Assessing and improving the Hepatitis C virus cascade of care for marginalised populations

Abstract

Much emphasis has been placed on addressing the gap in diagnosis and treatment of hepatitis C virus (HCV) among people who inject drugs (PWID) in order to achieve HCV elimination. In this thesis we describe, identify and address challenges to enhancing retention to the HCV cascade of care in two marginalised populations. These findings informed a decision tree and Markov state transition model to assess the cost-effectiveness of scaling-up screening and treatment, designed to reflect the process for each setting. First, we describe the HCV cascade of care for PWID attending a methadone clinic in Dar-es-Salaam, Tanzania, indicating almost one-third had HCV exposure and a significant burden of liver disease (17% moderate fibrosis or cirrhosis). As reliable access to HCV nucleic acid testing was identified as a major obstacle, novel methods of HCV viraemia confirmation were validated in this setting. Dry blood spot (DBS) HCV core antigen was limited by suboptimal sensitivity (76%), while Xpert® HCV fingerstick viral load had an excellent performance, with the need for repeat sampling being the main drawback. Incarcerated individuals in a London remand prison were the other focus of this thesis. We found that the existing DBS-based cascade of care was time-sensitive and introducing a rapid point-of-care-based screening an fast-track treatment intervention doubled screening uptake and resulted in a four-fold increase in treatment initiation. Improved HCV screening and treatment is likely to be cost-effective in both settings. The cost of harm reduction (HR) has the largest influence on the outcome among PWID in Dar-es-Salaam, while resource-determined universal or targeted strategies may both be useful in remand prison settings, adherence to all aspects of the cascade of care is fundamental. Overall, a simplified model of care employing innovative technology and integration of existing resources and services represents a strong formula to overcome the existing challenges to scaling-up HCV care among marginalised communities.