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 under-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 history of three HBV vaccine doses in infancy. According to the World Health Organization’s definition of malnutrition, 121 malnourished children were enrolled in the study. Data of malnourished children were collected 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.