Adverse events after Pfizer's Respiratory Syncytial Virus Vaccine in pregnant women in the Vaccine Adverse Event Reporting System, 2024-2025, United States.

BACKGROUND

In September 2023, the Advisory Committee on Immunization Practices recommended Pfizer's Respiratory Syncytial Virus (RSV) vaccine (Abrysvo ®) for pregnant women at 32-36 weeks' gestation using seasonal administration to prevent RSV-associated lower respiratory tract disease (LRTD) in infants aged <6 months.

METHODS

We searched and analyzed reports of adverse events (AEs) after administration of Pfizer's RSV Vaccine in pregnant women submitted to the U.S. Vaccine Adverse Event Reporting System (VAERS) for the 2024-2025 RSV season. Clinicians reviewed reports and available medical records.

RESULTS

VAERS received 131 reports of pregnant women who received the Pfizer RSV vaccines. Injection site and systemic reactions were described in 46 (35%) reports. The most reported pregnancy-specific outcomes were preterm birth (n = 15, 11%) and hypertensive disorders of pregnancy (HDP) (n = 9, 7%).

CONCLUSIONS

During the second U.S. RSV season in which the Pfizer RSV vaccine was recommended for use during pregnancy, the types of AEs reported were consistent with prelicensure studies.