Hepatitis C virus transmission among HIV-infected men who have sex with men: Modeling the effect of behavioral and treatment interventions.

The incidence of hepatitis C virus(HCV) infections among HIV-infected men-who-have-sex- with-men(MSM) increased in recent years and is associated with high-risk sexual behavior. Behavioral interventions that target high-risk behavior associated with HCV transmission and treatment with direct-acting antivirals(DAAs) may prevent further HCV infections. We predicted the effect of behavioral and treatment interventions on HCV-incidence and -prevalence among HIV-infected MSM up to 2030 using a HCV transmission model parameterized with data from the Swiss HIV Cohort Study. We assessed behavioral interventions associated with further increase, stabilization and decrease in the size of the population with high-risk behavior. Treatment interventions included increase in treatment uptake and use of DAAs. If we assumed that without behavioral interventions high-risk behavior spread further according to the trends observed over the last decade, and that the treatment practice did not change, HCV-incidence converged to 10.7/100 person-years(py). All assessed behavioral interventions alone resulted in reduced HCV transmissions. Stabilization of high-risk behavior combined with increased treatment uptake and the use of DAAs reduced incidence by 77%(from 2.2 in 2015 to 0.5/100 py) and prevalence by 81%(from 4.8% in 2015 to 0.9%) over the next 15 years. Increasing treatment uptake was more effective than increasing treatment efficacy to reduce HCV-incidence and -prevalence. A decrease in high-risk behavior, led to a rapid decline in HCV-incidence, independent of treatment interventions. CONCLUSION Treatment interventions to curb the HCV epidemic among HIV-infected MSM are effective if high-risk behavior does not increase as it has during the last decade. Reducing high-risk behavior associated with HCV transmission would be the most effective intervention for controlling the HCV epidemic, even if this was not accompanied by an increase in treatment uptake or efficacy. This article is protected by copyright. All rights reserved