In England, 160,000 individuals were estimated to be chronically infected with hepatitis C virus (HCV) in 2005 and the burden of severe HCV-related liver disease has increased steadily for the past 15 years. Direct-acting antiviral treatments can clear infection in most patients, motivating HCV elimination targets. However, the current burden of HCV is unknown and new methods are required to monitor progress. We employ a Bayesian back-calculation approach, combining data on severe HCV-related liver disease and disease progression, to reconstruct historical HCV incidence and estimate current prevalence in England. We explicitly model infections occurring in people who inject drugs, the key risk group, allowing information on the size of this population and surveillance data on HCV prevalence to inform recent incidence. We estimate 143,000 chronic infections in 2015 (95% credible interval 123,000-161,000), with 34% and 54% in those with recent and past injecting drug use respectively. Following the planned scale-up of new treatments, chronic infections are predicted to fall to 113,400 (94,900-132,400) by the end of 2018 and to 89,500 (71,300-108,600) by the end of 2020. Numbers developing severe HCV-related liver disease are predicted to fall by at least 24% from 2015 to 2020. We describe a coherent framework to monitor progress using routinely-collected data, which can be extended to incorporate additional data sources. Planned treatment scale-up is likely to achieve 2020 WHO targets for HCV morbidity, but substantial efforts will be required to ensure that HCV testing and patient engagement are sufficiently high.
Bibliographical note© 2019 The Authors. Journal of Viral Hepatitis Published by John Wiley & Sons.
- back calculation
- direct-acting antiviral treatment
- disease burden
- people who inject drugs
- surveillance data