Background: Few data are available concerning the long term immunogenicity of the pediatric doses of hepatitis B vaccines.
The aim: was to evaluate the immune response among school aged children after hepatitis B vaccination according to Expanded Program on Immunization (EPI) in Egypt, and to determine factors influencing the immune response to hepatitis B vaccine.
Subjects and Methods: This study included 300 healthy school aged children who had been given three doses of hepatitis B vaccine at 2,4 and 6 months of age during obligatory immunization schedule in Egypt. HBs antibody concentration was quantitated using Enzyme Linked ImmunoSorbent Assay (ELISA) and for seronegative cases (Anti-HBs Ab10 mIU/ml). HBs Ab titre decrease significantly with increasing age and with increase duration post vaccination as seroprotection rates (>10 mIU/ml)in studied subjects from 6-10 years old, from 10-13 years old and from 13-17 years old were 69.5%, 25.2% and 5.3% respectively, also statistically significant decrease was found in males than females. There was no significant association between HBs Ab titre and other factors that affect the immune response to HB vaccine such as smoking, obesiry, residence, social class and any medical condition associated with reduced immune state. HBs Ag was negative in 100% of studied seronegative children.
Conclusion: Our results revealed that 43.7%of the studied children were HBV seroprotective . HBs Ab titre decrease significantly with increasing age, duration after vaccination and with male gender. Booster dose of hepatitis B vaccine should be considered to enhance the immune protection of the vaccine especially in our endemic area.
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