Adverse events following immunization with human papillomavirus vaccine: post-marketing surveillance in China, 2021-2024.

BACKGROUND

Human papillomavirus (HPV) vaccine has been authorized by the National Medical Products Administration for marketing in China since 2016. This study analyzed the adverse events following immunization (AEFI) with all HPV vaccines available in China during 2021-2024: three imported and two domestic HPV vaccines, which were all non-program vaccines approved for females only during the study period.

METHODS

We obtained all AEFI reports and numbers of HPV vaccine doses administered during 2021-2024 from the Chinese National Immunization Information System (CNIIS). We used descriptive epidemiological methods to analyze characteristics and reporting incidence (RI) of HPV vaccine AEFI reports.

RESULTS

During the study period, 163.57 million doses of HPV vaccine were administered and 23,890 HPV vaccine AEFI were reported, for an overall RI of 14.61 AEFI reports per 100,000 doses. Respective AEFI RIs for 9-12-years-old, 13-17-years-olds, 18-30-years-olds, and 31-46-years-olds were 15.01, 16.37, 14.00, and 14.77 per 100,000 doses administered. For bivalent, quadrivalent and 9-valent HPV vaccines, respective RIs were 8.49, 12.65, and 20.50 per 100,000 doses. Most AEFI reports were for common vaccine reactions - injection site reactions (redness/swelling, 6.31 reports per 100,000 doses) and systematic reactions (fever, 3.71 reports per 100,000 doses). The reporting incidence of rare vaccine reactions was 0.49 per 100,000 doses administered, with allergic rash most frequently reported. RIs of serious AEFI and serious rare vaccine reactions were 0.13 and 0.05 per 100,000 doses administered, respectively.

CONCLUSIONS

The immunization safety profile of HPV vaccines available in China during 2021-2024 was acceptable based on this national AEFI data analysis. Serious adverse vaccine reactions were extremely rare; no new or clinically meaningful safety concerns were found.