Grant: CIHR Fellowship

Over 150 million people worldwide are infected with hepatitis C virus (HCV) including more than 240,000 Canadians. HCV causes liver damage in infected individuals. Over time, this damage can lead to life-threatening liver cancer. Until recently, no acceptable therapy for HCV has existed. In the past five years, new drugs have been developed that can cure most patients' HCV infection in a matter of weeks. Despite this breakthrough, HCV is far from being eradicated. First, the high cost of treatment (up to $100,000 per person) limits its widespread use. More importantly, the incredible genetic diversity of HCV makes it very difficult to treat. HCV is not a single virus, but rather a collection of several related strains. Many of the current drugs only work on one type of HCV called genotype 1 (GT1), the most common strain in Canada. Patients' HCV genotype must therefore be accurately determined before starting therapy. For example, using a drug that only works for GT1 to treat a patient with genotype 3 HCV would not be effective and would expose them unnecessarily to potential side effects. It would also be a waste of our limited healthcare dollars. Furthermore, some patients can be infected with more than one HCV strain at the same time. This multiple-genotype, or "mixed" HCV infection is most common in persons who inject drugs. Treating these patients using the present generation of drugs would eliminate only some of the virus, leaving the rest to multiply. Unfortunately, the current tests used to determine HCV genotype cannot reliably detect mixed infection. This application proposes to develop a new genetic test that detects multiple-genotype HCV infection. This test would be used to determine which patients can be treated with the current HCV drugs, and which may need to wait for future treatment options. It will also be used to examine how much of the Vancouver injection drug using population is infected with multiple HCV strains and the reasons why this occurs.