New Measles Cases in the Bay Area: How to Check Your Vaccination Status and Who Needs a Booster

Napa and San Mateo Counties confirmed two new measles cases on Wednesday — Napa County’s first measles patient since 2012.

The announcements of the Bay Area’s second and third cases this year appear to make the region the home of California’s only reported measles cases in 2026 so far, amid outbreaks across the country of the highly contagious viral illness.

San Mateo County confirmed its second 2026 case of measles in a county resident Wednesday, after previously detecting an earlier case — the first measles detection in the state this year— on Jan. 8. Both patients are adults who had recently traveled outside the United States, according to county spokesperson Preston Merchant. San Mateo’s only 2025 case was also related to international travel, Merchant added.

The Napa County Health & Human Services Agency confirmed that its case of measles was in an unvaccinated child who became ill after traveling out of state to South Carolina, where the disease is currently surging. Health officials in the county have said there is no health risk to the general population, regardless of where in the Bay Area you are, and are working with the California Department of Public Health to notify anyone who may potentially have been exposed by the child.

Nonetheless, Dr. Christine Wu, public health officer for Napa County, urged anyone in the Bay Area who isn’t vaccinated to contact their healthcare provider and seek out the shot. “We don’t know when a case will pop up,” she said. “And so, your best protection is to get vaccinated at this point.”

• Jump straight to:  Who should get a measles booster?

While San Mateo’s first 2026 measles patient was unvaccinated, the second reported having received only one dose of the combined Measles, Mumps, and Rubella (MMR) vaccine as a child, which Merchant said San Mateo health officials haven’t yet been able to confirm.

Two doses of the MMR vaccine are recommended for maximum protection against measles.

But what if you were vaccinated against measles as a child, are you still up to date? Do you need a booster dose? Keep reading for what to know about measles in the Bay Area and around the country right now, how the measles vaccine works and which groups should speak to their health care provider about finding another shot. Or jump straight to:

• Is there a measles outbreak in the Bay Area?
• When would I have received the MMR vaccines?
• Can you still get measles if you’re vaccinated?

What’s the measles risk in the Bay Area right now?

Measles is a highly contagious virus spread through direct contact with infectious droplets and through the air when a person with measles breathes, coughs or sneezes.

Symptoms of measles include fever, cough, runny nose and pink eye, followed a few days later by a rash. These symptoms can emerge between seven and 21 days after exposure. In some people, measles can be fatal. In others, the impacts of an infection can linger — or appear — years afterward.

Following the second San Mateo case, a contact tracing investigation has been completed with “the exposed persons identified,” said Merchant. There are no suspected secondary cases, he confirmed.

About one in five unvaccinated people who become infected with measles will require hospitalization, according to the CDC.

In recent weeks, Stanford University’s WastewaterSCAN team — which monitors viruses in human sewage — has detected multiple instances of measles in wastewater around the Bay Area. Measles was also recently detected in wastewater from Santa Clara and Solano Counties, neither of which have reported any positive measles cases this year.

Does this mean there’s a measles outbreak in the Bay Area — or California — right now?

No. CDPH defines an “outbreak” as three or more related cases. The two San Mateo cases and Napa case are all unconnected.

The last major measles surge in California was in 2019, when 41 cases were associated with six separate outbreaks, bringing the state’s yearly total to 73. The largest outbreak that year resulted in 21 individual measles cases. Before that, an outbreak associated with Disneyland visits resulted in at least 131 Californians being infected with measles between December 2014 and April 2015.

What is the state of measles in the U.S. right now?

The California Department of Public Health’s statewide measles dashboard was last updated on Monday and doesn’t reflect the new Bay Area case count. (The dashboard is updated weekly and CDPH declined to provide a more up-to-date measles count to KQED before the dashboard’s next update on Jan. 27.)

According to the CDC’s most recently-available data from Jan. 14, 171 cases of measles have already been reported around the U.S. so far in 2026. The majority of those cases are in South Carolina, which has reported 145 cases to the CDC this month alone.

Nationwide, 95% of measles cases in January were in people who weren’t vaccinated or whose vaccination status was unknown. Around 85% of patients were under the age of 20.

Last year saw a total of 2,144 confirmed cases,  according to the CDC data — the highest since the U.S. eliminated the disease in the year 2000. These included 25 cases of measles in California, including Bay Area cases in Contra Costa, San Mateo and Santa Clara counties.

The CDC defines “elimination” as having new cases that stem only from international travel, when someone is infected abroad and then re-enters the U.S. In the 1990s, cases reached levels as high as 27,808.

But now, as cases continue to climb in South Carolina, experts have warned that the U.S. is at risk of losing this elimination status for measles. In April, the Pan American Health Organization, an office of the World Health Organization, will assess whether the same measles strain that caused a major outbreak in Texas almost a year ago has continued to spread uninterrupted — which would see the WHO conclude that measles is no longer eliminated in the U.S.

What is the measles vaccine, and when would I have gotten it?

Measles is preventable with the combined Measles, Mumps, and Rubella (MMR) vaccine, and vaccination against measles has been part of routine childhood immunization for decades.

“Most Americans who went to school in America will have both MMR vaccines completed, and then should be protected against the measles,” Napa public health officer Dr. Christine Wu said.

There’s also a combined Measles, Mumps, Rubella and Varicella, or MMRV, vaccine, but it’s only licensed for use in children between ages 1 to 12 years old.

