Objective: To report the sequential surveillance findings for 10 prespecified safety outcomes of exposure to RSVpreF during pregnancy over the course of its first vaccination season in the US.
Design, Setting, and Participants: This cohort study with a sequential surveillance design used health plan data from 5 research partners. Health insurance data were analyzed across 5 sequential surveillance periods from April 25, 2024, through April 10, 2025. Pregnancies of individuals aged 15 to 54 years that culminated in a live birth or stillbirth and reached 32 gestational weeks were included. Cohorts included pregnancies exposed to RSVpreF (between September 22, 2023, and August 9, 2024); comparator pregnancies receiving influenza, COVID-19, and/or Tdap (tetanus, diphtheria, and acellular pertussis) vaccines but not the RSVpreF concurrently; and historical comparator pregnancies (vaccinated between September 1, 2018, and January 31, 2023).
Exposure: RSVpreF or comparator vaccines (influenza, COVID-19, and/or Tdap but not RSVpreF) between 32 through 36 weeks’ gestation.
Main Outcomes and Measures: Primary outcomes were preterm birth and pregnancy-associated hypertensive disorders (composite of gestational hypertension; preeclampsia; eclampsia; hemolysis, elevated liver enzymes, and low platelet syndrome; or preexisting hypertension superimposed with preeclampsia or eclampsia). Secondary outcomes included premature rupture of membranes (PROM), preterm labor without preterm delivery, preterm PROM, maternal Guillan-Barré syndrome, and stillbirth. Infant outcomes were large for gestational age, small for gestational age, and low birth weight. Crude incidence proportions (IPs) and adjusted relative risks (ARR) were identified for these outcomes.
Access on PubMed
Michnick AI, MacDonald SC, Adimadhyam S, Zhang F, Cosgrove A, Petrone AB, Round KE, Gandhi S, Koram N, Anastasiou OE, Rubino H, Lino MM, Djibo DA, Kuntz JL, Love SM, McMahill-Walraven CN, Palmsten K, Wentz AE, Andrade SE, Platt R, Maro JC. Sequential Safety Surveillance of RSVpreF Vaccination During Pregnancy Early in the Postapproval Period. JAMA Netw Open. 2026 Apr 1;9(4):e266190. doi: 10.1001/jamanetworkopen.2026.6190. Erratum in: JAMA Netw Open. 2026 May 1;9(5):e2617937. doi: 10.1001/jamanetworkopen.2026.17937. PMID: 42012833; PMCID: PMC13100873.
