Vaccination rates for U.S. kindergarteners continued to decline last year, accompanied by a rise in exemptions to an unprecedented level. Recent federal data reveals that 4.2% of children were exempt from vaccination requirements, up from 3.6% the previous year. This translates to approximately 155,000 children nationally during the 2025-2026 school year. This marks the fourth consecutive year of increasing exemption rates, largely stemming from parents opting out for nonmedical reasons. Increases were noted across 41 states and the District of Columbia.
Health experts attribute these trends to disruptions caused by federal health officials. U.S. Health Secretary Robert F. Kennedy Jr., previously active in the antivaccine movement, assumed a leading federal health role under President Donald Trump. Over the past 18 months, he and others have attempted to modify childhood vaccination guidelines. Earlier in the month, Trump advocated for altered vaccination schedules that align with his discredited theory advocating spaced-out shots.
Dr. James Campbell of the American Academy of Pediatrics highlighted the confusion surrounding vaccination systems. ‘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,’ he stated.
Decreased Vaccination Rates for Key Diseases
The Centers for Disease Control and Prevention (CDC) reported a slight drop in the MMR (measles-mumps-rubella) vaccination rate among 2025-26 kindergarteners, falling to 92.4% from the previous year. Before the COVID-19 pandemic, the rate was at 95%, a threshold necessary to prevent outbreaks.
Vaccination rates also dropped for diseases such as polio, as well as for the diphtheria, tetanus, and pertussis combination shot, and the first chickenpox vaccine dose. However, the hepatitis B vaccination rate remained steady, as this is administered shortly after birth. Effects of recent policy changes on infant hepatitis B vaccination will appear in kindergartners’ rates in the future, according to Dr. Campbell.
This information is being released as the U.S. faces its worst measles outbreak since 1991, with over a quarter-million kindergartners vulnerable to measles. These unprotected children are dispersed unevenly, causing varying measles outbreak intensities.
Efforts to Promote Vaccination
The CDC data emerges as schools and health officials urge parents to vaccinate children as the school year begins. North Carolina Health and Human Services Secretary Dev Sangvai emphasized vaccination’s shared importance, stating, ‘Back-to-school season is an important reminder that protecting our children’s health is both a shared responsibility and a shared goal. Vaccines help keep our children and teens healthy and in the classroom.’
Traditionally, the CDC released vaccination data in its Morbidity and Mortality Weekly Report, accompanied by commentary on trends. However, since the Trump administration’s onset, these figures have been posted online with minimal statements, like this year’s brief note acknowledging a minor decline among kindergarten-aged children.
Exemption Trends and Legal Requirements
Kindergarten vaccination rates are closely monitored since schools can facilitate disease spread and community outbreaks. Historically, high rates were maintained due to mandates requiring several key vaccinations for school attendance.
All U.S. states and territories mandate vaccines for diseases like measles, mumps, polio, tetanus, whooping cough, and chickenpox for schoolchildren. Medical exemptions apply to children who cannot receive specific vaccines, and most states allow exemptions for religious or nonmedical reasons. Medical exemption rates have maintained steady at 0.2% over recent years, though nonmedical exemptions are rising.
CDC data highlights variations in nonmedical exemptions, with states like Idaho seeing 17.5% of kindergartners exempt, whereas less than 0.5% occurred in Connecticut.