Hepatitis C This is caused by an RNA flavivirus. Acute symptomatic infection with hepatitis C is rare. Most individuals are unaware of when they became infected and are identified only when they develop chronic liver disease. Eighty per cent of individuals exposed to the virus become chronically infected and late spontaneous viral clearance is rare. There is no active or passive protection against hepatitis C virus (HCV). Hepatitis C infection is usually identified in asymptomatic individuals screened because they have risk factors for infection, such as previous injecting drug use , or have incidentally been found to have abnormal liver blood tests. Although most people remain asymptomatic until progression to cirrhosis occurs, fatigue can complicate chronic infection and is unrelated to the degree of liver damage. Hepatitis C is the most common cause of what used to be known as 'non-A, non-B hepatitis'. If hepatitis C infection is left untreated, progression from chronic hepatitis to cirrhosis occurs over 20-40 years. Risk factors for progression include male gender, immunosuppression (such as co-infection with HIV), prothrombotic states and heavy alcohol misuse. Not everyone with hepatitis C infection will necessarily develop cirrhosis but approximately 20% do so within 20 years. Once cirrhosis has developed, the 5- and 10-year survival rates are 95% and 81%, respectively. One-quaer of people with cirrhosis will develop complications within 10 years and, once complications such as ascites develop, the 5-year survival is around 50%. Once cirrhosis is present, 2-5% per year will develop primary hepatocellular carcinoma. Ref Davidson edition23rd pg877