The proportion of U.S. kindergarteners exempted from required school vaccines climbed to a record 4.2% during the 2025-26 school year, federal data released Monday show, while overall immunization rates for several childhood diseases slipped. Public health experts warn that the trend could leave communities vulnerable to outbreaks of measles and other highly contagious illnesses.
Declining coverage and rising exemptions
The Centers for Disease Control and Prevention data indicate the exemption rate increased from 3.6% the prior year, representing an estimated 155,000 children nationwide who were not up to date with required vaccinations. The rise marks the fourth consecutive year the national exemption rate reached a new high and was driven primarily by parents seeking nonmedical exemptions.
Exemptions expanded in 41 states and the District of Columbia, according to the report. Officials said coverage fell for several routine childhood vaccines, including the measles-mumps-rubella (MMR) shot and vaccines for polio, diphtheria-tetanus-pertussis (DTaP), and the first dose of the chickenpox (varicella) vaccine. Protection against hepatitis B – which is typically administered shortly after birth – held steady.
Public health stakes and federal turmoil
The CDC reported that 92.4% of kindergartners in the 2025-26 school year received the required MMR doses, down slightly from the prior year and well below the pre-pandemic threshold of 95% that helps prevent sustained transmission. Health officials say that falling below that threshold increases the likelihood that a single imported case could spark a local outbreak.
Experts point to recent upheaval at the federal level as a factor in growing parental hesitancy. U.S. Health Secretary Robert F. Kennedy Jr., a former prominent voice in the antivaccine movement, has led federal health agencies since being appointed by President Donald Trump. In the past 18 months, Kennedy and other federal officials have pursued changes to childhood vaccine guidance, efforts that have included attempts to alter established recommendations.
“The root cause of this is primarily because there’s so much chaos and confusion in vaccination recommendation systems in the last year or so,” said Dr. James Campbell of the American Academy of Pediatrics.
Earlier this month, President Trump called for revised childhood vaccination recommendations that would promote spacing childhood shots into separate medical visits — a concept public health authorities have previously discredited as unnecessary from a safety and efficacy standpoint.
What fell and what held
The CDC highlighted several specific declines and one steady measure in its kindergarten assessment. The following table summarizes the agency's findings:
| Vaccine | Trend in 2025-26 |
|---|---|
| Measles-mumps-rubella (MMR) | Down to 92.4% |
| Polio | Declined |
| Diphtheria-tetanus-pertussis (DTaP) | Declined |
| Varicella (first dose) | Declined |
| Hepatitis B | Held steady |
Public-health specialists stress that even modest declines in coverage can open pathways for outbreaks, particularly for measles, which is among the most transmissible of vaccine-preventable diseases. The pre-pandemic MMR coverage of 95% is widely cited as the benchmark for community protection; levels below that make clusters more probable.
Policy and community consequences
The increase in nonmedical exemptions and the decline in vaccine coverage present dilemmas for states and school systems that must balance public health with parental rights. Some jurisdictions have tightened exemption rules in recent years, while others have seen rising numbers of parents seeking exemptions for philosophical or religious reasons.
- Record exemption rate: 4.2% (estimated 155,000 children)
- MMR coverage: 92.4%, below the 95% threshold
- Exemptions rose in 41 states and Washington, D.C.
Health authorities and pediatricians say clear, consistent federal guidance is critical to reverse the trend. Without it, they caution, communities could face renewed outbreaks that strain public-health resources and threaten the progress made against diseases once thought controlled.
