San Francisco Department of Public Health Confirms Measles Case in San Francisco Infant

SAN FRANCISCO – On the evening of April 13, the San Francisco Department of Public Health (SFDPH) confirmed a case of measles in an unvaccinated San Francisco infant under the age of 12 months. This is the first reported measles case in San Francisco since 2019. 

The infant was exposed to measles while traveling internationally, became infectious after returning, and is currently recovering at home. The infant’s household contacts all report being vaccinated. SFDPH is reaching out to close contacts outside of the home to prevent further spread of measles. At this time, the risk to the general public is low. If an individual has been identified as an exposed close contact, they may receive a phone call from SFDPH or the California Department of Public Health (CDPH).

Measles is a highly contagious virus that can cause serious illness and death. It spreads easily through the air when a person infectious with measles breathes, talks, coughs, or sneezes; the virus can linger in indoor air for up to an hour. Measles symptoms include fever, cough, runny nose, and conjunctivitis (pink eye), followed 2–4 days later by a rash. 

Complications of measles can include pneumonia (the most common cause of death from measles in children), encephalitis (swelling of the brain), and subacute sclerosing panencephalitis (SSPE), a rare but fatal progressive brain disease that develops years after recovery from initial illness.

The safe and highly effective measles, mumps, and rubella (MMR) vaccine offers the best protection against the virus. One dose of the MMR vaccine is 93 percent effective against measles, and two doses are 97 percent effective.

“It is incredibly important to get the MMR vaccine, as measles is one of the most infectious diseases in the world,” said San Francisco Health Officer Dr. Susan Philip. “If you and your family are traveling internationally, make sure everyone is up to date with the MMR vaccine and is aware of the symptoms of measles.”

The MMR vaccine is recommended for children aged 12–15 months, with a second dose administered between ages 4 and 6 years to complete the series. Importantly, infants 6–11 months of age are recommended to receive an early dose of measles vaccine if they will be traveling internationally, and all adults born in 1957 or later and children 12 months and older should ensure they have received two doses of MMR prior to international travel.

For questions about the MMR vaccine and immunization records, check with your health care provider or access your digital vaccine record. SFDPH will continue to closely monitor for measles activity.