Two-Thirds of U.S. Adults May Carry HPV
But study finds only 4 of 103 people whose DNA was tested had the cancer-causing strain of the virus
By Robert Preidt
TUESDAY, May 20, 2014 (HealthDay News) -- About two-thirds of healthy American adults are infected with human papillomavirus (HPV), but only a few of the strains they carry are the high-risk types known to cause cancer, new research suggests.
Those high-risk HPV strains -- known as types 16 and 18 -- cause virtually all cervical cancers, according to the U.S. National Cancer Institute. They also cause most anal cancers and some vaginal, vulvar, penile and oral cancers. However, most infections with high-risk HPVs do not cause cancer, experts note.
For the study, investigators at the NYU Langone Medical Center in New York City analyzed tissue DNA samples that were collected from four areas -- skin, mouth, vagina and gut -- of 103 women and men, aged 18 to 80, and stored in a U.S. National Institutes of Health database. The researchers found that 69 percent of the adults were infected with one or more of 109 of 148 known strains of HPV.
However, only four of the adults had either of the two HPV types known to cause most cases of cervical cancer, some throat cancers and genital warts, according to the study authors.
Most of the HPV infections were detected in the skin (61 percent), followed by the vagina (41 percent), mouth (30 percent) and gut (17 percent). Of the 71 people infected with HPV, 59 percent had HPV in one organ, 31 percent had HPV in two organs, 10 percent had HPV in three organs, and none had HPV in all four organs.
The greatest number of HPV strains was found in the skin, where there were 80 types of HPV, including 40 found only in the skin. The second highest number of HPV strains was found in the vagina (43 types of HPV, with 20 exclusive to the vagina), followed by the mouth (33 HPV types, with five exclusive to the mouth), and the gut (six types of HPV, all of which were found in other organs).
The findings show that HPV infection is common and suggest that certain types of HPV may keep others in check and prevent them from spreading out of control, according to the researchers.