Hepatitis C virus (HCV) infections remain a major public health problem among people who inject drugs. Until now, however, studies of HCV infection in this group have been limited by the small size of study populations. To address this limitation and help answer important questions about the HCV virus and about outcomes in drug users infected with it, the International Collaboration of Incident HIV and Hepatitis C Injecting Cohorts (InC3) Study is pooling biological and behavioral data from nine prospective cohorts of injecting drug users in the United States, Australia, Canada, and the Netherlands. Findings from the study could give us a better understanding of factors associated with spontaneous clearance of HCV infection from an infected person; formerly, the small numbers of reported cases and the heterogeneity of study designs and methods have impeded such knowledge. Early work from InC3, which began in 2009, has already provided important information about whether previously being infected with HCV reduces a person’s chance of reinfection or the likelihood of spontaneously clearing a subsequent infection. Current data suggest that women with certain genotypes may clear the virus spontaneously without treatment, and that reinfection with HCV probably occurs more frequently than believed before. This and other information gained from the InC3 study will be valuable for developing new vaccines and for guiding treatment of people infected with HCV.
For a copy of the study abstract, go to: http://ije.oxfordjournals.org/content/early/2012/11/30/ije.dys167.abstract.