Abstract
Hepatitis C virus (HCV) accounts for the majority of cases of transfusion acquired hepatitis and hepatitis transmitted by injecting drug use. The patients who do not clear the infection become chronic carriers of HCV and form a reservoir of infection within human populations. Furthermore, these carriers are at serious risk of developing cirrhosis of the liver and hepatocellular carcinoma. The disease is of major concern in developing as well as in developed countries and yet there are no vaccines against HCV, treatment is confined to the use of chemotherapy which is expensive and not always effective. The major obstacle in vaccine development is a limited understanding of the type of immune response that is necessary for viral clearance and the occurrence of various genotypes and quasispecies of HCV. The problems are further compounded by difficulties in growing the virus in vitro and the lack of a suitable and economical animal model.