German Study Sheds Further Light on Hepatitis C Sexual Transmission among HIV Positive Gay Men

		SUMMARY: The ongoing outbreak of apparently sexually transmitted hepatitis C virus (HCV) infection among men who have sex with men is associated with "rough sex" practices such as fisting, but not with unprotected anal intercourse, indicating that blood rather than semen is the likely route of transmission, according to data presented last week at the 12th European AIDS Conference (EACS 2009) in Cologne.

By Liz Highleyman

Starting around 2000, clinicians in cities in the U.K. and Europe began reporting outbreaks of acute HCV infection among HIV positive gay and bisexual men, which were associated with sexual risk factors and reflected social and sexual networks. Such outbreaks have since been reported in Australia and the U.S.

Various epidemiological studies have linked these outbreaks to a variety of sexual and non-injection drug use practices, but the data has not been entirely consistent.

To clarify risk factors associated with HCV transmission in this population, researchers with the Study Group on Sexual Risk Factors for Hepatitis C conducted a case-control analysis of 34 HIV/HCV coinfected men who have sex with men and 67 age-matched HIV monoinfected men recruited at the University of Bonn between 2006 and 2008. None of the men reported injection drug use.

Results

	Most of the men reported unprotected anal intercourse.
	About 50% reported receptive fisting.
	In a multivariate analysis, the following factors were significantly associated with hepatitis C infection:
	Receptive fisting without gloves; Rectal bleeding during sex; Group sex; Nasal drug use.
	However, unprotected anal sex that did not occur in the context of these other practices was not an independent risk factor for HCV transmission.
	Other factors not significantly associated with HCV infection in this analysis (though they have been in other studies) included:
	Use of sex toys; Higher number of sex partners; History of other sexually transmitted infections.

Based on these results, the investigators concluded that blood -- rather than semen -- is the probably route of HCV transmission in HIV positive men who have sex with men.

The researchers noted that HCV sexual transmission appeared to be occurring among men who practice serosorting, or engaging in unprotected sex with others of the same HIV status. They also suggested that insertive partners ("tops") -- who may not be HCV-infected themselves -- might be acting as "vectors" to spread the virus among receptive partners ("bottoms"), which could occur even if condoms or gloves were used but not changed between partners. Furthermore, blood contamination of lubricants and sharing equipment to snort drugs could also play a role.

These findings may help explain the discrepancy between the relatively high rate of HCV sexual transmission within this population and the very low rates (typically 0%-5%) observed in epidemiological studies of stable heterosexual couples.

11/20/09

Reference
AJ Schmidt, M Vogel, I Krznaric, and others (Study Group on Sexual Risk Factors for Hepatitis C). The trouble with bleeding: why do HIV-positive gay men get hepatitis C? 12th European AIDS Conference. Cologne, Germany. November 11-14, 2009. Abstract BPD1/7.