[Evaluation of the 10-year protective effect and immunogenicity of quadrivalent HPV vaccination].

To evaluate the 10-year protective effect and immunogenicity of quadrivalent human papillomavirus (HPV) vaccine in Chinese women aged 20 to 45 years. From October 2019 to April 2020, a long-term follow-up study was conducted on the subjects of the Phase III clinical trial of the quadrivalent HPV vaccine (NCT00834106). Participants underwent a questionnaire survey, venous blood sampling, gynecological examination, cervical exfoliated cell pathology examination, and serum neutralizing antibody titers for HPV-6, 11, 16, and 18 were measured using a pseudovirus neutralization assay. The results of the cytological examination and the positive rate and titers of serum antibodies of different cervical exfoliated cells were compared. A total of 889 subjects were followed up, including 240 in the control group, 453 in the vaccination group and 196 in the post-trial vaccination group. The age of the control group was (40±7) years old, which was higher than that of the supplementary vaccination group and the vaccination group [(38±4) and (38±6) years old, respectively] (<0.05). There were no statistically significant differences in condom use and sexual frequency among all groups (all values>0.05). The abnormal proportion of cervical exfoliation cytopathology in the vaccination group was 3.7% (17/453), which was significantly lower than that in the control group [9.6% (23/240)] and post-trial vaccination group [5.6% (11/196)] (<0.05). There were two cases of cervical intraepithelial neoplasia (CIN) grade 1 in the vaccination group, two cases of CIN grade 1 and three cases of CIN grade 2 and above in the control group, and no CIN grade 1 and above cases in the post-trial vaccination group. The positive rate of HPV-18 antibody was 35.5% (161/453) in the vaccination group and 76.0% (149/196) in the post-trial vaccination group, which was significantly lower than that of other types (<0.05). The neutralizing antibody GMT ratio between the vaccination group and the control group ranged from 2.62 to 25.33 (9.05 to 83.08). Protective neutralizing antibodies are sustained in Chinese women aged 20 to 45 years after ten years of vaccination with quadrivalent HPV vaccine.