.
The samples were collected on January 10 from the sewers of Palo Alto, health officials detailed, noting that the shed includes waste from communities in northern Santa Clara County and a small portion of San Mateo County.
Santa Clara County Public Health stressed that the source was unknown and that samples tested over the next five days showed no further evidence in the water.
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“The investigation is ongoing, and it is not yet known if this discovery of measles in the wastewater is connected to recent cases of measles in residents of other Bay Area counties,” the agency said.
Very contagious
Respiratory disease is an airborne virus and spreads easily.
The virus can linger for up to two hours in airspace or on a surface after an infected person leaves an area, according to health experts.
“Simply being in the same room with someone who has measles can result in infection for people who are not immune,” Napa County Public Health Officer Dr. Christine Wu said in a news release.
The best line of defense is to get vaccinated, officials urged.
“Napa County Public Health is recommending that all unvaccinated individuals one year of age and older receive a measles vaccination to protect themselves and those around them,” the agency said.
A record high
Last year, cases in the United States reached a record high in recent decades.
“The United States has passed a milestone in reported measles cases, with 2025 now having the most cases since the disease was declared eliminated in the United States in 2000 and the most cases in more than three decades,” the Johns Hopkins School of Public Health reported in July.
Refer to the US Measles Tracker, that, looking at the latest tracker figures, it showed 2,540 cases. That covered a period of about a year starting from January 1, 2025, to January 16, 2026.
Very preventable
Measles is very preventable.
“It is estimated that when 95% of people in a community are vaccinated, both those individuals and others in their community are protected against measles,” wrote Harvard Health Publishing in an article released earlier this month.
The recent increase in cases can be attributed to the decrease in children being vaccinated.
“Nationally, measles vaccination rates among school-aged children have decreased from 95% in 2019 to 92% in 2023,” the publication said.
Symptoms
Measles symptoms include a rash that typically starts on the face and spreads down the body, as well as fever, cough, runny nose and red eyes.
Symptoms may appear seven to 21 days after exposure.
A person is taken from four days before the rash appears until four days later, with the onset of the rash being considered as day 0.
Those who believe they have contracted measles, the Centers for Disease Control and Prevention urged to contact their health care provider immediately.
“Measles is not just a little rash. Measles can be dangerous, especially for babies and young children,” the CDC said.
If you are unsure about vaccination status, experts advise checking with your healthcare provider.
“The MMR vaccine is very safe and effective, providing lifelong immunity after two doses,” Napa County health officials stressed.