Patterns of HCV transmission in HIV-infected and HIV-negative men having sex with men

BACKGROUND: Sexually transmitted acute hepatitis C virus (HCV) infections (AHIs) have been mainly described in human immunodeficiency virus (HIV)-infected men who have sex with men (MSM). Cases in HIV-negative MSM are scarce. We describe the epidemic of AHI in HIV-infected and HIV-negative MSM in Lyon, France. METHODS: All cases of AHI diagnosed in MSM in Lyon University Hospital from 2014 to 2017 were included. AHI incidence was determined in HIV-infected and in preexposure prophylaxis (PrEP)-using MSM. Transmission clusters were identified by construction of phylogenetic trees based on HCV NS5B (genotype 1a/4d) or NS5A (genotype 3a) Sanger sequencing. RESULTS: From 2014 to 2017, 108 AHIs (80 first infections, 28 reinfections) were reported in 96 MSM (HIV-infected, 72; HIV-negative, 24). AHI incidence rose from 1.1/100 person-years (95 confidence interval [CI], 0.7-1.7) in 2014 to 2.4/100 person-years (95 CI, 1.1-2.6) in 2017 in HIV-infected MSM (P = .05) and from 0.3/100 person-years (95 CI, 0.06-1.0) in 2016 to 3.4/100 person-years (95 CI, 2.0-5.5) in 2017 in PrEP users (P < .001). Eleven clusters were identified. All clusters included HIV-infected MSM; 6 also included HIV-negative MSM. All clusters started with ≥1 HIV-infected MSM. Risk factor distribution varied among clusters. CONCLUSIONS: AHI incidence increased in both HIV-infected and HIV-negative MSM. Cluster analysis suggests initial transmission from HIV-infected to HIV-negative MSM through chemsex and traumatic sexual practices, leading to mixed patterns of transmission regardless of HIV status and no overlap with the general population.