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We assessed the predictive capacity of the HCV-MOSAIC risk score, originally developed for primary early HCV infection, as a screening tool for HCV reinfection in 103 men who have sex with men (MSM) with HIV using data from the MOSAIC cohort, including MSM with HIV/HCV-coinfection who became reinfected (cases, n = 27) or not (controls, n = 76) during follow-up. The overall predictive capacity of the score was assessed using the area under the receiver operating characteristic (AUROC) curve. The effects of covariates on the receiver operating characteristic (ROC) curve were assessed using parametric ROC regression. The score cut-off validated for primary early infection (≥2.0) was used, from which the sensitivity and specificity were calculated. The AUROC was 0.74 (95% confidence interval (CI) = 0.63–0.84). Group sex significantly increased the predictive capacity. Using the validated cut-off, sensitivity was 70.4% (95%CI = 49.8–86.2%) and specificity was 59.2% (95%CI: 47.3–70.4%). External validation from a cohort of 25 cases and 111 controls, all MSM with HIV, resulted in a sensitivity of 44.0% (95%CI = 24.4–65.1) and specificity of 71.2% (95%CI = 61.8–79.4). The HCV-MOSAIC risk score may be useful for identifying individuals at risk of HCV reinfection. In sexual health or HIV-care settings, this score could help guide HCV-RNA testing in MSM with a prior HCV infection. [ABSTRACT FROM AUTHOR]

Introduction: Exploration of sexual and drug use behaviours following treatment for recent hepatitis C virus (HCV) is limited. This analysis modelled behavioural trajectories following treatment for recent HCV and assessed reinfection. Methods: Participants treated for recent HCV in an international trial (enrolled 2017–2019) were followed at 3‐monthly intervals for up to 2 years to assess longitudinal behaviours. Population‐averaged changes were assessed using generalized estimating equations. Distinct behavioural trajectories were identified using group‐based trajectory modelling. HCV reinfection incidence was calculated using person‐years (PY) of observation. Results: During the follow‐up of 212 participants (84% gay and bisexual men [GBM]; 69% HIV; 26% current injecting drug use [IDU]), behavioural trajectories for IDU and stimulant use (past month) did not change. However, population‐averaged decreases in the likelihood of daily IDU (adjusted odds ratio [AOR] 0.83; 95% CI 0.72, 0.95) and opioid use (AOR 0.84; 95% CI 0.75, 0.93) were observed. Among GBM, behavioural trajectories for chemsex did not change. Population‐averaged decreases in condomless anal intercourse with casual male partners (CAI‐CMP) (AOR 0.95; 95% CI 0.90, 0.99) and group‐sex (AOR 0.86; 95% CI 0.80, 0.93) were observed, but masked distinct trajectories. While a proportion had a decreased probability of CAI‐CMP (23%) and group‐sex (59%) post‐treatment, a substantial proportion retained a high probability of these behaviours. High HCV reinfection incidence was observed for the sustained high probability IDU (33.0/100 PY; 95% CI 17.7, 61.3) and chemsex (23.3/100 PY; 95% CI 14.5, 37.5) trajectories. Conclusions: Limited sexual and drug use behavioural change was observed following treatment for recent HCV, supporting access to surveillance and (re)treatment. [ABSTRACT FROM AUTHOR]

Following the discovery of hepatitis C virus (HCV) in 1989, 3 decades of basic, translational, and clinical research culminated in the development of direct-acting antiviral (DAA) therapy—curative oral treatment for HCV infection. The availability of DAA therapy revolutionized HCV clinical management, including acute (duration of infection <6 mo) and recent (duration of infection <12 mo) infection. Several DAA regimens, including the contemporary pan-genotypic combinations of sofosbuvir-velpatasvir and glecaprevir-pibrentasvir, have been shown to be safe and effective among people with acute and recent HCV infection, highlighting their potential in an HCV controlled human infection model. This article describes the natural history and management of acute and recent HCV infection in the era of DAA therapy and outlines a strategy for use of DAA therapies in the setting of an HCV controlled human infection model. [ABSTRACT FROM AUTHOR]

