Adverse events following HPV vaccine reported to the Vaccine Adverse Event Reporting System

Abstract

Background Vaccination against high-risk HPV types is a key preventive measure. However, concerns regarding vaccine safety may hinder vaccination efforts. This study aims to evaluate adverse events (AEs) reported in the Vaccine Adverse Event Reporting System (VAERS) following HPV vaccination from 2006 to 2024, providing insights into its safety profile. Methods We analyzed VAERS data, a spontaneous reporting system containing de-identified AE reports. Four disproportionality analyses (ROR, PRR, BCPNN, and MGPS) were applied, and adverse event signals were defined only when the positive criteria were simultaneously met across all four methods. Statistical analyses were performed using R software and Microsoft Excel, with a significance threshold of p < 0.05. Results A total of 77,909 HPV vaccine-related AE reports were analyzed, with 68.4% involving females and 48.7% affecting individuals under 18. Serious AEs accounted for 11,659 reports, with headache and fatigue being the most common. Syncope was the most frequent signal, while postural orthostatic tachycardia syndrome (POTS) exhibited the strongest signal strength. Approximately 90% of AEs occurred within 30 days post-vaccination. Among vaccine types, HPV4 had the highest number of reports, and intramuscular injection was the most common administration route. Conclusion This study offers an updated pharmacovigilance assessment of adverse events reported following HPV vaccination, highlighting reported patterns and statistical signals that may warrant further investigation.