Do We Need All Three Doses of HPV Vaccine to Protect Against Genital Warts?

The quadrivalent human papillomavirus (HPV) vaccine provides protection against HPV types 6 and 11 (which cause most genital warts) as well as oncogenic HPV types 16 and 18. The recommended immunization schedule calls for vaccine administration at 0, 2, and 6 months; however, many women do not receive all three doses. Using combined data from nationwide registries in Sweden, investigators assessed the effectiveness of one, two, or three doses of HPV vaccine for prevention of genital warts in girls and women (age range, 10–24 years). In a cohort of >1 million women followed for a mean of 3.8 years, more than 300,000 received the vaccine. Women with diagnoses of genital warts prior to vaccination were excluded.

Compared with risk for genital w…