Adverse event following immunization with domestic bivalent human papillomavirus vaccine in Hebei Province, China...

This study investigated the incidence and characteristics of adverse events following immunization (AEFI) with the domestic bivalent human papilloma virus (HPV) vaccine among females aged 9-45 years in Hebei Province between 2022 and 2024. All vaccination and AEFI data were obtained from the Immunization Information Management System (IIMS) and the National Adverse Event Following Immunization Surveillance System (NAEFISS) in Hebei Province. Descriptive and analytical epidemiological methods were used for statistical analysis. The domestic bivalent HPV vaccine had an AEFI reporting rate of 4.54 per 100,000 doses, comprising common vaccine reactions (3.97/100,000), rare vaccine reactions (0.42/100,000). Significant differences in common vaccine reactions were observed across age groups 9-14 years versus both 15-26 years (χ² = 6.222, p = .016) and 27-45 years (χ² = 26.082, p < .001), whereas rare vaccine reactions showed no significant age-based differences (all p > .05). The AEFI reporting rates in 2022, 2023, and 2024 were 2.47, 4.70, and 9.93 per 100,000 doses, respectively, showing a significant linear increasing trend (r = 0.004, p < .05). The highest AEFI reporting rate occurred between April and June (5.50 per 100,000 doses). Statistically significant differences were observed between the 1st dose versus both the 2nd (χ² = 6.618, p = .012) and 3rd doses (χ² = 11.205, p = .001), but not between the 2nd and 3rd doses (χ² = 1.466, p = .275). Among clinical symptoms, common vaccine reactions primarily included fever and injection-site swelling/induration, while allergic rash was the most frequent rare vaccine reaction. The 9-14-year-old age group exhibited a higher risk of AEFI compared to both the 15-26-year-old and 27-45-year-old groups, with the majority of events being common vaccine reactions.