U.S. kindergarten vaccination coverage fell 0.1% during the 2025-2026 school year, continuing a downward trend that has seen declines every year except one since the onset of COVID-19, according to data from the U.S. Centers for Disease Control and Prevention released on Monday.
Coverage ranged from 92% for the diphtheria, tetanus and acellular pertussis vaccine (DTaP) to 92.4% for the measles, mumps and rubella vaccine (MMR) and the polio vaccine, the CDC said.
The CDC said coverage for the MMR, DTaP, polio and varicella vaccines decreased in more than half the states from the previous year.
"It's continuing a long trend in the wrong direction," said John Grabenstein, a pharmacist who previously ran the Department of Defense's vaccine programs for troops and their families.
"It's not like a tipping point," Grabenstein said. "If trends hold, we'll have twice as many measles cases this year as we did the previous year. It's just going to keep getting worse."
This is the first data for kindergartners who have enrolled into U.S. schools since Robert F. Kennedy Jr., a noted vaccine skeptic, became the country's health secretary.
U.S. President Donald Trump signed an executive order last week calling for fewer childhood vaccinations by limiting the inoculation schedule to 11 immunizations. The order also recommended splitting the measles, mumps and rubella vaccine into three shots taken at separate visits.
Exemptions from one or more vaccines among kindergartners in the U.S. increased to 4.2% during the 2025-2026 school year from 3.6% in the previous school year, the CDC said.
Exemptions rose in 41 states and Washington, D.C. Of these, 24 states reported exemptions exceeding 5%.
Jen Kates, senior vice president of KFF, a health policy research group, said that although overall the average coverage has fallen, it was being driven by large drops in certain areas of the country, and it is in these pockets of low protection where outbreaks occur.
She said it has a knock-on effect for the whole country. "That's why we're seeing the greatest measles outbreak in the United States that we've seen in decades."
The number of kindergartners attending school without documentation of completing the MMR vaccine series was about 280,000 during the 2025-2026 school year, according to the CDC.
Some states fared better than others when it came to the combined MMR shot. Texas, which experienced a severe measles outbreak last year just before this kindergartner data was collected, saw MMR rates stay the same year over year at 93.2%, an improvement compared to previous time periods.
California, meanwhile, dropped more than any year since the COVID-19 pandemic, down 0.4 points to 95.7%.
According to the CDC data, the states with the highest vaccination rates for the MMR vaccine were West Virginia, Connecticut, Maine, New York and Mississippi. The states with the lowest rates were Idaho, Wisconsin, Minnesota, Utah and Arizona.
With 2,566 confirmed measles infections so far this year, the U.S. is experiencing the highest number of cases in more than 35 years. The rise in cases coincides with a steady decline in childhood MMR vaccination rates since the start of the COVID-19 pandemic.
According to the CDC, at least 95% of people need two doses of the measles vaccine to help prevent outbreaks and keep communities safe.
