Study: Sexually active gay teens at high risk for HPV

Gay teenagers who’ve had at least four sexual partners are at increased risk of contracting human papillomavirus (HPV), a recent study published online in November in the The Journal of Infectious Diseases suggests.

Researchers in Australia tested 200 young gay men ages 16 to 20 for HPV and genital warts, and gave them a sexual history questionnaire. HPV, which previous research suggests is carried by most adult gay men, is usually cleared by the immune system, but can cause genital warts and anal cancer, as well as cervical cancer among women.

"In this study we found rates of anal infection increased rapidly with increasing numbers of partners with whom they have received anal sex," said Marcus Y. Chen, senior author of the study and associate professor in the School of Population and Global Health at the University of Melbourne in Australia. "The virus is presumably being transmitted from penis to anus."

One-third of men participating in the study tested positive for high-risk forms of the sexually transmitted virus, and 11 percent tested positive for two or more forms.

Men who had vaginal or anal sex were more likely to test positive for penile HPV, according to results published in the Journal of Infectious Diseases.

Among men who had never received anal sex, 10 percent tested positive for anal HPV. That compared to nearly half of those who said they'd had at least four anal sex partners.

The finding that some young men who reported never receiving anal sex tested positive for anal HPV suggests the virus can be transmitted in other ways, the authors write.

At least half of sexually active people get HPV at some point in their lives, according to the Centers for Disease Control and Prevention (CDC).

The CDC recommends boys and girls get vaccinated against HPV at age 11 or 12, before becoming sexually active. There are two versions of the HPV vaccine, one of which is available for boys.

The vaccine is very effective if given before a person is exposed to HPV, but provides "diminishing protection" after that, Dr. Ross D. Cranston told Reuters Health.

"Thus if there is a high rate of HPV acquisition, as we also see in girls, there is a lost opportunity to provide protection if the HPV vaccine is not given early," he said.

Cranston, who was not involved in the new study, directs the Anal Dysplasia Clinic and Research Program at the University of Pittsburgh Medical Center in Pennsylvania.

About 7,000 people in the U.S. will be diagnosed with anal cancer in 2013, according to the American Cancer Society. Rates are higher among gay men than heterosexual people, Chen noted.

Of the many types of the HPV virus, HPV 16 is most commonly associated with anal cancers.

Reuters