Impact of Antiviral Therapy Scale‐Up Among People Who Inject Drugs in Scotland: Regional Evidence of Hepatitis C Virus Elimination

BACKGROUND: Expansion of highly effective direct-acting antiviral (DAA) treatment for people who inject drugs (PWID) is regarded as essential to achieve hepatitis C virus (HCV) elimination. A decade since the introduction of DAA treatment, we aimed to assess its roll-out and associated impact in reducing HCV prevalence among PWID in Scotland, as part of a treatment-as-prevention (TasP) strategy. METHODS: National bio-behavioural surveys of PWID (recruited at services providing injecting equipment) between 2010 and 2023 (N = 16 973), involving a questionnaire and blood spot sample (tested for HCV-antibodies and HCV-RNA), were used to examine treatment uptake and HCV viraemia prevalence (overall and among those with antibodies) for Tayside, Greater Glasgow & Clyde (GGC), and Rest of Scotland (RoS). We used a flexible Bayesian logistic regression model to estimate HCV prevalence and probability of having achieved an 80% reduction in HCV prevalence since 2015. RESULTS: Between 2015-16 and 2022-23, uptake of DAAs (ever) increased 2.7-, 5.6- and 4.5-fold to 95%, 78% and 76% in Tayside, GGC and RoS, respectively. Over this period, observed viraemia prevalence declined to 4%, 16% and 15% (involving 86%, 65% and 53% decline) in Tayside, GGC and RoS, respectively. In Tayside, modelled viraemia prevalence among those with antibodies declined from 62% in 2015 to 11% in 2023, with a 53% probability that the WHO proxy target of an 80% reduction in HCV prevalence was met. CONCLUSION: Our study provides real-world evidence for TasP, demonstrating that HCV elimination among PWID is feasible through community-wide scale-up of DAAs and population-level monitoring surveys.