Immunogenicity, reactogenicity and comparison of two doses of recombinant DNA yeast-derived hepatitis B vaccine in Ethiopian children.

Hepatitis B virus infection and its sequelae, chronic hepatitis, cirrhosis of the liver and primary hepatocellular carcinoma (PHC), are important medical problems in Ethiopia. There is a possibility to prevent these by mass immunization of neonates and children. To achieve this, the cost of the hepatitis B vaccine must be possible within the limited health budget of the country. This study, therefore, was conducted to find out comparative safety and immunogenicity of two doses, 10 mcg and 20 mcg, of recombinant DNA yeast-derived hepatitis B vaccine in children, 2-14 years old. Three hundred and fourteen non-immune children, from an initial sample of 380 children, were grouped into those below and those above 8 years of age. Each group was further subdivided into boys and girls and each group was given either 10 mcg or 20 mcg hepatitis B vaccine, alternately, using the 0-1-6 months schedule. Anti-HBs titres were determined at one, two and seven months. Side effects were recorded by parents for three days following each injection. Comparison of seroconversion rates (97-100%) and anti-HBs geometric mean titres (3421-6336) of boosted vaccinees in the different sex, age and dose groups showed no significant differences. There were minor side effects recorded in 76 children. Therefore, the 10 mcg and 20 mcg doses of recombinant DNA yeast-derived hepatitis B vaccine are equally safe and highly immunogenic in children 3-14 years of age.