Efficacy of a bivalent L1 virus-like particle vaccine in prevention of infection with human papillomavirus types 16 and 18 in young women: a randomised controlled trial

Vaccination against the most common oncogenic human papillomavirus (HPV) types, HPV-16 and HPV-18, could prevent development of up to 70% of cervical cancers worldwide. We did a randomised, double-blind, controlled trial to assess the efficacy, safety, and immunogenicity of a bivalent HPV-16/18 L1 virus-like particle vaccine for the prevention of incident and persistent infection with these two virus types, associated cervical cytological abnormalities, and precancerous lesions. We randomised 1113 women between 15–25 years of age to receive three doses of either the vaccine formulated with AS04 adjuvant or placebo on a 0 month, 1 month, and 6 month schedule in North America and Brazil. Women were assessed for HPV infection by cervical cytology and self-obtained cervicovaginal samples for up to 27 months, and for vaccine safety and immunogenicity. In the according-to-protocol analyses, vaccine efficacy was 91·6% (95% CI 64·5–98·0) against incident infection and 100% against persistent infection (47·0–100) with HPV-16/18. In the intention-to-treat analyses, vaccine efficacy was 95·1% (63·5–99·3) against persistent cervical infection with HPV-16/18 and 92·9% (70·0–98·3) against cytological abnormalities associated with HPV-16/18 infection. The vaccine was generally safe, well tolerated, and highly immunogenic. The bivalent HPV vaccine was efficacious in prevention of incident and persistent cervical infections with HPV-16 and HPV-18, and associated cytological abnormalities and lesions. Vaccination against such infections could substantially reduce incidence of cervical cancer.