Sexual Transmission of Hepatitis C Happens Through Blood, Not Semen, in Gay Men With HIV, Study Says

Sexual transmission of hepatitis C (HCV) has been documented since 2000 among gay, HIV-positive men in several major cities, including Amsterdam, Berlin, London and New York. The sexual practice of fisting has been particularly associated with the risk of getting HCV, but one key question has remained unanswered: Is HCV being transmitted only through blood during these sex acts, or is it potentially being transmitted through semen?

The answer, according to a recent study by German researchers, appears to be that HCV is only transmitted through blood. The study, presented at the European AIDS Conference in Cologne, Germany, and reported by aidsmap.com, involved 34 HIV/HCV coninfected gay men and 67 age-matched HIV-positive (HCV-negative) men. Most of the men said they had unprotected anal sex, and around 50 percent of the men said they had received fisting. Injection drug use -- long thought of as the major risk factor for HCV transmission -- was not reported by any of the men.

An analysis by the investigators found that two risk factors in particular were significantly associated with the sexual transmission of HCV: receptive fisting and rectal bleeding during sex. Also associated with sexual HCV transmission (albeit less so) was drug use during group sex. These findings led the researchers to conclude that HCV was being transmitted via blood, rather than semen, during sex.

As aidsmap.com reports, however, some attendees at the conference were skeptical of the study results. One noted that sexual transmission of HCV in London has been seen in men who did not report any participation in fisting. In addition, HCV itself is sometimes found in semen, and men who are HIV/HCV coinfected tend to have HCV in their semen more often than men who have HCV but not HIV, according to a report from Canadian AIDS Treatment Information Exchange.

Nonetheless, the study authors stand by their findings, which are only the latest to link HCV transmission risk among HIV-positive gay men to more violent sexual acts that can cause bleeding, such as fisting. (A study in 2006, also reported by aidsmap.com, noted that fisting seemed to play a key role in HCV transmission among gay men with HIV.)