Surveillance analysis of adverse events following immunization with the bivalent human papillomavirus vaccine and recombinant human papillomavirus 9-valent vaccine in Hebei province from 2018 to 2022

ObjectiveTo analyze the characteristics of adverse events following immunization (AEFI) after the administration of the bivalent human papillomavirus vaccine (HPV2) and the recombinant human papillomavirus 9-valent vaccine (HPV9) in Hebei province, and to evaluate the post-marketing safety of HPV2 and HPV9. MethodsData on AEFI cases following HPV2 and HPV9 vaccination from October 1, 2018, to December 31, 2022, were collected from the AEFI monitoring module of the China Information System for Disease Control and Prevention. The incidence of AEFI reports for HPV2 and HPV9 were compared and analyzed. ResultsFrom October 1, 2018, to December 31, 2022, the average annual incidence of total AEFI reports following HPV2 and HPV9 vaccination in Hebei province was 2.76 per 100 000 doses, with HPV2 and HPV9 at 3.38 per 100 000 doses and 2.39 per 100 000 doses respectively (χ2 = 2.422, P > 0.05). The AEFI mainly comprised adverse reactions, with a total incidence of 2.69 per 100 000 doses, including common reactions and abnormal reactions at 2.42 per 100 000 doses and 0.28 per 100 000 doses respectively. For HPV2, the rates of common reactions and abnormal reactions were 2.22 per 100 000 doses and 0.11 per 100 000 doses respectively, while for HPV9 they were 2.74 per 100 000 doses and 0.55 per 100 000 doses respectively. The differences in the rates of common reactions and abnormal reactions between the two vaccines were not statistically significant (χ2 = 0.757, 3.256, P > 0.05 for both). The most common reaction was local redness and swelling (1.28 per 100 000 doses), and the primary abnormal reaction was anaphylactic shock (0.07 per 100 000 doses), mostly occurring within 24 hours post-vaccination. Ninety percent of individuals with AEFI recovered or showed improvement.ConclusionsAs of the end of 2022, the overall safety of HPV2 and HPV9 vaccinations in Hebei province was favorable, with a very low incidence rate of abnormal reactions.