The prevalence of hepatitis B virus infection in Nigerian children prior to vaccine introduction into the National Programme on Immunization schedule

INTRODUCTION Hepatitis B virus infection is a major global health problem of public health importance. In a bid to control the infection, the Nigerian government in 2004 introduced hepatitis B vaccine into the National Program on Immunization. There are no studies on the prevalence of hepatitis B in adolescent prior to 2004. The study was aimed at determining the seroprevalence and predictors of viral Hepatitis B in Nigerian children aged 11-19 years. METHODS A cross sectional analytical study was conducted in July 2014. Multi-staged sampling technique was used to select 749 children from six secondary schools in Calabar, Cross River State, Nigeria. Ethical clearance was obtained from the Cross River State Medical Ethical Committee. A validated structured interviewer administered questionnaire was used to obtain information from participants following parental consent. Blood samples were obtained for qualitative detection of HBsAg using rapid chromatographic immunoassays with test kits from ABON (China) having sensitivity, specificity and accuracy of >99%, 97% and 98.5% respectively. Data was analyzed using SPSS version 20.2. RESULTS Nine of the749 students screened were positive for HBsAg giving an overall prevalence of 1.2%. The sex specific prevalence was 0.8% for males and 1.8% for females. After multivariate analysis, age was the predictor of hepatitis B infection (OR 3.92; 95% CI 1.22-12.63; p-value 0.02). CONCLUSION The prevalence of HBV infection was low. Despite the low prevalence, the introduction of the vaccine is justifiable in view of the public health importance of the infection.