U.S. kindergarten vaccine exemptions hit record 4.2% as rates slip
Why it matters: MMR coverage fell to 92.4%, below the 95% level that helps prevent measles outbreaks.
U.S. kindergarten vaccination rates edged down again in the 2025-26 school year while exemptions climbed to a record high, according to federal data posted Monday. The exemption rate rose to 4.2% from 3.6% a year earlier, equal to about 155,000 children nationwide. CDC data showed 92.4% of kindergartners received the measles-mumps-rubella shot, down slightly from the prior year and below the 95% threshold that helps stop outbreaks. Rates also fell for polio, diphtheria-tetanus-pertussis and the first chickenpox dose. The figures came as the United States faces its worst measles year since 1991, with experts warning that clusters of unvaccinated children can fuel outbreaks.