Hepatitis B Vaccination and Factors Related with Unresponsiveness in Healthy Children

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 mu g 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. Postvaccination 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.