Hepatitis C

The hepatitis C virus (HCV) genome was isolated during the late 1980s using molecular cloning techniques. It is recognized as the cause of most cases of percutaneously transmitted non-A, non-B hepatitis. Prevalence of antibodies to HCV(anti-HCV) in the general Australian population is 0.3%. However, among regular intravenous drug users the prevalence exceeds 90%. The predominant risk factors for HCV are intravenous drug use, tattoos, exposure to blood products, occupational risk and ethnicity. In contrast to hepatitis B, sexual spread and vertical transmission of HCV from mother to neonate are relatively uncommon. The risk of acquiring HCV from a single HCV-contaminated needlestick accident is about 5%. Most cases of acute HCV infection are asymptomatic, but 50 to 80% progress to chronic disease. The percentage of those with chronic HCV progressing to cirrhosis is not accurately known, but is probably 20%. Treatment strategies for HCV, utilizing recombinant interferons, are proving useful in patients with mild to moderate liver disease, but fare less well in patients with cirrhosis. Currently, there is no vaccine for hepatitis C, so pre-exposure prophylaxis is not possible. Equally, no post-exposure intervention, for example with gamma globulin, has been shown to be beneficial, though there may be a role for early interferon therapy.