The 13-year long-term follow-up on the effectiveness and immunogenicity of the quadrivalent human papillomavirus vaccine in Chinese females vaccinated at 20–45 years of age

The quadrivalent human papillomavirus (qHPV) vaccine demonstrated high efficacy against vaccine-type-related precancers in Chinese females through a 6.6-year double-blind, randomized control trial (V501–041, NCT00834106). We present results for its long-term follow-up (LTFU) phase, evaluating vaccine effectiveness and immunogenicity throughout 13 years post Dose 1. Participants receiving qHPV vaccines at ages 20–45 in the V501–041 study constituted the early vaccination group (EVG). Those who received the placebo in V501–041 but were vaccinated during 2018–2020 formed the catch-up vaccination group (CVG), while the control group (CG) comprised those remaining unvaccinated throughout V501–041 and LTFU. The primary endpoint was histopathologically-confirmed cervical intraepithelial neoplasia (CIN) 2+ tested PCR-positive for HPV-16/18. Antibodies against HPV-6, 11, 16, and 18 were assessed using an immunoglobulin G (IgG) Luminex immunoassay at year 13. A total of 1100 participants from V501–041, of whom 978 were followed in LTFU, were included with a median follow-up of 152.2 months. No cases of the primary endpoint were observed in the EVG during 5513.6 person-years of follow-up, while one case was observed in the CG over 2951.4 person-years of follow-up, indicating a 100% risk reduction in the EVG compared to the CG. In the CVG, no cases were detected from vaccination to the latest follow-up (0.0 per 10 000 person-years), contrasting with an incidence of 22.3 per 10 000 person-years prior to vaccination. Seropositivity rates at year 13 remained >92% (for HPV-6/11/16) and 84% (HPV-18). These findings demonstrated continued vaccine protection against cervical precancers and sustained immunogenicity through 13 years post-vaccination.Trial Registration The LTFU study was registered at the Chinese Clinical Trial Registry, ChiCTR2100052313.