Post-marketing safety monitoring of RSV vaccines: A real-world study based on the Vaccine Adverse Event Reporting System (VAERS)

Two protein subunit vaccines - RSVPreF3 (Arexvy, GSK) and RSVpreF (Abrysvo, Pfizer) - and one mRNA RSV vaccine, mRNA-1345 (mRESVIA, Moderna), have been approved. Post-marketing surveillance is crucial for evaluating the safety of RSV vaccines. We reviewed VAERS reports on RSV vaccines, using the Reporting Odds Ratio (ROR) and Bayesian Confidence Propagation Neural Network (BCPNN) to identify safety signals. Our analysis incorporated severity, time-to-onset, subgroup, and sensitivity analyses to enhance key findings. After analyzing 5,147 RSVPreF3, 2,734 RSVpreF, and 35 mRNA-1345 reports, 91, 103, and 8 positive PT signals were found, respectively. Among serious reports, both RSVPreF3 and RSVpreF were associated with 9 important medical events (IMEs), including immune thrombocytopenia, which was also classified as a designated medical event (DME). Three pregnancy-related IME signals-hemorrhage in pregnancy, fetal death, and fetal hypokinesia - were reported for RSVpreF. Descriptive analysis of time-to-onset complemented the overall safety profiling, and sensitivity analysis offered further support for the observed disproportional reporting trends in certain adverse events (AEs). Our study utilized real-world data from large-scale spontaneous reporting systems to detect AEs that were disproportionately reported following RSV vaccination, thereby generating early safety signals to inform hypothesis development and support clinical awareness.