Virological failure occurs in a small proportion of people treated for hepatitis C virus (HCV) with direct‐acting antiviral (DAA) therapies. This study assessed retreatment for virological failure in a large real‐world cohort. REACH‐C is an Australian observational study (n = 10,843) evaluating treatment outcomes of sequential DAA initiations across 33 health services between March 2016 to June 2019. Virological failure retreatment data were collected until October 2020. Of 408 people with virological failure (81% male; median age 53; 38% cirrhosis; 56% genotype 3), 213 (54%) were retreated once; 15 were retreated twice. A range of genotype specific and pangenotypic DAAs were used to retreat virological failure in primary (n = 56) and tertiary (n = 157) settings. Following sofosbuvir/velpatasvir/voxilaprevir availability in 2019, the proportion retreated in primary care increased from 21% to 40% and median time to retreatment initiation declined from 294 to 152 days. Per protocol (PP) sustained virological response (SVR12) was similar for people retreated in primary and tertiary settings (80% vs 81%; p = 1.000). In regression analysis, sofosbuvir/velpatasvir/voxilaprevir (vs. other regimens) significantly decreased likelihood of second virological failure (PP SVR12 88% vs. 77%; adjusted odds ratio [AOR] 0.29; 95%CI 0.11–0.81); cirrhosis increased likelihood (PP SVR12 69% vs. 91%; AOR 4.26; 95%CI 1.64–11.09). Indigenous Australians had lower likelihood of retreatment initiation (AOR 0.36; 95%CI 0.15–0.81). Treatment setting and prescriber type were not associated with retreatment initiation or outcome. Virological failure can be effectively retreated in primary care. Expanded access to simplified retreatment regimens through decentralized models may increase retreatment uptake and reduce HCV‐related mortality. [ABSTRACT FROM AUTHOR]

People living with HIV (PLHIV) are a priority population to receive hepatitis C virus (HCV) screening and treatment. We aimed to characterize the HCV care cascade among PLHIV between 2010 and 2018 and to compare HCV testing and treatment uptake pre‐ and post‐availability of direct‐acting antivirals (DAAs) in New South Wales (NSW), Australia. Records of all HCV notifications (1993–2017) were linked to HIV notifications, deaths, hospitalizations, incarcerations, opioid agonist therapy, HCV RNA testing and treatment databases. Numbers and proportions were calculated for all stages of the care cascade and factors associated with HCV testing, and DAA treatment uptake were evaluated using logistic regression. From 383 individuals with HCV notification (2009–2017), 349 (91%) were ever HCV RNA tested, 285 (74%) had an indicator of chronic HCV infection, and from those eligible for treatment, 210 (74%) received HCV treatment. HCV testing was recorded for 85% pre‐DAA era and reached a cumulative proportion of 90% post‐DAA while treatment uptake had a 10‐fold increase from 7% pre‐ to 73% post‐DAA era. Younger age (adjusted odds ratio [aOR] 0.98; 95% CI 0.96–0.99), female gender (aOR 1.87; 95% CI 1.10–3.19), and rural region residence at notification (aOR 1.56; 95% CI 1.03–2.36) were associated with not receiving HCV testing. No identified factor was associated with not receiving treatment post‐DAA era. Removing barriers to HCV testing, expanding treatment to a variety of settings and continuous education and harm reduction are essential to achieve HCV elimination among PLHIV in Australia. [ABSTRACT FROM AUTHOR]

