Health Advisory: Measles Case Confirmed in San Francisco

April 15, 2026

Situational Update

On April 13, SFDPH confirmed a case of measles in an unvaccinated infant under the age of 12 months. The infant was exposed to measles while traveling internationally and became infectious after returning to San Francisco. SFDPH is conducting a contact investigation to identify susceptible individuals who may have been exposed to measles in order to prevent further spread. This is the first case of measles in San Francisco since 2019. With this case, at least 40 confirmed measles cases have now been reported in California in 2026.

Actions Requested of SF Clinicians

Consider the diagnosis of measles in patients with fever, rash, and other measles symptoms, such as cough, coryza, and conjunctivitis, and find out about vaccination history and possible exposures, such as international travel.
- Immediately isolate patients with suspected measles, using airborne precautions if available, to prevent nosocomial measles exposures.
- If possible, triage patients with fever and rash even before seeing a provider.
Immediately call SFDPH 24/7 at the number below to report patients with suspected measles. SFDPH will arrange for expedited laboratory testing if indicated.
- Collect throat (preferred) or NP swab and urine for PCR testing.
Ensure all patients planning to travel internationally are fully vaccinated against measles.
- Infants 6–11 months old should receive an early dose of MMR prior to traveling. They will then need to be vaccinated again according to the normal schedule after 12 months of age.
- Children 12 months and older and adults born in 1957 or later should have documentation of 2 doses of MMR at least 28 days apart.

Resources

CDPH: CDPH measles webpage and February 4, 2026 measles health alert (CAHAN)

SFDPH: sf.gov/measles

Program Contact Information

Communicable Disease Branch
Population Health Division | San Francisco Department of Public Health
Tel: (628) 217-6100 | Email: cdcontrol@sfdph.org