Effectiveness of BNT162b2 COVID-19 Vaccination in Children Aged 5-17 Years in the United States

ImportanceCOVID-19 vaccines are authorized for use in children in the United States; real-world assessment of vaccine effectiveness in children is needed. ObjectiveTo estimate the effectiveness of receiving a complete primary series of monovalent BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine in US children. DesignA cohort study of children aged 5-17 years vaccinated with BNT162b2 matched with unvaccinated children. SettingParticipants identified in Optum and CVS Health insurance administrative claims databases were linked with Immunization Information System (IIS) COVID-19 vaccination records from 16 US jurisdictions between December 11, 2020, and May 31, 2022 (end date varied by database and IIS). ParticipantsVaccinated children were followed from their first BNT162b2 dose and matched to unvaccinated children on calendar date, US county of residence, and demographic and clinical factors. Censoring occurred if vaccinated children failed to receive a timely dose 2 or if unvaccinated children received any dose. ExposureBNT162b2 vaccinations were identified using IIS vaccination records and insurance claims. Main Outcomes and MeasuresTwo COVID-19 outcome definitions were evaluated: COVID-19 diagnosis in any medical setting and COVID-19 diagnosis in hospitals/emergency departments (EDs). Propensity score-weighted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with Cox proportional hazards models, and vaccine effectiveness (VE) was estimated as 1 minus HR. VE was estimated overall, within age subgroups, and within variant-specific eras. Sensitivity, negative control, and quantitative bias analyses evaluated various potential biases. ResultsThere were 453,655 eligible vaccinated children one-to-one matched to unvaccinated comparators (mean age 12 years; 50% female). COVID-19 hospitalizations/ED visits were rare in children, regardless of vaccination status (Optum, 41.2 per 10,000 person-years; CVS Health, 44.1 per 10,000 person-years). Overall, vaccination was associated with reduced incidence of any medically diagnosed COVID-19 (meta-analyzed VE = 38% [95% CI, 36%-40%]) and hospital/ED-diagnosed COVID-19 (meta-analyzed VE = 61% [95% CI, 56%-65%]). VE estimates were lowest among children 5-11 years and during the omicron variant era. Conclusions and RelevanceReceipt of a complete BNT162b2 vaccine primary series was associated with overall reduced medically diagnosed COVID-19 and hospital/ED-diagnosed COVID-19 in children; observed VE estimates differed by age group and variant era. KEY POINTSO_ST_ABSQuestionC_ST_ABSDoes receiving a complete primary series of monovalent BNT162b2 COVID-19 vaccine reduce COVID-19 diagnoses and ED visits/hospitalizations in children aged 5-17 years? FindingsIn this cohort study evaluating vaccination records and medical encounters from 827,149 children, recipients of a complete primary series of BNT162b2 generally had lower rates of COVID-19 diagnoses and ED visits/hospitalizations than unvaccinated children. Vaccine effectiveness was lower in children aged 5-11 years and during omicron variant predominance. MeaningReceiving a primary series of monovalent BNT162b2 COVID-19 vaccine is effective in preventing COVID-19 diagnoses; changing variants and younger age groups may require further evaluations.