Quarter of US women infected with cervical cancer virus

About a quarter of females in the United States aged 14 to 59 may have the sexually transmitted infection human papillomavirus, which is linked to cervical cancer, according to research published Tuesday.

"Our study provides the first national estimate of prevalent HPV infection among females aged 14 to 59 years in the United States," said the team of scientists led by Eileen Dunne of the federal Centers for Disease Control and Prevention, writing in an article in the
Journal of the American Medical Association dated February 28.

HPV is the most commonly sexually transmitted infection in the United States.

"Our data indicate that the burden of prevalent HPV infection among women was higher than previous estimates," they wrote.

The most virulent types of HPV can cause cervical, anal and other genital cancers. HPV types 16 and 18 are responsible for about 70 percent of cervical cancers worldwide, according to background information in the article.

The study was based on DNA testing on 2,026 self-collected vaginal swabs among females aged 14 to 59 participating in the National Health and Nutrition Examination Survey in 2003-2004.

Nearly 27 percent of the samples tested positive for HPV DNA.

The principal risk factors cited by the scientists were age, marital status and increasing numbers of sexual partners.

The study comes amid an uproar about an HPV vaccine developed by the German pharmaceuticals Merck which targets young teenaged girls.

The Merck vaccine is effective against the four most common types of HPV and was approved by the US Food and Drug Administration in June 2006.

The vaccine is aimed primarily at girls aged nine to 13 because, to be highly effective, it should be administered before the first sexual relations.

But Merck was forced to stop lobbying on behalf of the vaccine last week in the face of opposition from religious groups that promote sexual abstinence and critics of the huge profits reaped by major drug firms.