Antibody titer in Iranian children 6 years after hepatitis B vaccine administration

ObjectiveThe purpose of study was to evaluate the immune response in a sample of vaccinated children aged 6 years.BackgroundAlthough immunization of infants against hepatitis B virus (HBV) is the most effective way to prevent infection, duration of the afforded immunization is unknown.MethodsThe immunity derived from the HBV vaccine was assessed by measuring the antibody in 3752 children who were vaccinated in a routine vaccination program in three cities of Iran (Isfahan, Khoramabad, Shahrekord).ResultsSeven hundred and twenty-three (19.3%) children had antibodies levels <10 MIU/mL and 1096 (29.2%) had antibodies levels ≥100 MIU/mL.The total GMT was 34.5 ± 0.66, and GMT was statistically different in non-immune and immune children (3.1 ± 0.36 versus 49.1 ± 0.52).No correlation was found between HbsAb titers and growth pattern during the first and sixth years of life, number of vaccine, time of vaccination and drug use.The predictors were low birth weight and chronic disease.ConclusionIt is recommended that high risk children should be monitored regularly for anti-HBS, and booster must be administrated, if necessary.