The challenge of developing a vaccine against hepatitis C virus

It is apparent that the development of an HCV vaccine poses a great challenge to the scientific community. Some difficulties are inherent to the virus, such as its high genetic heterogeneity and the ability to establish persistent infections, perhaps by escaping the host immune responses. Other limitations are technical, such as the lack of a cell culture system or a small animal model for HCV. Several studies have demonstrated that neutralizing antibodies to HCV exist, but that they appear to be isolate- or strain-specific and thus, a vaccine capable of generating sterilizing immunity is a challenge. Studies performed in humans and chimpanzees suggest that resolution of HCV infection is associated with a strong cellular immune response. Since hepatitis C virus causes the most serious liver damage after an extremely protracted course, a vaccine that generates immune responses capable of converting an evolving persistent infection into a self-limiting infection represents a reasonable goal and would have major impact on the disease caused by HCV infection.