Shortened duration therapy for acute and recent HCV infection has been shown to be highly effective in several small non-randomised studies with direct-acting antiviral regimens; however, large randomised studies are lacking. REACT was an NIH-funded multicentre international, open-label, randomised, phase IV non-inferiority trial examining the efficacy of short course (6-week) vs. standard course (12-week) therapy with sofosbuvir-velpatasvir for recent HCV infection (estimated duration of infection ≤12 months). Randomisation occurred at week 6. The primary endpoint was sustained virological response 12 weeks after treatment end (SVR12) in the intention-to treat (ITT) population. A total of 250 participants were due to be enrolled, but on advice of the data safety and monitoring board the study was halted early. The primary analysis population consisted of 188 randomised participants at termination of study enrolment; short arm (n = 93), standard arm (n = 95). Ninety-seven percent were male and 69% HIV positive. ITT SVR12 was 76/93, 81.7% (95% CI 72.4–89.0) in the short arm and 86/95, 90.5% (95% CI 82.7–95.6) in the standard arm. The difference between the arms was -8.8 (95% CI -18.6 to 1.0). In modified ITT analysis, wherein non-virological reasons for failure were excluded (death, reinfection, loss to follow-up), SVR12 was 76/85, 89.4% (95% CI 80.8–95.0) in the short arm and 86/88, 97.7% in the standard arm (95% CI 92.0–99.7; difference -8.3%, p = 0.025). In this randomised study in recent HCV infection, a 6-week course of sofosbuvir-velpatasvir did not meet the criteria for non-inferiority to standard 12-week therapy. In this randomised trial, 188 people with recently acquired hepatitis C infection were randomly assigned to treatment using either a short 6-week course (93 people) or standard 12-week course (95 people) of the hepatitis C treatment sofosbuvir/velpatasvir. There were 9 cases of relapse after treatment with the short course and 2 following the standard course. A shortened course of 6-week therapy for hepatitis C infection appeared to be less effective than a standard 12-week course in people with recently acquired hepatitis C infection. NCT02625909. [Display omitted] • REACT is a randomised study of short course DAA therapy for recently acquired HCV. • 188 participants were treated with either 6 or 12 weeks sofosbuvir/velapatasvir. • The study population was predominantly cis-male and included a high proportion living with HIV. • The study was stopped early due to the high rate of virological relapse in the short course arm. • Six weeks of sofosbuvir/velapatasvir cannot be considered non-inferior to 12 weeks. [ABSTRACT FROM AUTHOR]

Hepatitis C virus (HCV) prevalence is high among people living with HIV co-infected with HCV, people who inject drugs, men who have sex with men and inmates in correctional settings. The barriers to eliminate HCV among these key populations include diagnosis challenges, lack of awareness, discrimination and stigmatization. In addition, scaling up of HCV treatment has been a challenge in Asia–Pacific with the lack of national policies, targets and unavailability of appropriate direct-acting antivirals regimens. In order to achieve HCV micro elimination within these high-risk populations, novel strategies to improve the cascade of care from diagnosis to treatment with direct-acting antivirals, complemented by behavioral change interventions, harm reduction services for people who inject drugs, civil society led advocacy and policies from the government, will be necessary. There are limited data on HCV in Asia. Elimination of HCV is possible by using the micro-elimination technique. [ABSTRACT FROM AUTHOR]

Background The aim of this analysis was to calculate the incidence of hepatitis C virus (HCV) reinfection and associated factors among 2 clinical trials of HCV direct-acting antiviral treatment in people with recent injecting drug use or currently receiving opioid agonist therapy (OAT). Methods Participants who achieved an end-of-treatment response in 2 clinical trials of people with recent injecting drug use or currently receiving OAT (SIMPLIFY and D3FEAT) enrolled between March 2016 and February 2017 in 8 countries were assessed for HCV reinfection, confirmed by viral sequencing. Incidence was calculated using person-time of observation and associated factors were assessed using Cox proportional hazard models. Results Seventy-three percent of the population at risk of reinfection (n = 177; median age, 48 years; 73% male) reported ongoing injecting drug use. Total follow-up time at risk was 254 person-years (median, 1.8 years; range, 0.2–2.8 years). Eight cases of reinfection were confirmed for an incidence of 3.1/100 person-years (95% confidence interval [CI], 1.6–6.3) overall and 17.9/100 person-years (95% CI, 5.8–55.6) among those who reported sharing needles/syringes. Younger age and needle/syringe sharing were associated with HCV reinfection. Conclusions These data demonstrate the need for ongoing monitoring and improved strategies to prevent HCV reinfection following successful treatment among people with ongoing injecting drug use to achieve HCV elimination. Clinical Trials Registration NCT02336139 and NCT02498015. [ABSTRACT FROM AUTHOR]

The World Health Organization has set a goal to eliminate hepatitis C virus (HCV) infection as public health threat by 2030. Although the advent of highly effective and tolerable direct-acting antiviral therapy has paved the way for HCV elimination, most people with HCV infection remain undiagnosed and untreated globally, with striking disparities between high-income and low- to middle-income countries. Novel decentralized and cost-effective "test-and-treat" strategies are critically needed to identify the millions of people unaware of their status and link them to treatment. [ABSTRACT FROM AUTHOR]

