In the U.S., hepatitis C virus (HCV) infection is the most common cause of chronic hepatitis, and the complications of hepatitis C virus cirrhosis are the most common reasons for liver transplantation.
Hepatitis C virus is one of several viruses (A, B, C, D, and E) that can cause hepatitis (inflammation of the liver). hepatitis C virus is distinct from these other viruses.
One of the major problems with hepatitis C virus is that 85% of individuals who are initially (acutely) infected with hepatitis C virus will become chronically (long duration) infected. About one third of individuals chronically infected with hepatitis C virus will progress to cirrhosis.
Hepatitis C virus is spread (transmitted) through the blood. Intravenous drug abuse is the most common mode of transmission, while the risk of acquiring hepatitis C virus through sexual contact is quite low.
Generally, patients do not develop symptoms until they have progressed to advanced cirrhosis. Some individuals, however, may have fatigue and other non-specific symptoms in the absence of cirrhosis. A minority of hepatitis C virus patients may have symptoms coming from involved organs outside of the liver.
Hepatitis C is diagnosed by anti-hepatitis C virus antibody tests, which diagnosis is then confirmed by nucleic acid based tests for the virus itself. The amount of the virus in the blood (viral load) does not correlate with the severity of the disease.
A liver biopsy is used to assess the amount of liver damage (liver cell injury and scarring), which may be important in determining the outcome (prognosis) and in planning treatment.
Considerable progress has been made in the treatment of hepatitis C virus. For patients infected with genotype 2 or 3, successful treatment with combined interferon (conventional or pegylated) and ribavirin can be achieved in up to 80% of patients.
Treatment for patients infected with genotype 1 hepatitis C virus, for whom the success rate with combined pegylated interferon and ribavirin is just under 50%, remains a challenge.
Treatment is recommended for patients with detectable hepatitis C virus RNA who have persistently elevated liver tests and evidence of scarring and at least moderate inflammation on their liver biopsy, but without outward signs of liver failure.
Treatment results in improvement in the inflammation and scarring of the liver in most sustained responders and also occasionally (and to a much lesser extent) in relapsers and non-responders.
Clinical trials are underway to evaluate combinations of various antiviral agents and pegylated interferon in the treatment of hepatitis C.