Study: Virus Hits 1 in 4 Women

Feb 28, 06:16 AM

Current Headlines: By Delthia Ricks, Newsday, Melville, N.Y.

Feb. 28--More than a quarter of girls and women between the ages of 14 and 59 are infected with the sexually transmitted virus that causes genital warts and cervical cancer, a prevalence that is higher than previous estimates, scientists have found in the largest study of its kind.

Cervical cancer and genital warts are caused by the human papillomavirus -- HPV -- which is estimated to be the most common sexually transmitted infection in the United States. But until the analysis reported today in the Journal of the American Medical Association, government health officials did not have as precise an estimate of how many women are affected as they do now.

Conducted by epidemiologists at the Centers for Disease Control and Prevention, the study found that 26.8 percent women throughout the country are infected with strains of the virus and that the largest proportion of carriers are between the ages of 20 and 24.

"We knew the prevalence of HPV would be high," said Dr. Eileen Dunne, a medical epidemiologist in the CDC's division of STD prevention, and lead investigator. "This study is the first of its kind to look at a representative sample of females in the United States. "

Earlier studies had estimated that 20 million people in the United States, both men and women, are infected with HPV. This one, however, also examined which HPV strain is most prevalent in the population.

"This is a very important study because it shows that more women are probably infected with HPV than we previously realized, and it's still an underestimation of strains that cause pathological problems," said Dr. Mary Fatehi, a gynecological oncologist, at Long Island College Hospital.

Dunne and her colleagues found that HPV infection increased with each year from age 14 to 24, then precipitously declined as women aged. Infection was most notable in some of the age groups targeted for the new HPV vaccine -- Gardasil -- developed by Merck & Co. The vaccine was approved by regulators last June.

However, CDC analysis found that only 3.4 percent of women in the study carried strains covered by the vaccine. There are dozens of HPV strains, not all of which cause cancer or genital warts. And even with the high-risk strains, most women clear the infection within two years. The vaccine protects against four strains of HPV.

Gardasil has been controversial among religious and anti-vaccine groups since its approval because opponents do not want states to require vaccination for school admission.

But Fatehi said even though a majority of carriers did not have the strains Gardasil protects against, that is not a reason to avoid vaccination.

"Keep in mind that this was a single study at a single point in time, a snapshot," Fatehi said yesterday.

The CDC study is based on vaginal swab tests of more than 1,900 women between 2003 and 2004.

"This study does not have estimates of those who will test positive at a future date," she said, explaining that it is impossible to know which of the numerous HPV strains will peak at any given time.

Despite a lower prevalence of strains covered by its vaccine, Merck said in a statement yesterday that it stands by the recommendation of a CDC advisory committee, which last year recommended the three-shot vaccine for girls and women nine to 26 years old. The vaccine is said to work best before girls become sexually active.

The American Cancer Society estimates that slightly more than 11,000 women will be diagnosed with cervical cancer this year and that more than 3,600 will die as a result of it.

-----

Copyright (c) 2007, Newsday, Melville, N.Y.

Distributed by McClatchy-Tribune Business News.

For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.

NYSE:MRK,