HIV-positive men who have sex with men (MSM) acquire new anal infections with cancer-associated strains of human papillomavirus (HPV) at high rates, aidsmap reports. Publishing their findings in the journal AIDS, investigators in San Francisco conducted a prospective study of MSM whom they recruited between 1998 and 2000 and followed for at least two years.

In addition to responding to questions about their recent sexual behavior, the study participants received swabs every six months to detect anal HPV infection. Seventy-five percent reported having anal or genital warts in the past, and 92 percent had some form of anal HPV at the beginning of the study. Seventy-eight percent of the men had low- or high-grade precancerous anal cell changes at the study's outset.

The annual rate of new anal infections—also known as the incidence—with any type of HPV was 21.3 per 100 person-years, while the incidence for cancer-linked HPV strains was 13.3 per 100 person-years. The two types of HPV most associated with anal cancer were also the most commonly acquired each year: HPV 18 had an incidence rate of 3.7 per 100 person-years, while HPV 16's rate was 3.5 per 100 person-years.

Receptive anal intercourse was associated with a significantly raised risk of anal HPV infection, both in terms of how often the men practiced the sexual act and how many recent partners they had. Receptive oral-anal sex, known as rimming, was also a risk factor.

To read the aidsmap story, click here.

To read the study abstract, click here.