Recent advances in Hepatitis B vaccination

Hepatitis B virus is a microorganism formed in the excess of surface antigen which is devoid of nucleic acid. Surface antigen of HBV was from the beginning the natural candidate for the vaccine which was thus produced by isolation of plasma HBsAg and later substituted by recombinant protein(s). The Extended Program of Immunization was beneficial for the reduction of HBV incidence in the populations of many participating countries. It is further postulated that HCC incidence in the world was also reduced at least in the portion caused by hepatitis B virus. Persistence of anti-HBV immunity was first measured by quantitative anti-HBs assay determined at 1 month post vaccination cycle, and then at different time points, even up to 12-15 years. The frontier of 10 IU/L (mIU/ml) is a mark of sustained immunity. However, cellular immunity studies revealed that this kind of response is very important in the defense against the virus and may last longer than the detectable antibodies. It was shown that ′full′ surface vaccines, i.e. preS+S, may give stronger immunity and are good even for neonates. The next generation vaccines are DNA-based and plant-based HBV vaccines. This last category raises many hopes and with sufficient immunogenicity could ensure the most comfortable route of administration.