Evaluation of immunogenicity and safety of Genevac B: a new recombinant hepatitis B vaccine in comparison with Engerix B and Shanvac B in healthy adults.

Purpose: Genevac B, a new indigenous recombinant hepatitis B vaccine was evaluated for its immunogenicity and safety in comparison with Engerix B (Smithkline Beecham Biologicals, Belgium) and Shanvac B (Shantha Biotechnics, India) in healthy adult volunteers.

Methods: While 240 study subjects were included in the Genevac B group, 80 each were the subjects for Engerix B and Shanvac B. A three dose regimen of 0,1,2 months was adopted with 20 gm dosage uniformly in all the three groups. Vaccinees were assessed during prevaccination, followup and post vaccination periods for clinical, haematological, biochemical and immunological parameters for safety and immunogenicity.

Results: Successful follow-up in all parameters for four months could be achieved in 92.5% (222/240) for Genevac B study subjects and the same was 85% (68/80) and 80% (64/80) for Engerix B and Shanvac B respectively. While 100% seroconversion was observed in all the three groups, the rate of seroprotectivity was 99.5% by Genevac B, 98.5% by Engerix B and 98.4% for Shanvac B. However the difference was not statistically significant (p>0.05). The GMT values of anti HBs after one month of completion of the vaccination were 735.50, 718.23 and 662.20 mIU/mL respectively. No systemic reaction was either seen or reported by the volunteers during the vaccination process of Genevac B and other two vaccines. Clinical, haematological and biochemical safety parameters remained within normal limits throughout the study period.

Conclusion: The study confirms that Genevac B, the new recombinant Hepatitis B vaccine has the acceptable international standards of safety and immunogenicity.