Serum Levels of Anti-Hepatitis B Surface Antibody Among Vaccinated Population Aged 1 to 18 Years in Ahvaz City Southwest of Iran

Background: the duration of protection following primary series vaccination against hepatitis b is unknown in children and adolescents. it has been shown that the level of anti-hepatitis b surface antigen antibodies (anti hbs ab) declines over years after vaccination. objectives: the aim of this study was to estimate the long-term immunity against hepatitis b virus infection among children and adolescents who had received a complete hepatitis b vaccination series during infancy. patients and methods: in a cross-sectional study, the - anti-hbsab levels of 840 vaccinated children and adolescents were determined by enzyme-linked immunosorbent assay. results: hepatitis b seroprotection rates (anti hbsab ≥ 10 iu/l) among vaccinated children and adolescents aged 1 and 18 years were 90% and 48.9%, respectively. the declining trend of geometric mean titer of anti-hbsab levels was observed as changed from 272.3 iu/l to 94.1 iu/l in 1 and 18-year-old population, respectively. a significant negative correlation was found between age and anti-hbsab levels (r = - 0.220, p = 0.0001). conclusions: the results showed a declining trend in anti-hbsab titers over the time after vaccination against hepatitis b virus in our region. further studies are warranted to establish the need for a booster dose in cases that are at risk of hepatitis b virus infection.