Vaccine coverage among US kindergarteners declines again

The percentage of kindergarteners who had received certain routine childhood immunizations declined again last school year, CDC researchers reported Thursday.

According to a study published in MMWR, during the 2021-2022 school year, the proportion of kindergarteners in the United States who had received four vaccines — shots against measles, mumps, and rubella (MMR); diphtheria, tetanus, and acellular pertussis; poliovirus; and varicella — dropped to approximately 93%.

That was down from 94% in the 2020-2021 school year, which was a decline from 95% reported during the 2019-2020 school year.

The decline means that at least 250,000 children are potentially unprotected against measles, according to the researchers, which could lead to outbreaks.

Georgina Peacock, MD, MPH, FAAP, director of the CDC’s Immunization Services Division, said in a call with reporters that MMR vaccination coverage for kindergarteners was at its “lowest in over a decade.”

However, a second study published in MMWR did not identify any decreases in national vaccination coverage by age 24 months associated with the COVID-19 pandemic, although coverage with the combined seven-vaccine series for children living below the federal poverty level or in rural areas decreased by 4 to 5 percentage points, researchers reported.

Children without insurance were eight times more likely than insured children to be unvaccinated by their second birthday.

“While we continue to monitor the impact of the pandemic, we are encouraged that this report did not identify a national drop in vaccination coverage among children aged 24 months at the beginning of the pandemic,” Peacock said. “However, these new findings also revealed persistent — and in some cases — widening disparities in coverage.”

The findings “add to previous research that highlights the impact of the COVID 19 pandemic on routine childhood vaccinations, as well as ongoing disparities in coverage,” Peacock said.

Peacock noted the recent measles outbreaks in Ohio and discovery of poliovirus in New York.

“These outbreaks were preventable,” Peacock said. “The best way to prevent these diseases and their devastating impact on children is through vaccination. Although overall routine vaccination remains high, these recent outbreaks and data underscore that under- and uninsured children are at risk for serious illness. We believe there are multiple reasons for the declines in vaccination, and we are engaging in numerous strategies to address them.”

Sean T. O’Leary, MD, FAAP, chair of AAP’s committee on infectious diseases, also spoke during the teleconference.

“For many parents today, the diseases we vaccinate children against are theoretical. They haven't seen them because vaccines have worked so well over the decades,” O’Leary said. “Personally, as a pediatrician who specializes in infectious diseases, I take care of a lot of hospitalized children. Believe me, as much as we try to make the experience as painless as possible, it's never fun to have your child hospitalized. Many of these hospitalizations can be prevented by the simple, safe step of keeping your child up to date on recommended vaccinations.”

References:

Hill HA, et al. MMWR Morb Mortal Wkly Rep. 2023;doi:10.15585/mmwr.mm7202a3.

Seither R, et al. MMWR Morb Mortal Wkly Rep. 2023;doi:10.15585/mmwr.mm7202a2.