virus-like-particle vaccine on risk of cervical intraepithelial neoplasia grade 2, grade 3, and adenocarcinoma in situ: a combined analysis of four randomised clinical trials

Methods 20 583 women aged 16–26 years were randomised to receive quadrivalent HPV6/11/16/18 vaccine (n=9087), its HPV16 vaccine component (n=1204), or placebo (n=10 292). They underwent periodic Papanicolaou testing, with colposcopy or biopsy for detected abnormalities. The primary composite endpoint was the combined incidence of HPV16/18-related CIN2/3, AIS, or cervical cancer. These trials are registered at ClinicalTrials.gov, numbers NCT00365378, NCT00365716, NCT00092521, and NCT00092534.