CDC Frets Over Further Dip in Kindergarten Vaccination Rates

Jake Remaly

January 13, 2023

The percentage of kindergarteners in the United States who have received routine vaccines to protect against illnesses such as measles, whooping cough, and polio has declined for 2 straight years, a new study has found.

Drops in vaccine coverage leave communities more susceptible to outbreaks of vaccine-preventable diseases, such as those that occurred in 2022, public health officials said.

Coverage for four vaccines ― against measles, mumps, and rubella (MMR); diphtheria, tetanus, and acellular pertussis (DTaP); poliovirus (polio); and varicella (chickenpox) ― among kindergarten students was about 95% in 2019–2020.

The rate fell to 94% the following year.

For the 2021–2022 school year, coverage dropped another point, to 93%, according to the report, published online January 12 in Morbidity and Mortality Weekly Report (MMWR).

The rate of vaccination overall remains high, but about 250,000 kindergarten students may not be protected against measles, the researchers estimate. Measles, which is highly infectious, can lead to serious illness and even death in children who have not been vaccinated against the virus.

"In 2022, two communities in the United States responded to outbreaks of measles where children have been hospitalized," Georgina Peacock, MD, MPH, director of the immunization services division of the Centers for Disease Control and Prevention (CDC), said in a media briefing about the report. "One community reported a case of paralytic polio in an unvaccinated person. These outbreaks were preventable. The best way to prevent these diseases and their devastating impact on children is through vaccination."

Exemptions Steady

For the new study, Ranee Seither, MPH, with the CDC's National Center for Immunization and Respiratory Diseases, and her colleagues analyzed data reported by states to estimate nationwide coverage for the four routine vaccines.

The number of students with exemptions remained low, at 2.6%, but another 3.9% who were without exemptions were not up to date with the MMR vaccine, the investigators report.

In a separate study, researchers found that vaccination coverage for 2-year-olds has increased. Approximately 70% of children were up to date with a seven-vaccine series by age 24 months. The coverage rate was higher for children born during 2018–2019 than for those born during 2016–2017.

Although the COVID-19 pandemic was not associated with decreased vaccination rates in this younger age group overall, coverage fell by 4 to 5 percentage points for children living below the poverty level or in rural areas, according to the study.

In addition, uninsured children were eight times more likely than those with private insurance to not be vaccinated by their second birthday, the researchers found.

Strategies to increase vaccination coverage include enforcing school vaccination requirements and holding vaccination clinics at schools, the CDC said.

"Providers should review children's histories and recommend needed vaccinations during every clinical encounter and address parental hesitancy to help reduce disparities and ensure that all children are protected from vaccine-preventable diseases," the agency said.

To that end, the agency launched an initiative this week called Let's RISE (Routine Immunizations on Schedule for Everyone) to provide clinicians with resources to help patients get on track with their immunizations.

Hundreds of Thousands Unprotected

MMR vaccination coverage for kindergartners is the lowest it has been in over a decade, Peacock noted. Decreased coverage for kindergarten students might be tied to pandemic-related disruptions in healthcare systems and schools, she said. School administrators and parents may have been less focused on routine vaccination paperwork amid the return to in-person learning, for instance.

Hesitancy about COVID vaccines could be affecting routine vaccinations. "That's something that we are watching very closely," Peacock said.

The two-point decrease in vaccination coverage "translates to hundreds of thousands of children starting school without being fully protected" against preventable diseases that can spread easily in classrooms, Sean O'Leary, MD, chair of the American Academy of Pediatrics' Committee on Infectious Diseases, said.

Despite the drop in coverage, O'Leary said he saw some encouraging signs in the data: Nonmedical exemptions for kindergarten students have not increased. And the vast majority of parents are still having their children vaccinated. At the same time, the reports highlight a need to address child poverty and improve vaccine access in rural areas, he said.

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