RESUMO
BACKGROUND: Childhood immunization against hepatitis B is one of the most effective strategies for reducing the global burden of chronic hepatitis B infection and its sequelae. There are limited data from India on both the anti-Hep B antibody titres in children after vaccination and the age-related decline in the titres. This study was planned to estimate the proportion of children in the age group of 1-10 years who develop protective levels of anti-hepatitis B antibodies after childhood vaccination and to examine the change in antibody titres with age in these children. METHODS: A hospital-based cross-sectional study was carried out in children admitted to the hospital for various ailments. Basic demographic data, vaccination history and HBsAg status of the mother were recorded. All the enrolled children were evaluated for HBsAg and anti hepatitis B surface antibody (anti-HBS) titres. Institutional ethical clearance was obtained, and informed consent from the parents of the children was taken before drawing samples. RESULTS: We found that 68.86% Confidence Interval ((CI): 59.8-76.8%) of the children showed protective antibody titres after vaccination, while 31.14% (CI: 23.1-40.2%) of the children had titres less than 10 IU/L. Although 100% of children in the age group from birth to three years had titres more than 10 IU/L, this percentage showed a decline across the age groups, and 60% of children aged 9-10 years had titres less than 10 IU/L. CONCLUSION: Childhood vaccination against hepatitis B is effective in 68% children, and the antibody levels showed a steady decline with increasing age.