Safety Monitoring of Bivalent COVID-19 mRNA Vaccines Among Recipients 6 Months and Older in the United States.

PURPOSE: Active monitoring of health outcomes after COVID-19 vaccination provides early detection of rare outcomes post-licensure. We evaluated health outcomes following bivalent COVID-19 Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273.222) vaccination in the United States.

METHODS

Multiple health outcomes were monitored monthly from August 2022 to July 2023 in four administrative claims databases (CVS Health, Carelon Research, Optum, and Medicare). The study included individuals 6 months and older who received a bivalent COVID-19 BNT162b2 or mRNA-1273.222 vaccination during the study period and met a minimum continuous enrollment requirement in a medical insurance plan prior to COVID-19 vaccination. Descriptive analyses monitored counts of vaccinations, outcomes, and concomitant COVID-19 and influenza vaccination. Maximized Sequential Probability Ratio Testing (MaxSPRT) tested for elevations in the observed incidence rate of outcomes post-vaccination compared to annual historical rates estimated from 2019 or 2020, adjusted for claims delay in the observed rate. Where case counts permitted, historical rates were standardized by age and/or sex for all persons, and race and/or nursing home residency status for Medicare persons only.

RESULTS

Overall, 13.9 million individuals 6 months and older received a bivalent COVID-19 vaccine. A statistical signal occurred for two outcomes in one database (significance level of 1%): anaphylaxis following both bivalent COVID-19 vaccines in persons 18-64 years and myocarditis/pericarditis following bivalent BNT162b2 vaccines in individuals 18-35 years. Among 642 142 vaccinated children 6 months-17 years, no signals were identified.

CONCLUSIONS

Results were consistent with published COVID-19 vaccine safety studies and support the safety profile of bivalent COVID-19 mRNA vaccines.