Post-Marketing Safety Surveillance of HPV Vaccines in Anhui Province, China, 2017-2024

Background: The Human Papillomavirus (HPV) vaccine has been globally implemented to prevent HPV-associated diseases. Since its introduction in China in 2017, this vaccine has substantially reduced the burden of HPV-related health conditions. As more people get vaccinated these days, ongoing safety monitoring and evaluation have become critical. This helps to safeguard public trust in immunization programs and ensures the sustainability of immunization programs. Methods: Suspected adverse events following immunization (AEFIs) associated with HPV vaccination from 2017 to 2024 were extracted from the Chinese National Immunization Information System (CNIIS). Data on the number of HPV vaccine doses given came from the Immunization Planning Information Management System of Anhui Province. Descriptive statistical methods examined the distribution characteristics of AEFIs, and chi-square tests assessed differences in incidence rates. Results: From 2017 to 2024, the vaccine safety surveillance system in Anhui Province monitored a total of 1149 reports of AEFIs associated with the HPV vaccine. The reported overall rate of AEFIs was 16.32 per 100,000 doses. Specifically, the rates of common adverse reactions were 15.15 per 100,000 doses, while the rates for rare adverse reactions were 0.85 per 100,000. Among the common adverse reactions, the incidence rates of injection-site redness and swelling (diameter >5.0 cm), induration (diameter >5.0 cm), and fever (axillary temperature ≥38.6 °C) were 0.60, 0.33, and 1.34 per 100,000 doses, respectively. For rare adverse reactions, the reported incidence rates of allergic rash, allergic urticaria, and aseptic abscess were 0.50, 0.09, and 0.03 per 100,000 doses, respectively. Most AEFIs occurred within 24 h post-vaccination. Conclusions: The overall reported incidence of AEFIs following HPV vaccination in Anhui Province from 2017 to 2024 was low, with serious rare adverse reaction occurring infrequently. These findings suggest that the HPV vaccine has a favorable safety profile.