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

Importance: COVID-19 vaccines are authorized for use in children in the United States; real-world assessment of vaccine effectiveness in children is needed. Objective: To estimate the effectiveness of receiving a complete primary series of monovalent BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine in US children. Design: A cohort study of children aged 5--17 years vaccinated with BNT162b2 matched with unvaccinated children. Setting: Participants 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). Participants: Vaccinated 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. Exposure: BNT162b2 vaccinations were identified using IIS vaccination records and insurance claims. Main Outcomes and Measures: Two 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. Results: There 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 Relevance: Receipt 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.

Characterization of Long COVID among U.S. Medicare Beneficiaries using Claims Data (preprint)

This retrospective study utilized healthcare claims data to investigate the incidence, patient demographics, and concurrent diagnoses associated with long COVID in the U.S. Medicare population. Nearly 194,000 (0.6%) beneficiaries had post-COVID condition diagnoses, with higher rates among nursing home residents. Of those medically attended for COVID-19, 3-5% were diagnosed with post-COVID conditions. We observed minimal demographic differences between those with and without long COVID. When comparing diagnoses concurrent with long COVID and COVID-19, certain codes (G72 and J84) for myopathies and interstitial pulmonary diseases were disproportionately present with long COVID.