Type B hepatitis: progression to chronic hepatitis.

The ability to test for HBV associated antigens has provided evidence that viral hepatitis is a common cause of chronic liver disease world-wide. Fewer than 10% of cases of acute icteric HBV become chronic, but chronicity is more common after anicteric infections. The prognosis for chronic persistent hepatitis B is usually good whereas many cases of chronic active hepatitis B will progress to cirrhosis although the time scale may be long. Factors determing the severity of the liver disease and the progression to chronicity are unclear, but the immune response of the host to the infection seems to play a major role.