A new pre-S containing recombinant hepatitis B vaccine and its effect on non-responders: a preliminary observation

Nine healthy subjects who had no detectable antibody response when initially vaccinated with hepatitis B vaccine (plasma derived and/or yeast derived) were revaccinated with three 20 micrograms doses of a new recombinant hepatitis B (HB) vaccine (SCI-B-VAC) derived from Chinese hamster ovary (CHO) cells and consisting of both the major S protein and the minor pre-S (S1 and S2) proteins of the viral coat. Seroconversion was successful in 78% of these non-responders after the second dose and just before the third vaccination. The geometric mean titres of the antiHBs were 587 iu/l one month after the course of vaccination. This study, though preliminary, indicated that pre-S containing CHO vaccine is effective in inducing antibody response in S-vaccine non-responders and also suggested that the added pre-S region in HBV vaccine helps antiHBs production. Frequency of HLA B46 and B15 were higher in non-responders compared to normal subjects (P = 0.04) supporting the possibility that genetic factors may modulate the immune response to HB vaccination.