One quarter of US women infected with HPV

NEW YORK (Reuters Health) - Just over one in four US women aged 14 through 59 are infected with the human papillomavirus (HPV), but the strains of the virus linked to cervical cancer are found in fewer than one in 30 women, researchers from the Centers for Disease Control and Prevention report.

The study is the first to look at HPV prevalence throughout the population and across age groups, and will provide a baseline for gauging the effectiveness of the HPV vaccine that the US Food and Drug Administration approved in 2006, Dr. Dr. Eileen F. Dunne and colleagues write in this week's Journal of the American Medical Association.

Dunne and her team analyzed self-collected vaginal swabs from 1,921 women aged 14 to 59 participating in the 2003-2004 National Health and Nutrition Examination Survey. Overall, 27 percent of the samples tested positive for HPV.

Infection was most common among women aged 20 to 24, 45 percent of whom tested positive for the virus, while 25 percent of girls and women aged 14 to 19 had HPV. The prevalence of infection rose steadily from age 14 up to 24, and then showed a gradual decline until age 59.

The cancer-linked HPV strains -- 6, 11, 16 and 18 -- which are targeted by the new vaccine, were found in 3.4 percent of the study participants.

The CDC currently recommends that girls aged 11 and 12 get the new vaccine, and that females between 13 and 26 get "catch-up" vaccines, Drs. Susan C. Weller and Lawrence R. Stanberry of the University of Texas Medical Branch in Galveston note in an editorial accompanying the study.

Future studies should investigate how common the highest-risk HPV subtypes, 16 and 18, are among women older than 26 to determine if they would also benefit from the vaccine, they write.

Follow-up studies will be essential to determine if other risky HPV strains might step in to take the place of HPV-16 and HPV-18, the editorialists say, as well as to gauge the vaccine's overall clinical benefit and cost-effectiveness.

SOURCE: Journal of the American Medical Association, February 28, 2007.