Background This study investigated adherence and associated factors among people with recent injection drug use (IDU) or current opioid agonist therapy (OAT) and compared once-daily to twice-daily hepatitis C virus (HCV) direct-acting antiviral (DAA) therapy. Methods SIMPLIFY and D3FEAT are international, multicenter studies that recruited participants with recent IDU (previous 6 months; SIMPLIFY, D3FEAT) or current OAT (D3FEAT) between March 2016 and February 2017 in 8 countries. Participants received sofosbuvir/velpatasvir (once daily; SIMPLIFY) or paritaprevir/ritonavir/ombitasvir, dasabuvir (twice daily) ± ribavirin (D3FEAT) for 12 weeks administered in electronic blister packs. We evaluated overall adherence (proportion of prescribed doses taken) and nonadherence (<90% adherent) between dosing patterns. Results Of 190 participants, 184 (97%) completed treatment. Median adherence was 92%, with higher adherence among those receiving once-daily vs twice-daily therapy (94% vs 87%, P =.005). Overall, 40% of participants (n = 76) were nonadherent (<90% adherent). Recent stimulant injecting (odds ratio [OR], 2.48 [95% confidence interval {CI}, 1.28–4.82]), unstable housing (OR, 2.18 [95% CI, 1.01–4.70]), and twice-daily dosing (OR, 2.81 [95% CI, 1.47–5.36]) were associated with nonadherence. Adherence decreased during therapy. Sustained virologic response was high in nonadherent (89%) and adherent populations (95%, P =.174), with no difference in SVR between those who did and did not miss 7 consecutive doses (92% vs 93%, P =.897). Conclusions This study demonstrated high adherence to once- and twice-daily DAA therapy among people with recent IDU or currently receiving OAT. Nonadherence described did not impact treatment outcomes, suggesting forgiveness to nonadherence. [ABSTRACT FROM AUTHOR]

Background: Human immunodeficiency virus (HIV) infection leads to more rapid progression of hepatitis C virus (HCV)-related liver fibrosis, which could be linked to differences in the severity of liver inflammation among HIV/HCV co-infected individuals compared to HCV mono-infected individuals. This study assessed the association of HIV co-infection with pro-inflammatory and pro-fibrogenic cytokines and chemokines during recent HCV infection.Methods: Participants from the ATAHC study, a prospective cohort of recent HCV infection, with detectable HCV RNA at the time of acute HCV detection were included. Concentrations of 27 plasma cytokines and chemokines were measured by multiplex immunoassays and compared between those with, and without, HIV co-infection.Results: Out of 117 individuals with recent HCV infection included in analysis, 73 had HCV mono-infection and 44 had HIV/HCV co-infection. Individuals with HIV/HCV co-infection had significantly higher mean levels of eotaxin (1.79 vs. 1.62 log pg/mL; P < 0.001), monocyte chemotactic protein 1 (MCP-1; 2.10 vs. 1.98 log pg/mL; P < 0.001), and interferon-gamma inducible protein-10 (IP-10; 3.11 vs. 2.98 log pg/mL; P = 0.013). Linear regression analyses adjusting for age, alanine transaminase (ALT), HCV RNA levels, and assay run, higher eotaxin levels were independently associated with HIV/HCV co-infection (adjusted β: 0.12; 95%CI: 0.01, 0.24; P = 0.039). Higher MCP-1 levels were also independently associated with HIV/HCV co-infection in adjusted analysis (adjusted β: 0.11; 95%CI: 0.03, 0.18; P = 0.009).Conclusions: During recent HCV, those with HIV/HCV co-infection had a stronger pro-fibrogenic mediator profile compared to those with HCV mono-infection. These findings may provide a potential explanation for accelerated liver fibrosis in HIV/HCV co-infection.Trial Registration: Australian Trial in Acute Hepatitis C (ATAHC) study was registered with ClinicalTrials.gov registry on September 11, 2005. NCT00192569 . [ABSTRACT FROM AUTHOR]

