Differential Immunogenicity of A Recombinant Hepatitis B Vaccine in Iranian Neonates:Influence of Ethnicity and Environmental Factors

Objective: To compare immunogenicity of a recombinant hepatitis B (HB) vaccine in two groups of neonates born in two cities of Iran with different geographic and ethnic backgrounds. Materials and Methods: Ten micrograms of a recombinant HB vaccine was administered under field condition to Iranian healthy neonates at 0, 1.5 and 9 months intervals. The subjects consisted of two groups of 290 and 231 neonates selected from two cities located at north-west (Urmia) and south-east (Kerman) of Iran, respectively. The level of anti-HBs antibody was quantitated in serum 2-4 weeks after administration of the last vaccine dose, by sandwich ELISA. Results: A higher seroprotection rate (anti-HBs> 10 IU/L) (98.3% vs. 96.1%) and significantly increased serum anti- HBs antibody titer (11869 vs. 6104 IU/L) (P<0.001) were induced in vaccinated neonates from Urmia city, compared to those born in Kerman. Conclusion: These findings suggest contribution of ethnic and/or environmental factors in the antibody response to recombinant HB vaccine in human