Epidemiological trends in HCV transmission and prevalence in the Viennese HIV+ population.

Background & Aims Human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfection is common in people who inject drugs (PWIDs). Recently, 'high-risk' behaviour among men who have sex with men (MSM) has emerged as another main route of HCV transmission. We analysed temporal trends in HCV epidemiology in a cohort of Viennese HIV+ patients. Methods Hepatitis C virus parameters were recorded at HIV diagnosis (baseline [BL]) and last visit (follow-up [FU]) for all HIV+ patients attending our HIV clinic between January 2014 and December 2016. Proportions of HIV+ patients with anti-HCV(+) and HCV viraemia (HCV-RNA(+)) at BL/FU were assessed and stratified by route of transmission. Results In all, 1806/1874 (96.4%) HIV+ patients were tested for HCV at BL. Anti-HCV(+) was detected in 93.2% (276/296) of PWIDs and in 3.7% (31/839) of MSM. After a median FU of 6.9 years, 1644 (91.0%) patients underwent FU HCV-testing: 167 (90.3%) of PWIDs and 49 (6.7%) of MSM showed anti-HCV(+). Among 208 viraemic HCV-RNA(+) patients at BL, 30 (14.4%) had spontaneously cleared HCV, 76 (36.5%) achieved treatment-induced eradication and 89 (42.8%) remained HCV-RNA(+) at last FU. Among 1433 initially HCV-naive patients, 45 (3.5%) acquired de-novo HCV infection (11.1% PWIDs/80.0% MSM; incidence rate (IR) 0.004%; 95% confidence interval [CI] 0.0%-0.022%) and 14 had HCV reinfections (85.7% PWIDs/14.3% other; IR 0.001%; 95% CI 0.0%-0.018%) during a median FU of 6.7 years (interquartile range 7.4). Conclusion Hepatitis C virus testing was successfully implemented in the Viennese HIV(+) patients. Anti-HCV(+) prevalence remained stable in HIV+ PWIDs but almost doubled in HIV+ MSM. De-novo HCV infection occurred mostly in MSM, while HCV reinfections were mainly observed in PWIDs. HCV treatment uptake was suboptimal with 42.8% remaining HCV-RNA(+) at FU.