Study: COVID-19 vaccine effectiveness in children varies by age, variant

Editor's Note

According to a multi-institutional study from the Centers for Disease Control and Prevention, titled “Effectiveness of 2-Dose BNT162b2 (Pfizer BioNTech) mRNA Vaccine in Preventing SARS-CoV-2 Infection Among Children Aged 5–11 Years and Adolescents Aged 12–15 Years” and published on March 18, two doses of the Pfizer-BioNTech COVID-19 vaccine were more effective in reducing infections against the Delta variant than Omicron, JAMA Network April 26 reports.

The study also revealed a greater protection post-vaccination in adolescents than in younger age groups. The study encompassed weekly COVID-19 testing on 1,364 individuals aged 5 to 15 years between July 25, 2021, and February 12, 2022, at sites in Arizona, Florida, Texas, and Utah.

JAMA listed the following findings:

• 2 vaccine doses were 31% effective against the Omicron variant among children aged 5 to 11 years
• 2 doses were 59% effective against Omicron among adolescents aged 12 to 15 years
• 2 doses were 87% effective against the Delta variant among adolescents.

The study also showed differences in the effect of the variants in unvaccinated youth, JAMA noted. Even with the slight variation in efficacy, the study authors still recommend that all children and adolescents receive COVID-19 vaccines as recommended.