Transmission of hepatitis C virus among men who have sex with men has been occurring since early in the HIV epidemic, and the rates of infection are higher among those with HIV, according to data published in Clinical Infectious Diseases.
“HCV transmission among MSM has been ongoing for at least 3 decades in both HIV-infected and HIV-uninfected men,” Chloe Thio, MD, associate professor of medicine at Johns Hopkins University, told Infectious Disease News. “Recent reports of HCV in MSM suggest that this is an emerging problem, so it was unexpected to find that transmission has been occurring at relatively high rates for several decades.”
From 1984 to 2011, the researchers prospectively followed 5,310 MSM who were enrolled in the Multicenter AIDS Cohort Study. The cohort included men with HIV and men at risk for HIV. All of the men tested negative for HCV antibody within 2 years of enrollment and had another HCV antibody test at one or more follow-up visits through Sept. 30, 2011. Incident HCV infection was defined as a positive HCV antibody test at two or more follow-up visits.
The cohort was followed for a median of 7.1 years and had 55,343 person-years of follow-up. During this time, there were 115 incident HCV infections, with an incidence rate of 2.08 per 1,000 person-years (95% CI, 1.73-2.49). Among men with HIV, the incidence rate was 4.22, nearly 8.5-fold higher than the 0.5 incident rate for men without HIV.
In a multivariable analysis, factors associated with an increased risk for HCV included older age, HIV infection, being positive for hepatitis B surface antigen, history of injection drug use, drinking more than 13 drinks a week, syphilis and having unprotected receptive anal intercourse with multiple partners in the prior 6 months. Among men with HIV, the risk for HCV decreased as CD4+ counts increased from 0 cells/mm3 to 500 cells/mm3.
“These data emphasize the importance of checking for HCV in all MSM regardless of whether they are still sexually active, since they could have been infected decades ago,” Thio said. “In addition, counseling patients about the increased risk for receptive partners should also occur.”
Thio said that future research questions should address whether outcomes of the incident infections in MSM have changed over time. In addition, based on the finding that lower CD4+ counts are associated with increased risk for HCV, it is important to understand how immunosuppression from HIV affects acquisition of HCV.
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Chloe Thio, MD, can be reached at: Department of Medicine, Johns Hopkins University, 855 N. Wolfe St., Baltimore, MD, 21205.
Disclosure: Thio reports no relevant financial disclosures.