Evaluation of Immune Response to Hepatitis B Vaccine among Malnourished Children in Yemen

Objectives: To determine the coverage rate of hepatitis B virus (HBV) vaccine and to evaluate the immune response to HBV vaccine by measuring hepatitis B surface antibody (anti-HBs) among malnourished un-der-five-year old children. Methods: A cross-sectional study was conducted in two tertiary hospitals in Yemen; Al-Sabeen Maternity and Child Hospital in Sana’a and the Yemeni-Swedish Hospital in Taiz city in the period from March 2014 to Dec. 2014. The target population was malnourished children aged from 6 to 59 months old with a histo-ry of three HBV vaccine doses in infancy. According to the World Health Organization’s definition of malnu-trition, 121 malnourished children were enrolled in the study. Data of malnourished children were collect-ed using a pre-designed, pre-tested questionnaire. Two milliliters of venous blood were taken, and anti-HBs was then tested by enzyme linked immunosorbent assay. An anti-HBs level of at least 10 IU/L was considered a successful response to the vaccine. Results: The coverage rate of HBV vaccine among malnourished children was 89.3%, being higher among girls (52.1%) than boys (37.2%). Response to HBV vaccine (≥10 IU/L) was observed in 72.2% (78/108) of children while 27.8% (30/108) of children failed to respond to the vaccine, with a statistically significant difference (p <0.001). Conclusions: A good HBV vaccine coverage rate was found among malnourished Yemeni children, with a moderate rate of protection. Therefore, re-vaccination or administration of booster doses to a substantial proportion of vaccinated children should be considered.