Immunogenicity of a new, low-cost recombinant hepatitis B vaccine derived from Hansenula polymorpha in adults

BackgroundHepatitis B virus (HBV) infection is highly prevalent world over, especially in developing countries. A new recombinant hepatitis B virus (GeneVac-B; Serum Institute of India Ltd.) vaccine is developed using Hansenula polymorpha yeast. We decided to assess the immunogenicity, and reactogenicity of this vaccine in a large adult population.Material and methodsSeven hundred eighty-eight adults subjects (age: 19–57 years, male:female ratio 35:1) received three 20 μg doses of a H. polymorpha-derived recombinant hepatitis B vaccine in months 0, 1, and 6. All the eligible subjects had negative baseline serum HBs Ag, and anti-HBs. The anti-HBs titer was obtained 1 month after the last dose of vaccine and was considered seroconverted if more than 1 mIU/ml, and seroprotective if more than 10 mIU/ml.ResultsThe seroprotection rate was 96% and seroconversion rate was 97%. Seroconversion and seroprotection rates declined with increasing age. The minimum geometric mean titre of anti HBs was 443 mIU/ml (95% CI 407–482). Seroprotection was 96% in age group <40 years, while the same was 91% in >40 years group (Odd's ratio—2.9100, Z value—2.6183, highly significant). No other factor like smoking, tobacco-chewing, alcohol consumption, chronic diseases, and obesity, affected the immune response. No significant adverse reactions were reported in any of the subjects.ConclusionsThree standard doses of the H. polymorpha-derived recombinant HBV vaccine are highly immunogenic and safe in a predominantly male adult population. Young adults respond better with this vaccine. Because of its low cost, the vaccine may be a good choice in prevention of hepatitis B infection.