Grant: Operating Grant - PA: Hepatitis C - Psycho-social/behavioural/epidemiological

In Canada, hepatitis C virus (HCV) infection is a major public health problem associated with considerable morbidity, mortality and health-related costs. In 2007, 243,000 Canadians were infected. Among infected individuals, one in four will develop cirrhosis and one in eight will die from HCV-related causes. Injection drug users (IDUs) represent the core of the HCV epidemic in Canada, with the majority of new (83%) and existing (58%) infections occurring in this group. In Canada, although research has identified characteristics associated with new cases of infection, little is known about transmission events occurring from pools of infected to uninfected individuals. Further, given ongoing risk behaviours for HCV transmission, it is likely that many IDUs harbour multiple infections. We have assembled a multidisciplinary team of international investigators with expertise across disciplines in the fields of HCV and HIV. The overall goal of this project is to evaluate HCV transmission dynamics among IDUs. First, we are interested in how HCV is transmitted from older to younger IDUs and whether public health initiatives have led to a reduction in transmission. Second, we are interested in understanding how frequently reinfection and mixed infections with HCV occur and what characteristics are associated with reinfection/mixed infections. We plan to conduct this study within well-established cohorts of IDUs in Vancouver, the Vancouver Injecting Drug Users Study (VIDUS) and the At-risk Youth Study (ARYS). Using previously stored blood samples from these studies from 1996 to 2010, we plan to identify participants who developed HCV infection, sequence their virus and investigate HCV transmission networks. We will also use novel technologies to detect mixed HCV infections. Understanding HCV transmission among injection drug users will better guide the development of public health and biomedical strategies for HCV prevention.