One in four American women infected with HPV

In the first comprehensive study of a sexually transmitted disease that can cause cervical cancer, it has been found that one in four American women age 14 to 59 are infected with the human papillomavirus (HPV).

The findings are in line with preliminary forecasts, but the latest study by the Centers for Disease Control and Prevention (CDC) suggests that about 44 percent of those women are between the ages 20 to 24.

The study also showed that the number of young teens infected with the virus has declined.

Dr. Eileen Dunne and colleagues from the CDC used data from a nationally representative group of 1,921 girls and women ages 14 to 49 who provided vaginal swabs in 2003 and 2004, and the researchers found that 26.8 percent were infected with some type of the virus.

According to Dunne that rate translates to a total of 24.9 million U.S. girls and women, and it is a highly prevalent infection, of which many women are at risk.

Dunne says the findings highlight the importance of cervical cancer screening.

HPV is the most common sexually transmitted infection in the United States and high-risk HPV types can cause cervical, anal, penile and other genital cancers, while low-risk types can cause genital warts.

Among those aged 14 to 19, 24.5 percent were infected.

The researchers say when this is added to the 44.8 percent of those 20 to 24 who were infected, this translates to 7.5 million girls and women age 14 to 24 infected, higher than a previous estimate of 4.6 million.

The study says that 20 million Americans are probably infected with some strain of human papillomavirus or HPV and just over 3 percent of those women infected had the strain of HPV that can lead to cervical cancer.

This evidence suggests that HPV infection is more common than previously thought, particularly among younger age groups.

HPV infects about half of sexually active adults at some time, but usually is harmless and 90 percent of infections clear up within two years.

The virus can however cause abnormal cells in the cervix lining that can turn cancerous.

Cancer of the cervix kills about 300,000 women worldwide annually, including about 4,000 in the United States.

Last June the FDA approved the vaccine Gardasil for girls and young women ages 9 to 26 and the CDC recommends it for routine use for girls ages 11 to 12.

Gardasil is delivered in three doses over a six month period, and targets four HPV types thought to be responsible for more than 70 percent of cervical cancer cases and 90 percent of genital warts cases.

The study is published in the Journal of the American Medical Association.