1 Population Health Sciences, University of Bristol, Bristol, UK.
2 National Institute of Health Research (NIHR) Health Protection Research Unit (HPRU) in Evaluation of Interventions, Bristol, UK.
3 National Drug and Alcohol Research Centre, UNSW Sydney, Sydney, NSW, Australia.
4 Centre for Youth Substance Abuse Research, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia.
5 Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, United States.
6 The Kirby Institute, UNSW Sydney, Sydney, NSW, Australia.
7 Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA, USA.
8 National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK.
The World Health Organization (WHO) recently produced guidelines advising a treat-all policy for HCV to encourage widespread treatment scale-up for achieving HCV elimination. We modelled the prevention impact achieved (HCV infections averted [IA]) from initiating this policy compared with treating different subgroups at country, regional and global levels. We assessed what country-level factors affect impact. A dynamic, deterministic HCV transmission model was calibrated to data from global systematic reviews and UN data sets to simulate country-level HCV epidemics with ongoing levels of treatment. For each country, the model projected the prevention impact (in HCV IA per treatment undertaken) of initiating four treatment strategies; either selected randomly (treat-all) or targeted among people who inject drugs (PWID), people aged ≥35, or those with cirrhosis. The IA was assessed over 20 years. Linear regression was used to identify associations between IA per treatment and demographic factors. Eighty-eight countries (85% of the global population) were modelled. Globally, the model estimated 0.35 (95% credibility interval [95%CrI]: 0.16-0.61) IA over 20 years for every randomly allocated treatment, 0.30 (95%CrI: 0.12-0.53) from treating those aged ≥35 and 0.28 (95%CrI: 0.12-0.49) for those with cirrhosis. Globally, treating PWID achieved 1.27 (95%CrI: 0.68-2.04) IA per treatment. The IA per randomly allocated treatment was positively associated with a country's population growth rate and negatively associated with higher HCV prevalence among PWID. In conclusion, appreciable prevention benefits could be achieved from WHO's treat-all strategy, although greater benefits per treatment can be achieved through targeting PWID. Higher impact will be achieved in countries with high population growth.