Vaccination rates among kindergarteners dipped below the public health target of 95% during the 2020-2021 school year, the CDC said.
National coverage was 93.9% for the two-dose measles, mumps, and rubella (MMR) vaccine, 93.6% for the state-required number of doses of the diphtheria, tetanus, and acellular pertussis (DTaP) vaccine, and 93.6% for the state-required number of doses of the varicella vaccine, reported Ranee Seither, MPH, of the CDC's National Center for Immunization and Respiratory Diseases, and colleagues in the .
Though coverage is still viewed as high, with only a 1-percentage point drop in routine vaccination rates for 2020-2021 compared with 2019-2020, CDC's experts still see a cause for concern.
"This means that there's 35,000 more children in the United States during this time period without documentation of complete vaccination against common diseases," said Georgina Peacock, MD, MPH, acting director of the CDC's Immunization Services Division, during a press call.
Another red flag is the fact that 400,000 fewer children than expected entered kindergarten in 2020-2021, noted Peacock, who was not involved in the report. Enrollment reported across 48 states was 10% lower than that reported in 2019-2020. "So, we don't have information on whether they're vaccinated or not," she pointed out.
Seither and colleagues tracked school entry vaccination data among kindergartners in 47 states and the District of Columbia (excluding Alaska, Illinois, and Virginia), as well as vaccine exemptions in 48 states and D.C.
They also looked at "provisional enrollment" policies, which allow students to go to school without completing required vaccinations or with an exemption while finishing the vaccination schedule, and "grace periods," which allow children to attend school for a certain number of days without proof of complete vaccination or exemption.
More than half of all reporting states observed an increase in the number of students requiring a grace period or provisional enrollment, which became more popular due to COVID-19-related disruptions, said Shannon Stokley, DrPH, deputy director of the Immunization Services Division, during the call.
The number of kindergarteners with an exemption to at least one vaccine continued to be "low," at approximately 2%, she noted, but almost 4% were not up date on their MMR vaccinations and lacked exemptions.
For the states whose MMR coverage fell below 95%, all but two could potentially have achieved coverage of 95% -- the Healthy People 2030 target -- if all of the non-exempt kindergarteners categorized as being in a grace period, provisionally enrolled, or out of compliance were vaccinated.
State officials blamed the decline in vaccination coverage on pandemic-related factors, including reduced access to well-child visits and reluctance by parents to schedule such appointments. They also pointed out that there were fewer staff members to conduct vaccination coverage assessments and report vaccination activities, and that fewer parents submitted documentation of vaccination.
"Overall, today's findings support previous data showing a concerning decline in childhood immunizations that began in March 2020," Stokley said, including the 10% drop in orders for distribution of routine vaccines from the CDC's Vaccines for Children Program, which is responsible for vaccinating nearly half of all children in the U.S.
Asked whether hesitancy around COVID-19 vaccines influenced vaccination coverage among kindergarteners, Peacock explained that the data reflected a time period before these vaccines were even available and reaffirmed the view shared by states that the decline in vaccination stemmed from COVID-related disruptions.
Peacock noted that she is optimistic that parents and healthcare providers can still recover lost ground, by rescheduling missed well-child visits or vaccine-only appointments, and flagging medical records for those behind on vaccinations. Schools can also help by issuing reminders to parents of children behind on their vaccines.
"With most schools back to in-person learning, implementing vaccination policies and following up with under-vaccinated students is critical to maintain the high coverage needed to protect children against vaccine-preventable diseases," she said.
Seither and colleagues noted that data collection methods may have failed to accurately measure vaccination status, with certain schools and students being overlooked, such as those who are home-schooled.
In addition, the pandemic limited "the amount and quality of student vaccination data" collected and reported by local health departments, due to school closures and the shift to virtual classes, relaxed vaccination requirements among states, and health department staff being reassigned to pandemic response activities, they said.
Primary Source
Morbidity and Mortality Weekly Report
Seither R, et al "Vaccination coverage with selected vaccines and exemption rates among children in kindergarten -- United States 2020-21 school year" MMWR 2022; DOI: 10.15585/mmwr.mm7116a1.