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ID: HR23-687
Presenting author: Lisa Maher

Presenting author biography:

Kirby Institute Program Head, Professor in the Faculty of Medicine, UNSW Sydney, NHMRC Senior Research Fellow, and Honorary Senior Principal Research Fellow, Burnet Institute. Professor Maher has three decades of international experience in research, program evaluation and service delivery with key populations, focussing on HIV, viral hepatitis and STIs.

Incidence of primary hepatitis C infection among people who inject drugs in Australia: Progress towards elimination

Lisa Maher, Jenny Iversen, Handan Wand, Hamish McManus, Gregory Dore
Introduction: The 2016 Global Health Sector Strategy (GHSS) on viral hepatitis aims to reduce new hepatitis C virus (HCV) infections by 80% by 2030, including a 30% reduction by 2020. This study aimed to estimate primary HCV incident infection among a national sample of people who inject drugs (PWID) before and after the introduction of unrestricted access to HCV direct acting antiviral (DAA) therapy via Australia’s Pharmaceutical Benefits Scheme in 2016.
Methods: Two retrospective cohorts of HCV antibody negative respondents were created from serial cross-sectional surveys using a simple deterministic method that linked partial identifiers among repeat respondents. Both cohorts comprised six years, corresponding to pre- (2010-2015) and post- (2016-2021) DAA time-periods. The primary outcome was HCV seroconversion, defined as a negative HCV antibody test result followed by a positive HCV antibody result. Time to primary incident HCV infection was estimated using the person years (PY) method.
Results: Of 757 people who inject drugs attending needle syringe programs (376 pre-DAA, 381 post-DAA), just under two thirds were male, Australian-born and identified as heterosexual. A total 97/376 (2010-2015) and 41/381 (2016-2021) HCV seroconversions were identified. Primary HCV incidence more than halved, from 13.6/100PY (95% confidence intervals [CI] 11.2,16.6) in 2010-2015 to 5.4/100PY (95% CI 3.9,7.3) in 2016-2021. The decline was independent of observed differences in demographic and drug use characteristics over the two time-periods (adjusted hazard ratio 0.47, 95% CI 0.31-0.69, p<0.001).
Conclusions: Given people who inject drugs are the predominant population at risk of HCV infection in Australia, findings add to the evidence that Australia met the 2020 GHSS sub-target of a 30% decline in new infections. However, to achieve the GHSS 2030 targets Australia needs to maintain this momentum by intensifying efforts to ensure equitable access to prevention, diagnosis and treatment.