Background: Estimates of the prevalence and disease burden of HIV/HCV coinfection in the Asia Pacific Region are uncertain. Methods: A systematic review of indexed (PubMed, Embase and Web of Science) and non-indexed cross-sectional and cohort studies (2009-2015) reporting HCV seroprevalence in HIV-positive adults living in the Asia Pacific region was performed. Pooled prevalence estimates were calculated with a DerSimonian-Laird random-effects model. Results: 39 studies from 10 countries in the Asia Pacific region comprising 89,452 HIV-positive individuals were included. In the high-income Asia Pacific region, HCV coinfection prevalence was 3.8% (95% confidence interval (CI): 3.1-4.5) in Singapore. In East Asia, HCV coinfection prevalence was 8.0% (95% CI: 6.4-9.8) in Hong Kong and 25.5% (95% CI: 17.5-34.4) in general HIV cohorts in China. In South Asia, HCV coinfection prevalence was 4.1% (95% CI: 1.7-7.3) in India and 42.6% (95% CI: 38.7-46.5) in Nepal. In Southeast Asia, HCV coinfection prevalence was 5.5% (95% CI: 4.9-6.1) in Cambodia, 5.3% (95% CI: 4.9-5.7) in Myanmar, and 5.1% (95% CI: 2.7-8.2) in Thailand, but higher in Vietnam (42.5%; 95% CI: 40.8-44.2) and Indonesia (17.9%; 95% CI: 15.0-20.9). The prevalence of HCV coinfection was higher in subpopulations of people who inject drugs (China 81.6%; 95% CI: 74.1-88.0; Nepal 80.8%; 95% CI: 76.4-84.9; Indonesia 81.6%; 95% CI: 71.1-90.3), former blood donors (China 82.9%; 95% CI: 73.9-90.3), and blood transfusion recipients (China 51.0%; 95% CI: 41.7-60.2). Conclusion: HCV coinfection prevalence within HIV populations is highly variable in the Asia Pacific region, between countries and at-risk populations. Enhanced epidemiological data is required to support scale-up of interferon-free HCV therapy. [ABSTRACT FROM AUTHOR]

Background: This study assessed the association of alanine-aminotransferase (ALT) and hepatitis C virus (HCV) RNA levels with pro-inflammatory and pro-fibrogenic cytokines and chemokines during acute HCV infection to provide further insight into the potential HCV immunopathogenesis. Methods: Participants in the ATAHC study, a prospective study of recent HCV infection, with detectable HCV RNA at the time of HCV detection were included. Plasma levels of 27 cytokines and chemokines were measured and their correlation with ALT and HCV RNA levels were assessed. Log10 transformed cytokines and ALT values were used in the analysis. Results: Among 117 individuals, the plasma levels of interferon-gamma inducible protein-10 (IP-10) and macrophage inflammatory protein-1beta (MIP-1ß) were positively correlated with ALT levels (IP-10: r = 0.42, P < 0.001; MIP-1ß: r = 0.29, P = 0.001) and HCV RNA levels (IP-10: rs = 0.44, P < 0.001; MIP-1ß: rs = 0.43, P < 0.001). Using linear regression, after adjusting for sex, age, infection duration, symptomatic infection, HIV co-infection, interferon-lambda rs12979860 genotype, HCV genotype, and assay run, higher ALT levels (ß = 0.20; 95 % CI: 0.07, 0.32; P = 0.002) and HCV RNA levels >400,000 IU/mL (vs. <8,500 IU/mL; ß = 0.16; 95 % CI: 0.03, 0.28; P = 0.014) were independently associated with higher IP-10 levels. HCV RNA levels >400,000 IU/mL (vs. <8,500 IU/mL; ß = 0.16; 95 % CI: 0.01, 0.31; P = 0.036) were associated with higher MIP-1ß levels. Conclusions: During acute HCV infection, high ALT and HCV RNA levels were associated with increased IP-10 levels, while high HCV RNA levels were also associated with increased MIP-1ß levels. These data suggest that IP-10 and MIP-1ß may have a role in HCV immuno-pathogenesis starting early in acute HCV infection. [ABSTRACT FROM AUTHOR]

Modeling studies suggest that modest increases in hepatitis C virus (HCV) treatment could lead to substantial reductions in HCV prevalence among people who inject drugs. This article focuses on issues to consider for the feasibility of HCV treatment as prevention.The demonstration that antiretroviral treatment is effective for the prevention of human immunodeficiency virus (HIV) transmission has important implications for HCV prevention. HCV therapeutic development is advancing rapidly, with effective, simplified regimens available in the near future. In contrast to HIV, HCV treatment is both curative and circumscribed in duration—2 features that hold great promise for the potential effectiveness of HCV treatment as prevention, particularly among PWID. Mathematical modeling studies have suggested that modest increases in HCV treatment uptake could lead to substantial reductions in HCV prevalence. This Viewpoint focuses on issues that are important to consider when discussing the feasibility and future requirements of HCV treatment as prevention among PWID. This includes a need to address low rates of HCV screening and treatment, a limited HCV treatment infrastructure, the cost of therapy, and the balance of health priorities at the population and individual levels. [ABSTRACT FROM AUTHOR]

