Yangjiang

Researchers are evaluating the immune persistence of the quadrivalent HPV vaccine in healthy Chinese females aged 9 to 45 years. The study focuses on women who have previously received the complete three-dose vaccination schedule at months 0, 2, and 6. The goal is to assess how well immunity against the HPV types contained in the vaccine lasts over time. Participants in this phase 3, open-label, non-randomized trial have completed the full HPV vaccination schedule and provided blood samples at month 7 in earlier related studies. This study follows them to monitor immune response persistence through various time points up to 60 months after vaccination. During the study, participants will be monitored at months 12, 24, 36, 48, and 60 to measure seroconversion rates and geometric mean titers for each HPV type in the vaccine. These immune markers will help determine how long protection lasts. Participants must agree to regular follow-ups and provide blood samples during these visits to evaluate the vaccine's long-term immune response.