It is not known to what extent a reported increase in hepatitis C virus incidence among HIV-positive men who have sex with men (MSM) is due to sexual transmission, noted Dr. Fengyi Jin, of the National Center in HIV Epidemiology and Clinical Research, and colleagues. In the current study, the authors described HCV prevalence, incidence, and risk factors for two cohorts of MSM with or without HIV.
Both groups were recruited using community-based strategies. The men were interviewed face-to-face each year and asked to report injecting drug use, sexual activity, and other behaviors that might involve contact with blood. From 2001 to 2007, the participants were offered HCV screening.
At baseline, HCV prevalence was 1.07 percent among HIV-negative MSM and 9.39 percent among HIV-positive MSM. In both groups, screening HCV-positive was strongly associated with a history of injection drug use (odds ratio=56.18, 95 percent confidence interval 12.55 to 251.5 in HIV-negative, and OR=24.46, 95 percent CI 5.44 to 110.0 in HIV-positive).
Among the HIV-negative MSM, five HCV infections occurred during 4,412.1 person-years of follow-up, for an incidence of 0.11 per 100 person-years (95 percent CI 0.03 to 0.26). Just one seroconverter reported injection drug use (IDU). Of the five, four reported sexual contact with HIV-positive male partners, and two had incident ulcerative sexually transmitted infection. In the HIV-positive cohort, none seroconverted over 238.1 person-years of follow-up (97.5 percent CI zero to 1.54, single-sided).
"HCV prevalence was almost 10 times higher in HIV-positive homosexual men," the authors noted. "Although incident HCV infection was uncommon in both cohorts, cases of non-IDU-related transmission did occur, possibly linked to sexual contact with HIV-positive men," they concluded.