SF Gate Seventeen cases of measles have been reported across California since the start of 2026, including the state’s first outbreak of the highly contagious virus since 2020. The California Department of Public Health issued a health alert on Monday, warning residents of the ongoing transmission as cases emerge across multiple counties. Eight of those cases are part of a related outbreak in Shasta County, according to the department, making it the largest cluster identified so far. All individuals involved were either unvaccinated or had an unknown vaccination history.
As of Feb. 9, confirmed cases have also been reported in Los Angeles, Orange, San Bernardino and Riverside counties. Public health officials are also investigating additional suspected cases.
Two people with measles visited Disneyland on Jan. 22 and Jan. 28 while infectious, prompting state and local health officials to work with the park to notify potentially exposed employees and visitors, the CDPH said, adding that anyone who visited the park on those dates and later developed symptoms should contact a health provider.