Infection with the RNA-containing hepatitis C virus, which was isolated little more than 10 years ago, causes damage to the liver resulting in cirrhosis, liver failure and cancer of the liver. In the majority of individuals, hepatitis C infection progresses slowly over many years and approximately 85% of those who contract the disease remain chronically infected, with the virus replicating throughout their lifetime. Lifelong measures are, therefore, required to limit the spread of infection to others. The importance of the disease is clear from the fact that 170 million people are estimated to be chronically infected worldwide. In the USA, where liver failure from chronic hepatitis C infection is one of the most common reasons for liver transplants, some 4 million people are infected by the virus. Hepatitis C is probably also the most common cause of primary liver cancer in the developed world.

There is no doubt that important advances have been made in recent years. As detailed in this book, the development and deployment of assays that specifically detect anti-HCV antibodies and HCV RNA in infected patients have reduced the risk of acquiring HCV from contaminated blood to almost zero. However, there is currently no cure for liver disease caused by hepatitis C, and interferon therapy is of limited efficacy and has significant side-effects.