Comparative immunogenicity of a genetically derived and a plasma pooled hepatitis B vaccine in normal adult volunteers.

Objective: This study compares the seroconversion rate after vaccination with genetically derived and plasma pooled vaccine in normal healthy adult volunteers.

Population And Methods: Forty volunteers of either sex were randomly divided into two groups comprising equal numbers of subjects. The mean (+/- SD) age and weight of the subjects in group A were 27.52 +/- 3.48 years and 65.60 +/- 8.06kg, respectively, while the mean (+/- SD) values for the individuals in group B were 30.75 +/- 3.78 years and 68.55 +/- 6.59kg. Recombinant and plasma pooled vaccines were administered as single 20 microg and 3 microg intramuscular injections to the respective groups of volunteers on days 1, 30, and 180. An automated system (AxSYM, based on microparticle enzyme immunoassay) was used to measure the seroconversion rate in serum harvested from an 8 mL blood sample collected within 1 month of the third dose (i.e., on day 210), from each volunteer.

Results: Both of the vaccines were well tolerated by all individuals and no adverse reaction was reported or observed during the study. The subject seroconversion rate corrected with reference to the cut-off rate after vaccination with DNA-derived vaccine was significantly greater (p < 0.05) than that observed after the administration of plasma pooled-derived vaccine (51.64 +/- 17.00 versus 22.96 +/- 12.04).

Conclusion: The vaccine response, as indicated by the seroconversion rate (concentration of anti-HBs in mIU/mL) in the group vaccinated with genetically derived vaccine was observed to be better (p < 0.01) when matched with the International Antibody Standard.