Background: Prospective characterization of hepatitis C virus (HCV) transmission in both human immunodeficiency virus (HIV)-infected and -uninfected men who have sex with men (MSM) over the entire HIV epidemic has not been comprehensively conducted.
Methods: To determine the trends in and risk factors associated with incident HCV in MSM since 1984, 5310 HCV antibody (anti-HCV)-negative MSM in the Multicenter AIDS Cohort Study were prospectively followed during 1984-2011 for anti-HCV seroconversion.
Results: During 55 343 person-years (PYs) of follow-up, there were 115 incident HCV infections (incidence rate, 2.08/1000 PYs) scattered throughout the study period. In a multivariable analysis with time-varying covariates, older age (incidence rate ratio [IRR], 1.40/10 years, P < .001), enrollment in the later (2001-2003) recruitment period (IRR, 3.80, P = .001), HIV infection (IRR, 5.98, P < .001), drinking >13 alcoholic drinks per week (IRR, 1.68, P < .001), hepatitis B surface antigen positivity (IRR, 1.68, P < .001), syphilis (IRR, 2.95, P < .001), and unprotected receptive anal intercourse with >1 male partner (IRR, 3.37, P < .001) were independently associated with incident HCV. Among HIV-infected subjects, every 100 cell/mm(3) increase in CD4 count was associated with a 7% (P = .002) decrease in the HCV incidence rate up to a CD4 count of 500 cells/mm(3), whereas there was no association with highly active antiretroviral therapy.
Conclusions: The spread of HCV among both HIV-infected and -uninfected MSM in the United States has been ongoing since the beginning of the HIV epidemic. In HIV-infected men with <500 CD4(+) T cells, the HCV incidence rate was inversely proportional to CD4 T-cell count.
Keywords: MSM; incident HCV; sexual transmission.