Theme: Epidemiology & Public Health Research Year: 2024
Background: Developing comprehensive and inclusive care programs to address the needs of PWUD is an absolute prerequisite for the elimination of HCV infection as a public health concern by 2030. A primary challenge associated with such initiatives is the need for effective strategies to mitigate the risk of reinfection after successful therapy. Meta-analyses suggest a reinfection rate of approximately 5 per 100 person-years in this group, but some real-world cohorts report significantly higher rates. We hypothesize that maintaining continuous engagement in care after successful therapy would significantly reduce reinfection rates and maximize the benefits of HCV therapy for PWUD. The purpose of this analysis is to evaluate reinfection rates and their correlates among active PWUD maintained in long-term multidisciplinary care during and after HCV therapy administration.
Method: We provide HCV therapy to PWUD within the context of a program addressing all medical, social, mental health, and addiction-related needs with antiviral medications administered weekly, with daily observed therapy implemented if required to optimize adherence. After a cure has been achieved, participants continue to be integrated in care, with dedicated interventions to minimize behaviours associated with reinfection risk. HCV RNA testing is repeated annually, or more frequently if clinically indicated.
Results: Among 305 individuals who successfully completed HCV treatment between 03/10-08/23 who remained in care and had ongoing reinfection risk, we note: median age of 47 (22-83) years, 29.7% female, 21.2% identifying as indigenous, 52.3% unstably housed, and 93% continuing active intravenous drug use with fentanyl. We documented 11 cases of reinfection, a rate of 1.8 cases per 100 person-years. Of these 11 reinfected patients, 2 were female, 2 identified as indigenous, and all were experiencing unstable housing and ongoing intravenous drug use.
Conclusions: To our knowledge, this is the largest single-center longitudinal evaluation of HCV reinfection rates among active PWUD in a cohort enriched for factors of instability (high rates of fentanyl use, unstable housing) previously associated with higher rates of reinfection. Not only have we documented low rates (< 2/100 person-years), we have identified a factor (unstable housing) which could be the subject of targeted interventions to reduce this rate even further, in addition to other health benefits such interventions would produce. Implementation of programs such as ours will contribute significantly to the goal of eliminating HCV infection as a public health concern by 2030, particularly in this vulnerable population.
Disclosure of Interest Statement:
Dr. Conway has received research grants, honoraria and/or acted as a remunerated advisor for AbbVie, Astra Zeneca, Gilead Sciences, GSK, Indivior Canada, Merck, Moderna, Sanofi Pasteur, Seqirus, and ViiV Healthcare. In particular, AbbVie and Gilead Sciences have funded the community pop-up clinic program in a direct way.