Epidemiology of genital human papillomavirus infection.

Although it is difficult to estimate the overall prevalence of genital human papillomavirus (HPV) infection, current figures suggest that visible genital warts are present in approximately 1% of sexually active adults in the United States and that at least 15% have subclinical infection, as detected by HPV DNA assays. Genital HPV infection is thus extremely common. The highest rates of genital HPV infection are found in adults 18-28 years of age. Although risk factors for infection are difficult to assess because of the high frequency of subclinical infection, it is clear that major risk factors for acquiring genital HPV infection involve sexual behavior, particularly multiple sex partners. Other possible risk factors for acquisition of genital HPV infection include oral contraceptive use, pregnancy, and impairment of cell-mediated immunity. Strong epidemiologic and molecular data link HPV infection to cervical and other anogenital cancers. The types of HPV most commonly detected in cancers are HPV-16 and HPV-18. In summary, genital HPV infection is common among sexually active populations and causes both benign and malignant neoplasms of the genital tract.