Estimating the Consensus hepatitis C Cascade of Care among people who inject drugs in Australia: Pre and post availability of direct acting antiviral therapy

Background Monitoring the hepatitis C virus (HCV) cascade of care (CoC) among people who inject drugs (PWID) is an essential component of the response to World Health Organisation's (WHO) hepatitis elimination goals. This study aimed to estimate the Consensus hepatitis C CoC among PWID using data collected in Australia prior to and after the introduction of unrestricted direct-acting antiviral (DAA) therapy in March 2016. Methods The Australian Needle Syringe Program Survey is a cross-sectional bio-behavioural surveillance system that recruits >2000 PWID annually. Using data from 2015 and 2019, HCV antibody and ribonucleic acid (RNA) test results from dried blood spots were combined with self-reported data on HCV diagnostic testing and treatment to project HCV Consensus CoC indicators at a population-level among Australian PWID. Results Among an estimated 75,000 people who inject drugs on a regular basis in Australia, the number with active HCV infection declined from 32,619 (44%) in October 2015 to 12,679 (17%) in October 2019. The majority (78% in 2015 and 2019) of PWID reported HCV diagnosis, while the proportion of those diagnosed who were treated increased from 3% in 2015 to 47% in 2019. Among those treated, the proportion who were HCV RNA negative and assumed to have been successfully treated (cured), increased from 27% in 2015 to 88% in 2019. Conclusion This study demonstrates remarkable HCV CoC progress among PWID in Australia following availability of DAA therapy. There was a substantial increase in the proportion of HCV diagnosed PWID who initiated treatment and were cured, while the number of PWID with active HCV infection more than halved over a 3.5 year period. Estimates of the Consensus hepatitis C CoC among PWID is required to monitor progress toward WHO HCV elimination goals.