Population-level uptake of direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) infection, including retreatment, can be estimated through administrative pharmaceutical dispensation data. However, the reasons for retreatment are not captured in these data. We developed a machine learning model to classify retreatments as reinfection or treatment failure at a national level. Retreatment data from the REACH-C cohort (n = 10,843 treated with DAAs; n = 320 retreatments with known reason), were used to train a random forest model. Nested cross validation was undertaken to assess model performance and to optimise hyperparameters. The model was applied to data on DAA retreatment dispensed during 2016-2021 in Australia, to identify the reason for retreatment (treatment failure or reinfection). Average predictive accuracy, precision, sensitivity, specificity and F 1 -score for the model were 96.3%, 96.5%, 96.3%, 96.3% and 96.3%, respectively. Nationally, 95,272 individuals initiated DAAs, with treatment uptake declining from 32,454 in 2016 to 6,566 in 2021. Of those treated, 6,980 (7%) were retreated. Our model classified 51.8% (95% CI 46.7–53.6%; n = 3,614) of cases as reinfection and 48.2% (95% CI 46.4–53.3%; n = 3,366) as treatment failure. Retreatment for reinfection increased steadily over the study period from 14 in 2016 to 1,092 in 2020, stabilising in 2021. Retreatment for treatment failure increased from 73 in 2016 to 1,077 in 2019, then declined to 515 in 2021. Among individuals retreated for treatment failure, 50% had discontinued initial treatment. We used a novel methodology with high classification accuracy to evaluate DAA retreatment patterns at a national level. Increases in retreatment uptake for treatment failure corresponded to the availability of pangenotypic and salvage regimens. Increasing retreatment uptake for reinfection likely reflects increasing reinfection incidence. This study used machine learning methodologies to analyse national administrative data and characterise trends in HCV retreatment due to reinfection and treatment failure. Retreatment for reinfection increased over time, reflecting increasing numbers of people at risk for reinfection following HCV cure. Increased retreatment for treatment failure corresponded to the availability of pangenotypic and salvage DAA regimens. The findings of this study can be used by public health agencies and policy makers to guide and assess HCV elimination strategies, while the novel methodology for monitoring trends in HCV retreatment has the potential to be used in other settings, and health conditions. [Display omitted] • Seven percent of people treated for HCV in Australia were retreated. • Machine learning was used to classify retreatments based on national administrative data. • Overall, 52% of retreatment was for reinfection and 48% was for treatment failure. • Retreatment for reinfection increased over time, reflecting increasing numbers of people at-risk for reinfection following cure. • Retreatment for treatment failure increased when salvage DAAs became available. [ABSTRACT FROM AUTHOR]

Background: A barrier to hepatitis C virus (HCV) treatment among people who inject drugs (PWID) has been a concern that interferon-based HCV treatment may increase injecting risk behaviours. This study evaluated recent (past month) injecting risk behaviours during follow-up among PWID that did and did not receive HCV treatment.Methods: The Australian Trial in Acute Hepatitis C (ATAHC) was a prospective study of natural history and treatment of recent HCV infection. Analyses were performed using generalized estimating equations.Results: Among 124 participants with a history of injecting drug use (median age 32 years), 69% were male, and 68% were treated for HCV infection. HCV treatment was not associated with an increase in recent injecting drug use (adjusted odds ratio (aOR) 1.06, 95% CI 0.93, 1.21) or recent used needle and syringe borrowing during follow-up (aOR 0.99, 95% CI 0.89, 1.08). HCV treatment was associated with a decrease in recent ancillary injecting equipment sharing during follow-up (aOR 0.85, 95% CI 0.74, 0.99). Further, among treated participants who remained in follow-up (n=24), ancillary injecting equipment sharing significantly decreased from 54% at enrolment to 17% during follow-up (P=0.012).Conclusions: HCV treatment was not associated with drug use or used needle and syringe borrowing during follow-up, but was associated with decreased ancillary injecting equipment sharing during follow-up. Programs to enhance HCV assessment and treatment among PWID should be expanded, given that HCV treatment does not lead to increases in injecting risk behaviours and has previously been demonstrated to be safe and effective among PWID. [ABSTRACT FROM AUTHOR]