Kindergarten vaccination rates across the United States experienced another slight decline last year, while the proportion of children with vaccine exemptions reached an unprecedented high, according to federal data released Monday. The percentage of children exempted from vaccine requirements increased to 4.2%, up from 3.6% the previous year, representing an estimated 155,000 children nationally during the 2025-2026 school year.
This marks the fourth consecutive year the national average exemption rate has set a new record, with the majority of these exemptions attributed to parents withholding shots for nonmedical reasons. Exemptions saw an increase in 41 states and the District of Columbia.
Experts attribute this trend primarily to what they describe as chaos and confusion within vaccination recommendation systems over the past year or so. U.S. Health Secretary Robert F. Kennedy Jr., who was a prominent figure in the antivaccine movement before his appointment, and other federal officials have repeatedly attempted to revise and reduce childhood vaccination guidance. Earlier this month, President Donald Trump advocated for revamped childhood vaccination recommendations that promote his theory suggesting childhood shots should be spaced out into separate medical visits.
Dr. James Campbell of the American Academy of Pediatrics noted that the root cause of the decline is the turmoil caused by federal health officials. The Centers for Disease Control and Prevention (CDC) reported that 92.4% of 2025-26 kindergarteners received their required measles-mumps-rubella shots, a slight decrease from the prior year. Before the COVID-19 pandemic, this vaccination rate stood at 95%, a level considered sufficient to prevent a single infection from triggering a disease cluster or outbreak.
Vaccination rates also declined for polio, the combination diphtheria, tetanus, and pertussis shot, and the first dose of the chickenpox vaccine. The rate for hepatitis B protection remained stable. Campbell, a University of Maryland researcher and chair of the AAP’s infectious diseases committee, indicated that it would take a few years for recent federal efforts to alter infant hepatitis B vaccine recommendations to reflect in kindergarten vaccination rates.
These vaccination figures emerge as the U.S. faces its most severe year for measles since 1991. Campbell stated that the numbers suggest over a quarter of a million children entering kindergarten are susceptible to measles. He added that these at-risk children are not uniformly distributed, with higher concentrations of unvaccinated children in certain areas, which explains the varying intensity of measles waves.
Public health officials typically emphasize the benefits of vaccines during this period. North Carolina Health and Human Services Secretary Dev Sangvai stated that the back-to-school season serves as an important reminder that protecting children’s health is a shared responsibility and goal, and that vaccines help keep children and teens healthy and in the classroom.
In previous years, the CDC published vaccination coverage data in its flagship publication, the Morbidity and Mortality Weekly Report, with officials typically discussing trends and stressing the importance of vaccinations. However, since the Trump administration took office early last year, the agency has posted the data online. This year, the agency issued a three-sentence statement noting a small decline in vaccination coverage among children entering kindergarten and encouraging parents to discuss vaccination options with their doctors.
Public health officials focus on kindergarten vaccination rates because schools can be environments where germs spread rapidly, potentially leading to community outbreaks. For many years, these rates were high due to school attendance mandates requiring key vaccinations. All U.S. states and territories mandate that children attending childcare centers and schools be vaccinated against various diseases, including measles, mumps, polio, tetanus, whooping cough, and chickenpox. All states permit exemptions for children with medical conditions preventing certain vaccines, and most also allow exemptions for religious or other nonmedical reasons.
Over the last decade, the percentage of kindergartners with medical exemptions has remained consistent at approximately 0.2%. However, the percentage with nonmedical exemptions has increased. According to CDC data, 17.5% of kindergartners in Idaho had an exemption to one or more vaccines in the last school year, while fewer than 0.5% did in Connecticut.
