Routine childhood vaccine uptake among US kindergarteners in public and private schools declined to less than 93% in the 2023-24 school year, down from 95% in 2019-20 and 93% in 2022-23. At the same time, exemptions rose to a record 3.3%, up from 3.0% and 2.6%, respectively.
The findings, published today in Morbidity and Mortality Weekly Report (MMWR), come from data from 49 states and Washington, DC, reported to the Centers for Disease Control and Prevention (CDC).
Vaccination was considered a complete regimen of the measles, mumps, and rubella (MMR); diphtheria, tetanus, and acellular pertussis (DTaP); poliovirus; and varicella (VAR) vaccines.
"These results could indicate changes in attitudes toward routine vaccination transferring from hesitancy about COVID-19 vaccination, or toward any vaccine requirements arising from objections to COVID-19 vaccine mandates, as well as a potential for larger decreases in coverage or increases in exemptions," the CDC researchers wrote.
Coverage of each vaccine falls in most states
Compared with national vaccine coverage estimates on all reported vaccines for the 2019–20 and 2022–23 school years (95% and 93%, respectively), uptake fell below 93% in 2023–24, ranging from 92.3% for DTaP to 92.7% for MMR.
Uptake of the MMR, DTaP, polio, and VAR vaccines dropped in 35, 32, 33, and 36 states, respectively, compared with 2022–23. Two-dose national MMR coverage was 92.7% (range, 79.6% in Idaho to 98.3% in West Virginia), with coverage of 95% or higher in 11 states and under 90% in 14 states.
Five-dose DTaP coverage was 92.3% (range, 79.5% in Idaho to 98.4% in West Virginia), with coverage of 95% or higher in 12 states and under 90% in 15. Four-dose polio vaccine uptake was 92.6% (range, 80.1% in Idaho to 98.4% in West Virginia), with coverage of at least 95% in 12 states and less than 90% in 13.
Two-dose VAR vaccine uptake was 92.4% (range, 79.1% in Idaho to 99.7% in West Virginia), with 10 jurisdictions reporting at least 95% coverage and 15 having under 90% uptake. Coverage of each vaccine fell in most states in 2023-24 compared with 2022–23.
Exemptions rise in 41 states
Exemptions climbed to 3.3% (0.2% medical, 3.1% nonmedical), compared with 3.0% in 2022–23 and 2.6% in 2021–22 for at least one required vaccine (not limited to MMR, DTaP, polio, and VAR) in 2023–24 (range, less than 0.1% in West Virginia to 14.3% in Idaho). Exemptions rose in 41 states, with 14 reporting that over 5% of kindergartners had an exemption from at least one vaccine.
The decreases in coverage, combined with increases in exemptions, jeopardize reaching the Healthy People 2030 95% coverage of kindergartners with MMR target.
Nonmedical exemptions accounted for over 93% of exemptions and nearly all of the increase in national exemptions. Exemptions for one or more vaccines were higher than the national estimate of 3.3% in 30 states.
States with increases in exemptions were distributed across all US Department of Health and Human Services regions. Nationwide, 4.0% of kindergarteners were neither fully vaccinated with MMR nor exempt, and the potentially achievable coverage was 96.9%.
"The decreases in coverage, combined with increases in exemptions, jeopardize reaching the Healthy People 2030 95% coverage of kindergartners with MMR target," the authors wrote. "The number of jurisdictions with exemption rates >5%, making them unable to achieve ≥95% MMR coverage even if every nonexempt kindergartner was vaccinated, increased from two in 2020–21 to 14 in 2023–24. Approximately 280,000 (7.3%) kindergartners did not have documentation of 2 MMR doses and were potentially at risk for measles infection."
Provisional enrollment, or grace-period attendance, for kindergarten students who need more time to be vaccinated was 2.6% in 31 states reporting these data (range, 0.3% in Delaware to 8.0% in Arkansas).
Approaches to increase vaccination
Proven ways to increase vaccine uptake include enforcement of school vaccination requirements, school-based vaccination clinics, reminders and recalls, strong provider recommendations, and follow-up of undervaccinated students, the authors said.
Providers could educate parents specifically about the safety and effectiveness of vaccinations required for school entry, and the risks of delayed or incomplete vaccination or nonvaccination.
"Schools can also work with parents to avoid exemptions because of difficulty meeting vaccination requirements deadlines and share vaccination and exemption data as part of school vaccination assessments by state and local health departments," they wrote.
"While following evidence-based practices to improve vaccination coverage, providers could educate parents specifically about the safety and effectiveness of vaccinations required for school entry, and the risks of delayed or incomplete vaccination or nonvaccination to children, family members, classmates, and the community," they concluded.
