Viral hepatitis: implications to pediatric practice.

A major frontier is the development of effective therapy for patients with chronic type B hepatitis, which currently remains refractory to all known antiviral agents and is associated with severe long-term consequences. Future research should focus on the relationship of HBV to hepatocellular carcinogenesis. This might answer the question as to when integration of viral DNA into the host cell occurs and whether this is an irreversible step in the progression toward hepatocellular carcinoma. The exciting work regarding vaccines against human hepatitis will continue in view of the worldwide impact of elimination of these viruses. Chemically synthesized vaccines may be safer, cheaper, and more effective, and also produce more persistent protective immunity. This technology requires determination of immunogenic protein molecules, identification and in vivo synthesis of the amino acid sequences important for cellular recognition, and the application of recombinant DNA technology to clone and propagate the critical antigenic determinants by incorporation into other hosts such as vaccinia. The potential of newer forms of hepatitis B vaccine has been demonstrated by the study of Scolnick et al., in which HBsAg, produced by a recombinant strain of yeast, was given to 37 healthy low-risk volunteers as a means of vaccination. The dose and schedule were the same as that used for the serum HBsAg-derived vaccine. The results were encouraging in that an 80%-100% anti-HBs positivity was documented at three months in these individuals. These experiences also suggest that a similar sequence of events, namely definition, elucidation of the molecular biology, and development of immunologic prevention of non-A, non-B viruses is at hand.