Vaccine Effectiveness, School Reopening, and Risk of Omicron Infection Among Adolescents Aged 12-17 Years.

PURPOSE

The BNT162b2 (Pfizer-BioNTech) is approved for adolescents aged 12-17 years. We estimated BNT162b2 vaccine effectiveness (VE) and a booster dose effectiveness in adolescents aged 12-17 years and the impact of opening schools and the Omicron variant on risk of SARS-CoV-2 infection in adolescents.

METHODS

We used logistic regression with a test-negative design controlling for gender and race to estimate BNT162b2 VE and the effectiveness of a booster dose in adolescents aged 12-17 years. To evaluate the effect of school opening on Omicron transmission, we used Cox proportional hazards regression to compare adolescents to a reference group of adults aged 22-33 or aged 65+ years, investigating whether risk for adolescents increased relative to the reference group after school opened.

RESULTS

We found that adolescents who received two BNT162b2 doses had significant protection against Omicron infection in the first three months following their second dose (VE = 54.5%, confidence interval [CI]: [17.8%-76.9%], p = .014) but no protection afterwards. Receiving a booster dose was associated with lower risk of infection (odds ratio = 0.48, CI: [0.33-0.69], p < .0001) and restored efficacy to a similar level (VE = 56.3%, CI: [36.5%-70.6%], p < .0001). We observed a statistically significant increase (p = .04) in adolescent infection risk relative to adults in the period of Omicron predominance.

DISCUSSION

The BNT162b2 vaccine is effective at preventing SARS-CoV-2 infection in adolescents but immunity against Omicron wanes rapidly and booster doses are needed to retain protection. More research is needed to determine the effect of school reopening on spread in the Omicron-dominant period.