California Detects Measles in Wastewater as 74 Cases Mark Biggest Outbreak in 7 Years
Updated
Updated · Inkl · Jun 7
California Detects Measles in Wastewater as 74 Cases Mark Biggest Outbreak in 7 Years
3 articles · Updated · Inkl · Jun 7
Summary
Merced County found measles virus in routine wastewater testing, a signal health officials say could point to undetected community spread even though no local human cases have been confirmed.
California has recorded 74 confirmed measles cases across seven counties, far above the 25 reported in all of 2025 and the state's largest outbreak in seven years.
About 96% of infected people were unvaccinated or had unknown vaccination status, and officials say pockets of low coverage are undermining the state's roughly 95% kindergarten vaccination rate.
Measles can infect up to 9 in 10 unvaccinated people exposed in an enclosed space and linger in the air for up to two hours, making outbreaks hard to contain.
State officials are urging residents to verify MMR vaccination records and ignore online claims that vitamin A or cod liver oil can replace the vaccine.