Does Quadrivalent HPV Vaccine Protect Against Nonvaccine Serotypes?

The quadrivalent human papillomavirus (HPV) vaccine provides excellent protection against four HPV types (6, 11, 16, and 18). Types 16 and 18 cause about 70% of cervical cancers worldwide. Two related studies evaluated the efficacy of the quadrivalent vaccine against nonvaccine oncogenic HPV types in 17,622 women (age range, 16–26 years) enrolled in international industry-sponsored, placebo-controlled, randomized trials. Participants underwent cervicovaginal sampling and Pap testing at baseline and every 6 to 12 months. HPV genotyping was performed on biopsy samples. The nonvaccine HPV types examined by the researchers share at least 60% amino acid homology with vaccine strains and account for about 20% of cervical cancers.

The first study e…