S.F. infant diagnosed with measles, city's first case in seven years

San Francisco health officials on Wednesday reported the first case of measles in the city since 2019, in an unvaccinated infant who was infected during a recent international trip.

The infant, who is less than 1 year old, was exposed while traveling and became infectious after returning, according to the San Francisco Public Health Department, which confirmed the case on Monday. The infant is recovering at home, and other members of the household have been vaccinated.

*

RELATED: California hasn't seen measles numbers like this in years - and cases are still rising

Officials did not specify where the international travel was. It's not uncommon for unvaccinated U.S. residents to travel abroad to areas where measles is more prevalent, become infected there, and start showing symptoms when they return home.

Health officials are reaching out to the household's close contacts to prevent spread.

The first of the two-dose measles (MMR) vaccine series is recommended for children aged 12 to 15 months, and the second dose is recommended at 4 to 6 years. But infants 6 to 11 months can get the vaccine if they will be traveling internationally.

California and the U.S. are currently experiencing the largest number of measles cases in years, largely driven by declining vaccination rates. An ongoing outbreak in the Sacramento region, the largest outbreak in California so far in 2026, has resulted in 17 cases, mostly in unvaccinated children.

Copyright 2026 Tribune Content Agency. All Rights Reserved.

This story was originally published April 15, 2026 at 7:19 PM.