Measles returns to SF

San Francisco confirmed its first measles case since 2019 after an unvaccinated infant became infected following international travel. (sf.gov) The San Francisco Department of Public Health said the case was confirmed April 13, 2026, in an infant younger than 12 months who became infectious after returning home. The child is recovering, and the city is tracing contacts who may have been exposed. (sf.gov) State health officials said California had reported 39 confirmed measles cases as of noon on April 13, spread across January, February, March, and April. San Francisco’s advisory, published April 15, put the statewide count at at least 40 after adding the city’s case. (cdph.ca.gov) (sf.gov) That is already more than California recorded in all of 2025, when Marin County Public Health said the state logged 25 cases. The California Department of Public Health says the last statewide outbreak before 2026 was a five-case cluster in early 2020. (marinhhs.org) (cdph.ca.gov) Health officials are focusing on infants and travelers because measles is often imported through travel and can spread before the rash appears. California told clinicians in February that people with measles are contagious from four days before rash onset through four days after. (cdph.ca.gov) The Bay Area is not seeing the same pattern everywhere. Santa Clara County confirmed a travel-linked measles case on March 2, while Marin County said on March 23 that it still had no local cases but was monitoring Bay Area activity. (publichealthproviders.santaclaracounty.gov) (marinhhs.org) Vaccination coverage in California schools remains high on paper, though uneven by county. The state reported 96.1% measles, mumps and rubella coverage among kindergartners in 2024-25, while warning that 26% of counties were below the 95% level often used to prevent transmission. (cdph.ca.gov) Measles spreads through the air, can linger for up to two hours after an infected person leaves, and infects roughly 90% of unvaccinated people who are exposed, according to the state. Two doses of the measles, mumps and rubella vaccine provide 97% protection. (cdph.ca.gov) San Francisco is telling clinicians to isolate suspected cases immediately and asking families to check vaccine records before travel. The city said infants ages 6 to 11 months should get an early measles, mumps and rubella dose before international trips, then return to the regular schedule after age 12 months. (sf.gov)