Kindergarten Vaccination Coverage Slips Again: The 2021–22 School Year

State and local school vaccination requirements protect students and communities from vaccine-preventable diseases. Each year state and local immunization programs, working with education departments and school nurses, report how many kindergartners are vaccinated or exempt, and CDC turns the counts into state and national estimates. This report covers the 2021–22 school year, the second affected by the COVID-19 pandemic.

Coverage fell again

National coverage among kindergartners was:

Coverage fell 0.8–0.9 percentage points for every vaccine compared with 2020–21, and declined in most states. It had been 95% in 2019–20, when children were vaccinated before the pandemic, and about 94% in 2020–21. Alaska had the lowest coverage for every vaccine (76.1%–78.0%) and Mississippi the highest (at least 98.6%). MMR coverage in 2020–21 and 2021–22 was the lowest reported since 2013–14, and for the second year in a row it missed the Healthy People 2030 target of 95%. At 93.0%, approximately 250,000 kindergartners may not be protected against measles.

National coverage with 2 doses of MMR vaccine among kindergartners, 2013–14 to 2021–22. CDC, MMWR.

Exemptions low, but more children behind

• Exemptions: 2.6% of kindergartners had an exemption from at least one required vaccine (0.2% medical, 2.3% nonmedical), up from 2.2% the year before, and up in 38 states and D.C. They ranged from 0.1% in Mississippi, New York and West Virginia to 9.8% in Idaho.
• Behind without an exemption: another 4.4% were not up to date with MMR and had no exemption — a share that rose in most states. Many such children attend school during a grace period or on provisional enrollment, policies that were widened in 2020–21 and, to a lesser degree, in 2021–22. In the 27 states reporting it, 2.4% of kindergartners were in a grace period or provisionally enrolled (from under 0.1% in Hawaii to 8.5% in Wisconsin).

That second group is where coverage could be recovered. Of the 35 states and D.C. with MMR coverage below 95%, all but four could reach 95% if every nonexempt child without documented vaccination were vaccinated.

Potentially achievable MMR coverage among kindergartners, by state, 2021–22. CDC, MMWR.

The pandemic's lingering effects

Although schools had nearly all returned to in-person classes, 23 states reported COVID-19 effects on data collection — lower response from schools, extensions and delays, incomplete data — and 30 reported lingering effects on coverage itself, mostly fewer vaccination appointments and extended grace periods or provisional enrollment.

The data

Forty-nine states (all but Montana) and D.C. reported. Of 3,835,130 kindergartners enrolled, 3,536,546 (92.2%) were surveyed for vaccination, 3,686,775 (96.1%) for exemptions and 2,527,578 (65.9%) for grace period or provisional status. Requirements differ by state — in which vaccines, how many doses and what documentation count — and eight states counted a child as up to date only with every required vaccine. Some estimates are lower bounds, some schools and homeschooled children may be missed, and documentation can be inaccurate.

What helps

Pockets of undervaccinated children inside well-vaccinated areas can spark outbreaks. Programs can use school assessments and immunization information systems to find schools and communities with low coverage. Enforcing school requirements, school-based vaccination clinics, reminder and recall systems, and follow-up by school nurses with undervaccinated students all improve coverage, as do catch-up campaigns.

Sources

• Seither R, Calhoun K, Yusuf OB, et al. "Vaccination Coverage with Selected Vaccines and Exemption Rates Among Children in Kindergarten — United States, 2021–22 School Year." MMWR 72(2), as corrected by the published erratum. CDC.