ABSTRACT
ABSTRACT Background: The aim of this study was to assess the effectiveness of hepatitis B vaccination and factors associated with vaccine unresponsiveness in healthy children. Methods: A total of 141 healthy children aged between two and five years were included in the study. All of the cases had received 20 μg of recombinant DNA vaccine for hepatitis B (0, 1 and 6 months). Demographic features and factors such as duration of breastfeeding, exposure to HBsAg-positive family members, administration of concomitant vaccines and exposure to smoke were determined. Hepatitis B vaccination serological markers were evaluated. Post-vaccination serologic evaluation was performed one month after the last dose of primary vaccination, one month after the booster dose. Human leukocyte antigens typing was performed in non-responders. Results: Only 87.9% of the children achieved seroprotection antibodies to hepatitis B surface antigen (anti-HBsAG titers ≥ 10 mIU/ml) one month after primary vaccination. No difference was observed between vaccine responsiveness and age, gender, birthweight, maturity, duration of breastfeeding, exposure to HBsAg-positive family members, and mid-upper arm circumference (p > 0.05). HLA types, DRB 111 (64.7%), B5 (52.9%), DRB 104 (52.9%) and DRB 11001 (47%) were detected at increased frequency in non-responders. The antibody titers were significantly higher in children who breastfed for the first six months and longer and who were vaccinated concomitantly with other common vaccines. Conclusion: The seroprotection antibodies to hepatitis B surface antigen correlated with breast feeding and hepatitis B vaccination concomitant with other common vaccines. HLA types DRB 111, B5, DRB 104 and DRB 11001 had increased frequency in non-responders.