Prevalence of anti hepatitis B surface antibody among children in Ahvaz,Iran, five years after vaccination

Introduction and objective: The public vaccination program of hepatitis B virus was started in 1993 in Iran, and all children received three doses of hepatitis B vaccine in 0, 2 and 6 months of age routinely. The objective of this study was to determine the prevalence of antibody to hepatitis B surface (anti-HBs) five years after vaccination. Materials and methods: In a cross-sectional study, anti-HBs was determined in six year old girl and boy students of selected elementary schools of Ahvaz with enzyme-linked immunosorbent assay (ELISA) method in 2006. All children had received complete course of hepatitis B vaccination in the first year of age. Results: Four hundred and twenty seven students (223 girls and 204 boys) were enrolled in the study. Of them, 75.4% were anti-HBs positive ( 10 mIU/mL). The prevalence of anti-HBs was statistically different between males and females (P=0.02).Conclusion: The study detected anti-HBs in 75.4% of children and because of possibility of presence of anamnestic responses in seronegative subjects, a booster dose of vaccine is not necessary at least five years after primary vaccination. Further studies are needed to evaluate hepatitis B immunity in older age groups.