Sexual transmission of hepatitis C virus among gay and bisexual men: a systematic review.

A systematic review was performed on the evidence of sexual transmission of hepatitis C virus (HCV) in gay and bisexual men (GBM). Studies conducted in industrialised countries and published in English from 2000 to 2015 with data on HCV in GBM were included. Pooled estimates of prevalence and incidence of HCV infection were stratified by study settings and participants' HIV status using random effect models. Case-series reports were summarised descriptively. Of the 38 cross-sectional studies, the pooled HCV prevalence was substantially higher in HIV-positive men (8.3%, 95% CI: 6.7-9.9) than in HIV-negative men (1.5%, 95% CI 0.8-2.1), and higher in those who reported injecting drug use (34.8%, 95% CI 26.9-42.7) than in those who did not (3.5%, 95% CI 2.4-4.5). Of the 16 longitudinal studies, the pooled HCV incidence was markedly higher in clinic-based (7.0 per 1000 person-years, 95% CI 4.6-9.5) than in community-based (1.4 per 1000 person-years, 95% CI 0.7-2.1) studies, and in HIV-positive men (6.4 per 1000 person-years, 95% CI 4.6-8.1) than in HIV-negative men (0.4 per 1000 person-years, 95% CI 0-0.9). Since the early 2000s, 15 case-series reports increasingly pointed to the importance of sexual transmission of HCV in mainly HIV-positive men. Injecting drug use remained the major transmission route of HCV in GBM. Receptive condomless intercourse and concurrent ulcerative sexually transmissible infections are likely drivers that facilitated HCV sexual transmission in HIV-positive men. HCV incidence remains very low in HIV-negative GBM.