For a study, researchers sought to assess the relationship between symptomatic infection and previous immunization with BNT162b2 to estimate vaccine effectiveness (VE) in children and adolescents during Omicron variant dominance.

In the Increasing Community Access to the Testing platform, a test-negative, case-control study was performed utilizing data from 6,897 pharmacy-based, drive-through SARS-CoV-2 testing facilities across the US from a single drugstore chain. The study comprised 74,208 samples from children aged 5 to 11 and 47,744 tests from teenagers aged 12 to 15 with COVID-19–like disease who completed SARS-CoV-2 nucleic acid amplification testing between December 26, 2021, and February 21, 2022.

A total of 30,999 test-positive cases and 43,209 test-negative controls from children aged 5 to 11 years old were included, as well as 22,273 test-positive cases and 25,471 test-negative controls from teenagers aged 12 to 15. The median age of individuals who had included tests was 10 years (IQR, 7-13); 61,189 (50.2%) were female, 75,758 (70.1%) were White, and 29,034 (25.7%) were Hispanic/Latino. At 2 to 4 weeks following dose 2, the adjusted OR for children was 0.40 (95% CI, 0.35-0.45; estimated VE, 60.1% [95% CI, 54.7% -64.8%]) and 0.40 for adolescents (95% CI, 0.29-0.56; estimated VE, 59.5% [95% CI, 44.3% -70.6%]).

During month 2 following dose 2, the OR for children was 0.71 (95% CI, 0.67-0.76; estimated VE, 28.9% [95% CI, 24.5% -33.1%]) and 0.83 for adolescents (95% CI, 0.76-0.92; estimated VE, 16.6% [95% CI, 8.1% -24.3%]). The booster dosage OR 2 to 6.5 weeks after the first was 0.29 in teenagers (95% CI, 0.24-0.35; estimated VE, 71.1% [95% CI, 65.5% -75.7%]).

The estimated VE for two doses of BNT162b2 against symptomatic infection in children and adolescents was small and rapidly reduced. After a booster dosage, the estimated efficacy rose in teens.

Reference: jamanetwork.com/journals/jama/fullarticle/2792524