THE IMMUNE RESPONSE TO HEPATITIS B VACCINE IN CHILDREN IN SHARKIA

Background:The duration of protection after hepatitis B vaccination of infants is unknown.Methods:We assessed (anti-HBs) among 200 Egyptian children. They were at low risk of exposure to HBV infection. They had been vaccinated with hepatitis B vaccine in infancy through compulsory vaccination program with recombinant hepatitis B vaccine intramuscular injection at 2, 4, 6 months in conjunction with DPT-polio vaccine They were classified into two groups each contains 100 children. The 1st group included infants at least 2 months after completion of 3 doses of the vaccine (>8 months).The 2nd group included school age children aged 6-12 years old. Those with nonprotective titers (<10 mIU/mL) received a booster dose we investigated the factors associated with immunity.Sera were obtained from all children and tested for (Anti-Hbs) and (anti-HBc) and ferritin.Results:Positive rate of Anti-Hbs in group П was 52% which is statistically significant lower than the initial responders rate of 83% in group І. Moreover, Mean concentration of Anti-Hbs is significantly decreased with age. A mean titer of 48.9 ±15.8 mIU/ml in group І is decreased to 12.6 ± 5.2 mIU/ml in group П. Moreover within the 2nd group, a negative correlation between Anti-Hbs Ab mean level and age in years