Safety Profile of the Bivalent RSVpreF Vaccine (Abrysvo®) Administered During Pregnancy: An Active Real-World Pharmacovigilance Study in Panama, 2025

Background/Objectives. Respiratory syncytial virus (RSV) is an important cause of acute lower respiratory infection in infants. Panama introduced the bivalent prefusion F vaccine (RSVpreF) for administration between 32.0 and 36.6 weeks of gestation in July 2025. In this tropical setting, respiratory viruses are detected throughout the year, with RSV activity increasing during the rainy season. We characterized self-reported maternal and neonatal events and outcomes to generate early post-introduction real-world safety evidence from Central America. Methods. This retrospective descriptive observational study included women aged 18 years or older vaccinated with RSVpreF between 32.0 and 36.6 weeks of gestation from July through December 2025 and recruited from January through July 2026. Structured telephone, virtual, or in-person interviews were used. We calculated absolute and relative frequencies and 95% Wilson confidence intervals (CIs). Results. Of 225 questionnaires obtained, 200 were eligible for analysis. Mean maternal age was 28.1 years (SD 6.4). At least one reaction was reported by 55.5% of participants, mainly local; injection-site pain was most frequent (48.0%). At least one obstetric condition was reported by 17.5%, including hypertensive disorders of pregnancy (12.0%). Preterm birth occurred in 2.0% and low birth weight in 2.5%. No fetal or neonatal deaths, thrombocytopenia, paralysis, facial paralysis, or Guillain–Barré syndrome were reported. Jaundice was the most frequent neonatal morbidity (20.0%). Conclusions. In this cohort, self-reported reactogenicity was mainly local, and no unexpected cluster of events was apparent. Participant selection, retrospective self-report, absence of an unvaccinated comparator, and sample size limit risk estimation and detection of uncommon events. The findings provide early active-pharmacovigilance evidence from Central America and support continued surveillance with clinically verified maternal and neonatal outcomes.