Human papillomavirus infections and vulvar disease development.

BACKGROUND We describe the prevalence of 14 common types [human papillomavirus (HPV)-6/11/16/18/31/33/35/39/45/51/52/56/58/59] in vulvar intraepithelial neoplasia grades 1 to 3 (VIN 1-3) and HPV genotype-specific infection in relation to the development of VIN 1-3. METHODS Data were analyzed from women enrolled in the placebo arms of three randomized double-blind trials. Anogenital examinations, including collection of labial/vulvar/perineal/perianal swabs, occurred at day 1 and every 6 to 12 months through 48 months. Lesions that were possibly, probably, or definitely HPV related or of unknown etiology were biopsied. Biopsies and swabs were HPV typed. Biopsies were read for endpoint determination (VIN 1-3) by up to four pathologists. RESULTS Incident infection with HPV-16 was the most common (6.0/100 person-years). The mean time from incident infection to the development of VIN 1-3 was 18.5 months (95% confidence interval, 13.4-23.6). HPV-6 or -11 was observed in 64.5% of VIN 1 and 29.0% of VIN 2/3, whereas HPV-16 was observed in 6.5% of VIN 1 and 64.5% of VIN 2/3. CONCLUSION A vaccine that includes both low- and high-risk types could prevent more than half of VIN 1-3 lesions, including the precursor lesions to HPV-related vulvar carcinoma. Understanding the incidence and duration of vulvar HPV infection and risk for progression to VIN 1-3 may inform therapeutic decisions for vulvar disease and mathematical models that assess the cost-effectiveness of vaccination.