COVID vaccination in 5- to 11-year-olds: What does the science say?

illustration of school-age children with coronavirus particles
Vaccination cut hospitalizations by 68 percent in this age group during the Omicron surge, a study finds. (Images: Adobe Stock. Illustration: Sebastian Stankiewicz/Boston Children's Hospital)

The Pfizer–BioNTech COVID-19 vaccine was approved for children ages 5 to 11 in October, but many parents have been hesitant to get them vaccinated. A national study in The New England Journal of Medicine provides reassuring data, showing that the vaccine strongly protected this age group against severe COVID-19.

Dr. Adrienne Randolph at Boston Children’s and colleagues at the Centers for Disease Control and Prevention looked back at hospital admissions for COVID-19 and other reasons at 31 children’s hospitals across the U.S. They tapped data from the Overcoming COVID-19 Network, which Dr. Randolph launched in 2020.

Of 267 children ages 5 to 11 who were hospitalized with COVID-19, 92 percent were unvaccinated. Sixteen percent were critically ill, needing life-supporting measures such as intubation. The team estimates that full vaccination (two doses) reduced the risk of hospitalization by more than two-thirds during Omicron.

“The numbers of children were too small for us to evaluate the vaccine’s effectiveness against different levels of COVID-19 severity, such as critical illness. And we could only assess benefits during the Omicron wave since the vaccine was not yet available during Delta,” says Dr. Randolph. “But the evidence shows that vaccination substantially reduces the risk of severe disease requiring hospitalization in 5- to 11-year-olds.”

Vaccine protection confirmed in adolescents

The study also confirms that vaccination reduced the risk of COVID-19 hospitalization in adolescents ages 12 to 18 and protected strongly against severe illness, in line with research earlier this year. Of adolescents hospitalized with COVID-19, 87 percent were unvaccinated. Of the 27 percent who had critical illness, 93 percent were unvaccinated. Two children passed away.

Adolescents became eligible for COVID vaccines starting in December 2020, so the team was able to look at vaccine efficacy during both the Delta and Omicron surges. Efficacy against hospitalization fell from 92 percent during Delta to 40 percent during Omicron. But efficacy against critical illness (requiring life support) held more steady: 96 percent during the Delta period and 79 percent during Omicron.

“Adolescents were less protected against hospitalization with Omicron versus Delta,” Dr. Randolph says. “But the vaccine strongly protected against critical illness from both variants.”

What are COVID vaccination rates among kids now?

According to data from the CDC, only 27 percent of 5- to 11-year-olds and just 57 percent of 12- to 17-year-olds were fully vaccinated as of March 23, 2022. Dr. Randolph hopes the latest findings will change some minds.

“Parents naturally want to protect their kids, so we hope our findings will encourage them to vaccinate them,” says Dr. Randolph. “Severe infections in childhood can have long-term consequences, and the benefits of COVID-19 vaccination clearly outweigh the risks.”

Learn more about COVID-19 research at Boston Children’s.

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