Many recent and significant advances in the field of chronic viral hepatitis, including therapy, suggest that an update on chronic hepatitis is timely.Chronic hepatitis B virus infection remains a significant worldwide cause of liver cirrhosis and hepatocellular carcinoma, despite the wide availability of a long established and eVective vaccine. Transmission occurs via perinatal, sexual, and parenteral routes (particularly intravenous drug abuse and although blood products still carry a risk, this is now extremely low in Western countries). Only a minority of infected adult cases develop chronic hepatitis but in children under 1 year, 90% develop chronic hepatitis. The clinical spectrum of chronic liver injury ranges from mild inflammation to end stage liver cirrhosis. Interferon alfa has been the mainstay of treatment for patients with active disease but nucleoside analogues (lamivudine and adefovir) are now available with similar eYcacy. Patients with end stage liver disease and hepatocellular carcinoma can be oVered transplantation but infection in the graft is commonplace. The combination of hepatitis B immunoglobulin and newer antiviral drugs reduce the incidence and severity of graft infection significantly.The hepatitis C virus epidemic of the latter half of the 20th century now aVects more than 1% of populations worldwide. This RNA virus is spread parenterally and is becoming the leading indication for liver transplantation. The majority of patients develop chronic hepatitis, which may be progressive, evolving to significant liver disease (cirrhosis or hepatocellular carcinoma) in about 20% cases after decades. Treatment with the combination of interferon alfa and ribavirin is successful in up to 40% cases. Liver transplantation is a therapeutic option for some but graft infection is universal and often complicated by progressive liver fibrosis. A vaccine remains a remote prospect so that prevention is crucial.Hepatitis D virus infection occurs on a background of hepatitis B virus infection and can also cause liver damage. The response to antiviral therapy is poor.The newer "hepatitis" viruses G and TT do not cause significant liver injury. (Postgrad Med J 2001;77:498-505) Keywords: hepatitis A number of viruses are known to cause chronic hepatitis. These include hepatitis B and D viruses identified in the 1960s and 1970s respectively and hepatitis C virus isolated in 1989. More recently, newer "hepatitis" viruses such as hepatitis G and TTV have been described, although their role in chronic hepatitis is in doubt. Hepatitis A virus does not cause chronic infection.
Hepatitis B virusEPIDEMIOLOGY Chronic hepatitis B virus (HBV) infection accounts for 5%-10% of cases of chronic liver disease and cirrhosis in the United States.1 It aVects 350 million people worldwide. The major modes of transmission of HBV are perinatal, sexual (via semen and vaginal secretions), via blood products, and via contaminated needles in intravenous drug addicts. A recent US study found that the prevalence of HBV infect...