Needle and syringe sharing among people who have recently injected drugs in Australia: The ETHOS Engage Study.

INTRODUCTION: Understanding needle/syringe sharing is crucial for reducing hepatitis C virus (HCV) infection and reinfection. This study aimed to assess the prevalence and factors associated with needle/syringe sharing among people who inject drugs in Australia, including those previously receiving HCV treatment.

METHODS: The ETHOS Engage study was an observational cohort study which collected self-reported survey data on demographic and drug use information from people who inject drugs attending drug treatment clinics and needle and syringe programs over two waves between May 2018 and June 2021. Logistic regression was used to identify factors associated with needle/syringe sharing.

RESULTS: Overall, 1555/2395 people enrolled in ETHOS Engage (65%) injected drugs in the past month. Among these, 432 (28%) reported needle/syringe sharing in the past month and 276 (18%) reported receptive sharing. Factors associated with receptive sharing included younger age (adjusted odds ratio [aOR] 1.72; 95% confidence interval [CI] 1.28-2.30), recent incarceration (aOR 2.04; 95% CI 1.40-2.94), more frequent injecting (≥daily vs. less than weekly; aOR 2.59; 95% CI 1.75-3.84) and unstable housing (aOR 1.78; 95% CI 1.26-2.52). Among 560 participants with prior HCV treatment, 87 (16%) reported receptive sharing with younger age (aOR 2.42; 95% CI 1.45-4.05) and daily or greater injection frequency (aOR 2.51; 95% CI 1.31-4.83) associated with receptive sharing.

DISCUSSION AND CONCLUSIONS: Needle/syringe sharing was common among this population accessing harm reduction services. This study identifies high-risk populations with needle/syringe sharing. Research is needed to optimise HCV treatment to ensure people with ongoing risk behaviours receive adequate harm reduction following treatment to prevent reinfection.