Post-marketing safety profile of palivizumab: a 20-year pharmacovigilance study using the FDA Adverse Event Reporting System (FAERS).

Palivizumab is an FDA-approved monoclonal antibody for preventing severe respiratory syncytial virus (RSV) infections in high-risk children. However, its real-world safety profile, particularly beyond clinical trial populations, remains incompletely characterized. This study aimed to systematically analyze adverse events (AEs) associated with palivizumab using two decades of data from the FDA Adverse Event Reporting System (FAERS) to identify known, novel, and rare safety signals. This study aimed to characterize the post-marketing safety profile of palivizumab and identify AE signals using 20 years of FDA Adverse Event Reporting System (FAERS) data. A retrospective pharmacovigilance study was conducted using FAERS data from Q1 2004 to Q2 2024. Duplicate reports were removed, and palivizumab-related AE reports (primary suspected drug) were extracted. AEs were standardized via MedDRA v27.0 and categorized by system organ classes (SOCs) and preferred terms (PTs). Disproportionality analyses, including reporting odds ratio (ROR), proportional reporting ratio (PRR), multi-item gamma Poisson shrinker (MGPS), and Bayesian Confidence Propagation Neural Network (BCPNN), were used to detect signals, with predefined criteria for signal validation. Among 21,558,936 total FAERS reports, 14,120 (0.065%) palivizumab-related AE cases were included, predominantly in infants aged 28 days-23 months (45.92% of all cases); 51.74% of cases with known sex were male. The most frequent serious outcome was hospitalization (60.98%), followed by death (12.12%). Three system organ class-level positive signals were identified, including two novel signals (Infections and infestations; Congenital, familial and genetic disorders). The strongest preferred term-level positive signals were RSV-related events, with novel signals including infantile spitting up, post-tussive vomiting, oligodipsia, and Kawasaki's disease. This 20-year real-world study confirms known AEs of palivizumab and identifies novel signals, particularly in infection-related and congenital disorder categories. These findings do not establish causality but highlight the need for prospective studies to validate associations, guiding safer clinical use in high-risk pediatric populations.