Poster presented at the 41st Annual International Society for Pharmacoepidemiology Conference
Background: The original Pfizer-BioNTech monovalent COVID-19 vaccine (BNT162b2) was authorized for emergency use in December 2020 and received approval in 2021. Myocarditis/pericarditis (myo/peri) has been reported as an adverse event in younger males after dose 2, with onset typically occurring within 7 days after vaccination. We present an interim analysis of post-vaccination myo/peri incidence rates from an ongoing US postapproval safety study of BNT162b2 [EUPAS43468].
Objectives: To describe incidence rates (IR) of myo/peri in BNT162b2 vaccinees and matched unvaccinated individuals.
Methods: BNT162b2 vaccinees aged ≥ 6 months were identified in data from 5 insurers participating in the Sentinel System from December 2020-April 2023. Insurance claims were supplemented with immunization information systems data, when available. Unvaccinated individuals were matched to eligible vaccinees with ≥ 1 year prior health plan enrollment in a variable ratio of up to 2:1 by age, sex, US state, calendar month, and propensity score (PS). The PS included demographics, comorbidities, prior medication use, other vaccines, and healthcare utilization. We identified myo/peri with diagnosis codes and estimated IRs per 100,000 person-years and 95% confidence intervals (CI) by exposure status in the matched population in the 1-21 and 1-7 (secondary definition) days after vaccination, overall and stratified by age, sex, and dose number (1st, 2nd, 3rd).
Results: Prior to matching there were 8 million (M) 1st dose, 6.6M 2nd dose, and 32,931 3rd dose BNT162b2 vaccinees and 25.5M potential comparators. We matched 7.2M 1st dose, 5.8M 2nd dose, and 32,910 3rd dose vaccinees to 13.7M, 11M and 65,806 unvaccinated individuals, respectively. The age distribution was: 6 months–4 yrs=1%, 5–11 yrs=7%, 12–17 yrs=10%, 18–64 yrs=58%, ≥ 65 yrs=24%; overall 53% were female.
In the 1-21 days after at least 1 dose, there were 455 exposed and 695 unvaccinated myo/peri cases identified and the overall IR was numerically higher in the exposed (61.5, CI, 56.1–67.4) than unvaccinated (50.4, CI, 46.8-54.3). IR were numerically higher in exposed than unvaccinated in males [79.1 (CI, 70.1–89.0) vs 58.4 (CI, 52.7–64.6)], and younger individuals [12-17 yrs: 85.5 (CI, 65.2-110.0) vs 19.5 (CI, 12.5-29.0); 18-24 yrs:113.0 (CI 86.7-144.9) vs 50.3 (CI, 37.7-65.9); 30-39 yrs: 47.1 (CI, 34.1-63.5) vs. 24.6 (CI, 17.7-33.2)]. IRs were higher in exposed than unexposed after dose 2 [74.3 (CI, 65.3-84.2) vs 50.0 (CI 44.6-55.9)]. There were no myo/peri events in the dose 3 matched cohorts. The 1-7 day risk period results were consistent with the main analysis.
Conclusions: The observations of higher myo/peri IRs in the exposed after dose 2, among males, and in younger age groups are consistent with other studies.