CDPH affirms that “MMR vaccines are very safe and effective,” and as with “any medicine, there can be side effects, but they are usually mild and go away on their own.”

The CDC recommends that everyone over 12 months of age be vaccinated against measles, with children receiving the first of two doses of the MMR vaccine between 12 to 15 months of age. The second dose is recommended between 4 to 6 years of age. This vaccine provides lifetime protection against measles, so if you got your MMR vaccine as a child, you’re considered up-to-date on your vaccine.

According to CDC data from the 2023-24 school year, California has a 96.2% vaccination rate against measles.

If I’m up-to-date on my measles vaccines, do I need a measles booster?

No. The CDC’s longtime advice says: If you had two doses of measles vaccine as a child according to the U.S. vaccination schedule, the CDC considers you “protected for life” and you “do not ever need a booster dose.”

In fact, said Wu, the second dose of your MMR vaccine is actually considered your booster “that provides a lifelong immunity.”

There are, however, two groups of older adults who received childhood measles vaccinations but who should still talk to their health care provider about possibly getting another vaccination:

People born between 1957 and 1969

If you are in this age group, which would make you between 56 and 68 years old today, it’s likely you only received one dose of the MMR vaccine and should consider getting a second dose, according to Bay Area health officers in 2025.

What if you were born before 1957?

According to the CDC, everyone born before this year is presumed to have immunity from measles from a previous infection, given how widespread the virus was during that period — although people in this age group who work in health care and who don’t have any written evidence of this immunity should get the MMR vaccine anyway.

People who received the ‘killed’ measles vaccine between 1963 and 1967

The “killed,” or inactivated, measles vaccine was an earlier formulation of the measles vaccine that was only used for this brief period in the 1960s, for fewer than one million people. Because it was found to be ineffective and replaced with the current live vaccine, people who know they received this particular version of the vaccine “should talk to their health care provider about getting revaccinated” with the MMR vaccine, according to the CDC.

“There is no harm in getting another dose of MMR vaccine if you may already be immune to measles (or mumps or rubella),” according to the CDC.

I don’t know if I’m vaccinated against measles. How can I check?

There’s no national organization that maintains Americans’ vaccination records. Ways that the CDC suggests to track down your own records include:

• Ask your parents or caregivers for records of your childhood immunizations (or look in saved documents from your childhood, like baby books).
• Consult a state immunization registry like the California Department of Public Health’s Digital Vaccine Record portal.
• Ask your doctor or public health clinic, but remember that these records may only be stored for a limited time.

The CDC has a guide to tracking down your vaccination records.

Another reason to check your vaccination status if you’re unsure: Possessing documentation of your vaccination status “can help you avoid being quarantined if you are exposed,” according to a 2025 advisory from Bay Area health officers.

And if you can’t find any sign that you or your family have received a measles vaccine?

“Teenagers and adults with no evidence of immunity should be vaccinated right away,” they added — something the CDC echoes.

Your health provider can also order “a simple blood test,” said Wu, to check whether or not you are immune from measles, either from vaccination or from a childhood infection.

If I’m vaccinated, am I still at risk of getting measles?

Six years of living with COVID-19 have taught us that being vaccinated against a virus doesn’t necessarily mean you won’t get infected with that virus. The COVID-19 vaccine, for example, does somewhat reduce your chances of being infected — although the CDC said that “protection against infection tends to be modest and sometimes short-lived” — but it also means you’re much less likely to get severely ill if you do get infected.

However, the measles vaccine is incredibly effective at protecting against infections, the CDC said, and two doses of measles vaccine are “about 97% effective” at preventing measles if you’re exposed. (One dose is “about 93% effective.”)

As for why “about three out of 100” people vaccinated against measles will still get measles after exposure — also known as breakthrough cases — the CDC said that experts “aren’t sure why” and that this could be due to the responsiveness of an individual’s immune system to the vaccine.

“But the good news is, fully vaccinated people who get measles seem more likely to have a milder illness,” the CDC said — and fully vaccinated people “seem also less likely to spread the disease to other people.”

Where can I find a measles vaccine in the Bay Area?

If you have health insurance, the CDC’s recommendation of these shots means that your insurer should cover the costs. The CDC’s recent changes to the U.S. vaccine schedule for children under the leadership of U.S. Health and Human Services Secretary Robert F. Kennedy Jr. do not affect the agency’s recommendation of the MMR vaccine or insurance coverage of these shots. In 2025, Kennedy dissolved the CDC’s Advisory Committee on Immunization Practices and replaced its members with a number of doctors and researchers who have repeatedly questioned, without evidence, the safety of commonly used vaccines and ingredients.

You can find appointments for an MMR vaccine at:

• Your regular health care provider.
• A local pharmacy like CVS or Walgreens.
• vaccines.gov, the federal government’s vaccine locator.
• myturn.ca.gov, the state’s vaccine locator.

For those without insurance: Uninsured children ages 18 and under can get free DTaP vaccines — and other no-cost immunizations — as part of the Vaccines for Children Program. People without insurance can get the MMR vaccine at a lower cost — or even free if they qualify for the Vaccines for Adults Program — from several providers and community clinics around the Bay Area, including:

• San Francisco Department of Public Health’s AITC clinic.
• Contra Costa Public Health Immunization Clinics.
• Alameda County Immunization Clinics.

KQED’s Samantha Kennedy and Nisa Khan contributed to this report.