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.