Declining prevalence of current HCV infection and increased treatment uptake among people who inject drugs: The ETHOS Engage study

Background: Evaluating trends in HCV treatment and prevalence is crucial for monitoring elimination. We evaluated the change in current infection and treatment among people who inject drugs (PWID) between 2018-2019 and 2019-2021.

Methods: ETHOS Engage is an observational cohort study of PWID attending drug treatment clinics and needle and syringe programs in Australia. Participant enrolment occurred over two periods, Wave 1 (May 2018-September 2019, 25 sites) and Wave 2 (November 2019-June 2021, 21 sites), with baseline questionnaire completion and point-of-care HCV RNA testing (Xpert® HCV Viral Load Fingerstick). Logistic regression was used to identify factors associated with current HCV infection and historic HCV treatment.

Results: 2,395 individuals were enrolled across the two recruitment waves (66% male, median age 43, 72% current opioid agonist therapy, and 65% injecting in the previous month). HCV prevalence decreased from 24% to 17% between 2018-2019 and 2019-2021, respectively (p=0.003). HCV treatment increased from 66% to 74% between 2018-2019 and 2019-2021, respectively (p<0.001). After adjusting, there was a reduction in current HCV infection in 2019-2021 (adjusted odds ratio [aOR] 0.62; 95% CI, 0.50, 0.77) compared to 2018-2019. Other factors associated with current infection included homelessness (aOR, 1.70; 1.26, 2.30), incarceration (vs. never; historic: aOR 1.69; 95%CI 1.31, 2.19; recent: aOR 1.85; 95%CI, 1.35, 2.54), and recently injecting drugs (vs. >12 months ago; previous month <daily: aOR 2.03; 95%CI, 1.37, 3.02; ≥daily: aOR 2.90; 95%CI, 1.94, 4.32).

Conclusion: The increase in HCV treatment and decrease in prevalence among PWID provides evidence of further progress towards HCV elimination; however, sub-populations may require additional support to enhance elimination.

Lay summary: PWID are a priority population to facilitate HCV elimination and temporal data are crucial to understand trends in HCV infection and treatment in this group. Among a cohort of PWID recruited during two different waves and in an era of unrestricted DAA therapy, prevalence of HCV infection decreased and the proportion who had received HCV treatment increased. Sub-populations of PWID-including people who are homeless, people who have been incarcerated, people who frequently inject drugs, younger people, women, and people not engaged in OAT-may require additional support to enhance HCV elimination efforts.