The hepatitis C virus epidemics in key populations (including people who inject drugs, prisoners and MSM): the use of direct-acting antivirals as treatment for prevention.

PURPOSE OF REVIEW: The burden of hepatitis C virus (HCV) is high among people who inject drugs (PWID) and prisoners, and increasing among HIV-infected MSM, who are key populations for HCV transmission in high-income countries and may also play a role in many in low- and middle-income countries. There is an increasing interest in the use of HCV antiviral treatment for prevention in these populations.

RECENT FINDINGS: Numerous theoretical modelling studies have explored the potential impact of HCV treatment for prevention among PWID in a range of global settings, generally finding that modest and achievable levels of HCV treatment, especially with interferon-free direct-acting antiviral therapy (IFN-free DAAs), could substantially reduce HCV chronic prevalence among PWID within the next 10-20 years. In addition, modelling studies have shown HCV testing and treatment in prison (including prevention benefits) could be cost-effective if continuity of care is ensured, or HCV treatments are shortened with DAAs. Modelling work among HIV-infected MSM has shown that further HCV treatment scale-up is likely required despite high treatment rates in this population. However, no empirical studies have explored whether HCV treatment can reduce HCV prevalence and prevent onwards transmission among those at risk of transmission.

SUMMARY: HCV treatment for key populations such as PWID, prisoners and MSM could become an important HCV prevention intervention, especially in the IFN-free DAA era. However, there is an urgent need to test these hypotheses through empirical studies.