Maternal Bivalent Respiratory Syncytial Virus Prefusion F (RSVpreF) Vaccination in Panama: A Retrospective Follow-Up Study.

BACKGROUND

Panama introduced routine maternal bivalent respiratory syncytial virus prefusion F (RSVpreF) vaccination (Abrysvo, Pfizer Inc., New York, NY) in July 2025. We described common retrospectively self-reported reactions and maternal, perinatal, and neonatal conditions among the first 200 eligible recipients enrolled in active follow-up.

METHODS

This retrospective descriptive cohort included women aged 18 years or older who received RSVpreF at 32.0-36.6 weeks of gestation from July through December 2025 and completed one structured interview, generally after delivery, from January through July 2026. Exact vaccination-to-interview intervals were unavailable. Frequencies and Wilson 95% confidence intervals were calculated.

RESULTS

Of 225 completed questionnaires, 200 met the eligibility criteria. The mean maternal age was 28.1 years (standard deviation = 6.4). Any reaction was reported by 55.5% (95% CI: 48.6%-62.2%), most often injection-site pain (48.0%), and self-reported fever occurred in 2.5%. A participant-reported hypertensive disorder occurred in 12.0%. Four births were preterm (2.0%), and five newborns had low birth weight (2.5%). Participant-reported jaundice was the most frequent neonatal condition (20.0%).

CONCLUSIONS

Reported reactions were mainly local and short-lived. These findings describe early implementation in Panama but do not assess vaccine effectiveness, comparative safety, rare-event risk, or causality. Convenience recruitment, post-delivery selection, retrospective recall, absence of clinical verification and a comparator, and missing baseline risk and event-timing data limit interpretation.