US Kindergarten MMR Coverage Slides Below Herd Immunity Threshold Amid Record Exemption Rates

CDC figures indicate national measles-mumps-rubella (MMR) vaccination coverage among kindergartners dropped from 95.2 percent in 2019-2020 to 92.4 percent in 2025-2026.

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For decades, the United States kept measles at bay largely by ensuring enough children received vaccinations before ever entering a kindergarten classroom. That margin is now eroding.

New federal data show kindergarten vaccination rates continuing a multiyear slide even as parents claim vaccine exemptions at the highest rate ever recorded. This trend plays out against the backdrop of the country’s worst measles year since 1991. “We should be worried, because we’re already seeing the consequences of declines in vaccination,” Jeanne Marrazzo, chief executive officer of the Infectious Diseases Society of America, told CIDRAP News. “All you have to do is look at measles.”

The figures come from the CDC’s SchoolVaxView platform, which tallies immunization and exemption rates among kindergartners using state health department reports from the prior school year each August. For the 2025-2026 school year, national coverage for the measles-mumps-rubella (MMR) vaccine fell to 92.4 percent, down from 95.2 percent as recently as the 2019-2020 school year and below the 95 percent threshold epidemiologists say is needed to sustain herd immunity against measles. Vaccine exemptions, meanwhile, climbed to a record 4.2 percent nationally—about 157,000 children—with non-medical exemptions alone more than doubling since the 2020-2021 school year.

What the Data Shows: Declining Coverage and Rising Exemptions Over Six Years

By the Numbers

• National MMR coverage among kindergartners has fallen from 95.2 percent in 2019-2020 to 92.4 percent in 2025-2026, according to the CDC—six straight school years below the 95 percent herd immunity threshold.
• The national kindergarten vaccine exemption rate has climbed from 2.2 percent in 2020-2021 to a record 4.2 percent in 2025-2026—about 157,000 children.
• Only 10 states met the 95 percent MMR coverage threshold considered necessary to sustain measles herd immunity in 2025-2026.
• Idaho’s vaccine exemption rate for non-medical reasons reached 17 percent in 2025-2026, the highest of any state and roughly quadruple the national average.

MMR coverage first slipped from 95.2 percent in 2019-2020 to 93.9 percent the following year, then declined in all but one of the next five school years; vaccine exemptions, after an initial pandemic-year dip, rose every year over the same stretch. An estimated 280,000 kindergartners started the 2025-2026 school year without documentation of a completed MMR series, according to the CDC.

Why It Matters: Immunity Gaps Are Fueling the Current Measles Surge

That national decline is not evenly distributed. Idaho’s vaccine exemption rate for non-medical reasons—17 percent in 2025-2026—is the country’s highest and roughly quadruple the national average, followed by Utah, Oregon, Arizona, Nevada, Alaska, and North Dakota, each at or above eight percent; 24 states now exceed a five percent overall exemption rate.

In a statement, Andrew Racine, president of the American Academy of Pediatrics, said that “for some diseases like measles, even a small decrease in vaccination rates can lead to more outbreaks of disease,” because community immunity requires more than 95 percent of susceptible individuals to be immunized. The pattern lines up with 2026’s measles resurgence, already the worst the US has recorded since 1991, with 3,471 confirmed cases as of September 17.

Unlike in past cycles, when the CDC published the kindergarten data with an analysis in its Morbidity and Mortality Weekly Report, the agency this year issued only a three-sentence statement saying overall vaccination rates “remained high” and encouraging parents to discuss vaccination options with their doctors. The abbreviated release drew a pointed reaction from Columbus Public Health Commissioner Mysheika Roberts, who, during a Big Cities Health Coalition press briefing, said it “just reaffirms that the CDC is no longer the trusted health agency that many of us were trained to rely on and to admire.” Sean O’Leary, the immunization schedule editor for the American Academy of Pediatrics’ Committee on Infectious Diseases, agreed. “I was absolutely not surprised either,” he said, though he stressed that “clearly that is coming from HHS [Department of Health and Human Services] leadership,” not from CDC scientists.

However, the figures are observational—they describe a trend, not its cause, and cannot on their own distinguish parental hesitancy from access barriers or from gaps in state reporting, since Montana has not reported coverage data since 2020-2021 and Kansas reported no coverage data this cycle. Left unaddressed, falling coverage could keep fueling outbreaks: “The less we see people taking up vaccinations, the more we’re going to see these cases accumulate,” Marrazzo said.

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