HPV Infection Common Among American Females

Human papillomavirus is estimated to be the most common sexually transmitted infection in the United States. However, there have been no data on the prevalence of HPV among women across a broad age range and representative of the U.S. population. High-risk HPV types can cause cervical, anal, and other genital cancers. High-risk HPV types are detected in 99 percent of cervical cancers, and worldwide approximately 70 percent of cervical cancers are due to HPV types 16 and 18, according to background information in the article. A highly effective vaccine against HPV types 6, 11, 16, and 18 was licensed in June 2006 and recommended for routine use in females age 11 to 12 years in the United States. Data on type-specific prevalence of HPV in the United States could help measure the effectiveness of the vaccine for reducing infection and could help evaluate its impact and cost effectiveness.

Eileen F. Dunne, M.D., M.P.H., of the Centers for Disease Control and Prevention (CDC), Atlanta, and colleagues estimated the prevaccine prevalence of HPV in the U.S. by performing HPV DNA testing on 2,026 self-collected vaginal swabs among females age 14 to 59 years participating in the National Health and Nutrition Examination Survey (NHANES) 2003-2004.

Of the 1,921 adequate specimens, 26.8 percent were positive for any HPV DNA. Using January 2004 population estimates and extrapolating this prevalence rate to the population, the authors estimate that approximately 24.9 million females in this age range have prevalent HPV infection. Prevalence of any HPV infection was highest among females age 20 to 24 years (44.8 percent); overall HPV prevalence among females age 14 to 24 years was 33.8 percent. This prevalence corresponds with 7.5 million females with HPV infection, which is higher than the previous estimate of 4.6 million HPV infections among females in this same age group in the United States.

There was a significant trend for increasing HPV prevalence with each year of age from 14 to 24 years, followed by a gradual decline in HPV prevalence through 59 years. Independent risk factors for HPV detection were age, marital status and increasing numbers of lifetime and recent sex partners.

Overall, HPV types 6, 11, 16, or 18 were detected in 3.4 percent of the study participants, corresponding with 3.1 million females with prevalent infection with HPV types included in the quadrivalent HPV vaccine.

"Our study provides the first national estimate of prevalent HPV infection among females aged 14 to 59 years in the United States," the authors write. "Our data indicate that the burden of prevalent HPV infection among women was higher than previous estimates."