For the fourth consecutive year, the share of American kindergartners exempt from required school vaccinations has climbed to a new record — and the geographic clusters of unvaccinated children now correspond almost perfectly with the locations of the nation's most active measles outbreaks in 2026.
CDC data confirmed that 3.6% of kindergartners in the 2024–25 school year had at least one vaccine exemption, up from 3.3% the previous year. That percentage translates to approximately 138,000 children entering the school system without documented vaccination against one or more diseases for which they are otherwise required to be immunized. The vast majority of those exemptions are nonmedical — granted for personal or religious reasons rather than genuine contraindications.
Where the Risk Is Highest
The national average obscures significantly worse conditions in specific states. According to the CDC, exemptions increased in 36 states and Washington, D.C. Seventeen states reported exemption rates exceeding 5%, with Idaho reaching 15.4% — the highest in the nation. When nearly one in six kindergartners enters school unvaccinated in a given state, the conditions for a sustained measles outbreak are not hypothetical; they are effectively guaranteed.
The MMR (measles, mumps, rubella) vaccine coverage rate among U.S. kindergartners fell to 92.5% in 2024–25, down from 92.7% the previous year — the fifth consecutive year below the federal Healthy People 2030 goal of 95% needed to prevent community transmission of measles. Nationally, approximately 286,000 kindergartners had no documented MMR vaccination. Polio, DTaP (diphtheria, tetanus, pertussis), and varicella coverage rates all declined as well.
| Vaccination Metric | 2024–25 Data |
| National vaccine exemption rate (kindergartners) | 3.6% (record high) |
| Previous record | 3.3% (2023–24) |
| Estimated children with exemptions | ~138,000 |
| States with exemption rates above 5% | 17 |
| Highest state exemption rate | Idaho — 15.4% |
| States where exemptions increased | 36 + Washington, D.C. |
| MMR coverage rate | 92.5% (below 95% herd immunity threshold) |
| Estimated unvaccinated kindergartners (MMR) | ~286,000 |
| Measles cases in 2025 | 1,333 (highest since 1992) |
| Pediatric measles deaths in 2025 | 2 |
| Whooping cough cases in 2024–25 | 35,000+ (six times 2023 rates) |
The Predictable Consequence: Record Measles and Rising Pertussis
The relationship between falling vaccination rates and rising outbreaks is not speculative — it is epidemiological cause and effect. Measles requires approximately 95% community vaccination coverage to prevent sustained transmission. The U.S. has been below that threshold nationally since at least the 2020–21 school year, and in states like Idaho, the gap is severe.
The 2025 measles case count of 1,333 cases — the highest since 1992 — included outbreaks in multiple states, with a particularly large cluster in West Texas linked primarily to unvaccinated children. Two pediatric deaths were recorded. In 2026, measles transmission continued in states with concentrated exemption clusters, with exposure reports at schools, churches, and public venues.
Whooping cough (pertussis) is following the same trajectory. More than 35,000 cases of whooping cough were reported in 2024–25 — roughly six times the rate of the prior year — in a direct reflection of falling DTaP vaccination rates among school-age children.
"That gap, combined with concentrated pockets of exemptions, is exactly how sustained outbreaks gain a foothold," said Dr. John Brownstein, an epidemiologist and ABC News medical contributor, in a statement to ABC News.
What Is Driving the Rise in Exemptions — and Who Is Responsible?
Most exemptions are being granted under state-level nonmedical exemption laws — laws that allow parents to opt out of required school vaccinations for personal, philosophical, or religious beliefs with minimal documentation. These laws vary significantly by state: some require only a signed form, while others require a physician's signature or annual renewal.
Public health messaging at the federal level has also shifted. The American Academy of Pediatrics has continued to call for eliminating nonmedical exemptions, but federal health authorities have, in recent months, emphasized personal choice in vaccination decisions — a shift that public health experts say has legitimized hesitancy and may be accelerating exemption rates going forward.
"Public health messaging has shifted in ways that place personal choice ahead of community protection," said Dr. Brownstein. "When federal leadership softens its stance on vaccination, it can accelerate hesitancy and legitimize nonmedical exemptions, further weakening population-level immunity."
AAP President Susan Kressly, M.D., FAAP, acknowledged the trend in a statement: "The good news is the vast majority of parents vaccinate their children. As pediatricians, we know that immunizing children helps them stay healthy, and when everyone can be immunized, it's harder for diseases to spread in our communities."
What Parents, Schools, and Local Health Officials Should Do
For parents: The MMR vaccine is highly effective, with two doses providing approximately 97% protection against measles. Children who are unvaccinated or have unknown vaccination status should be brought current before the fall 2026 school year.
For local health departments: The CDC's SchoolVaxView tool provides state- and district-level vaccination coverage data. Health departments in high-exemption states should be working with school districts now to identify clusters of under-vaccinated children before fall enrollment.
For school administrators: Schools with exemption rates significantly above the 95% threshold should have outbreak response plans in place, including protocols for rapid exclusion of unvaccinated students in the event of a confirmed measles case.
Measles is one of the most contagious viruses known; a single infectious person can infect up to 18 others in an unvaccinated population. Early identification of at-risk clusters and rapid response are the only tools available in the absence of pre-existing immunity.
Frequently Asked Questions
What does a 3.6% exemption rate actually mean?
It means approximately 138,000 kindergartners nationwide started school in 2024–25 without documentation of one or more required vaccines. In states like Idaho, the rate is dramatically higher — 15.4%, meaning roughly 1 in 7 kindergartners had an exemption.
Are my child's schools at risk?
It depends on local exemption rates and geographic clustering. The CDC's SchoolVaxView database allows parents and officials to look up vaccination coverage rates at the state and district level.
Why doesn't 92.5% MMR coverage prevent outbreaks?
Because measles requires approximately 95% community immunity to prevent sustained transmission, and in communities where exemptions are concentrated, local coverage may be far lower than the state average. A school district with 20% exemptions can sustain a measles outbreak regardless of what the statewide data says.
Are the vaccines safe?
Yes. The MMR, polio, DTaP, and varicella vaccines are among the most rigorously studied vaccines in history. Serious adverse reactions are extremely rare. The scientific consensus is clear that the benefits of vaccination far outweigh the risks.
What should I do if there's a measles case at my child's school?
Local health departments will notify exposed individuals and may exclude unvaccinated students and staff for 21 days after the last known exposure. Vaccinated children are not typically required to quarantine. Contact your local health department or pediatrician for guidance specific to your situation.
