The role of prison-based interventions for hepatitis C virus (HCV) micro-elimination among people who inject drugs in Montreal, Canada

Background: In Canada, hepatitis C virus (HCV) transmission primarily occurs among people who inject drugs (PWID) and people with experience in the prison system bare a disproportionate disease burden. These overlap-ping groups of individuals have been identified as priority populations for HCV micro-elimination in Canada, which is currently not on track to achieve its elimination targets. Considering the missed opportunities to inter-vene in provincial prisons, this study aims to estimate the population-level impact of prison-based interventions and post-release risk reduction strategies on HCV transmission among PWID in Montreal, a Canadian city with high HCV burden. Methods: A dynamic HCV transmission model among PWID was developed and calibrated to community and prison bio-behavioural surveys in Montreal. Then, the relative impact of prison-based testing and treatment or post-release linkage to care (both 90% testing and 75% treatment coverage), alone or in combination with strategies that reduce the heightened post-release transmission risk by 50%, was estimated from 2018 to 2030, and compared to counterfactual scenarios. Results: Prison-based test-and-treat strategies could lead to the greatest declines in incidence (48%; 95%CrI: 38-57%) over 2018-2030 and prevent the most new first chronic infections (22%; 95%CrI: 16 - 28%) among people never exposed to HCV. Prison testing and post-release linkage to care lead to a slightly lower decrease in incidence and prevented fraction of new chronic infections. Combining test-and-treat with risk reduction measures could further its epidemiological impact, preventing 35% (95%CrI: 29 - 40%) of new first chronic infections. When implemented concomitantly with community-based treatment scale-up, prison-based interventions had synergistic effects, averting a higher fraction of new first chronic infections. Conclusion: Offering HCV testing and treatment in provincial prisons, where incarcerations are frequent and sentences short, could change the course of the HCV epidemic in Montreal. Prison-based interventions with potential integration of post-release risk reduction measures should be considered as an integral part of HCV micro-elimination strategies in this setting.