VIRAL-HEPATITIS

In clinical trials, live attenuated and formol-inactive vaccines against hepatitis A have proved immunogenic. Problems in delivering hepatitis B vaccine to underdeveloped countries are discussed. The polymerase chain reaction can be used to show hepatitis B virus DNA in liver and serum even in hepatitis B e antigen-negative patients. Hepatitis B viral mutants have been associated with fulminant disease. Interferon therapy is successful in 30% to 50% of those treated. Late liver biopsy specimens show resolution of inflammatory change. New second-generation tests for anti-hepatitis C virus antigen confirm positivity and give fewer false results. Hepatitis C virus RNA can be detected by polymerase chain reaction. This finding confirms infectivity and can be used to follow treatment. Mutants of hepatitis C virus are being described; their clinical significance is uncertain. There are approximately 500 million carriers of hepatitis C virus worldwide. The majority have no obvious risk factors and their mode of infection remains unclear. Interferon therapy gives long-term benefit in about 25% of chronic hepatitis C virus patients. Selection of patients to treat and dose and duration of therapy remain undecided. Ribavirin is giving interesting results.