Comparison of the immune response of four different dosages of a yeast-recombinant hepatitis B vaccine in Singapore children : a four-year follow-up study

• Published in: Bulletin of the World Health Organization Vol. 70; no. 2; pp. 233 - 239
• Main Authors: GOH, K. T, TAN, K. L, KONG, K. H, OON, C. J, CHAN, S. H
• Format: Journal Article
• Language: English
• Published: Genève Organisation mondiale de la santé 01.03.1992; World Health Organization
• Subjects: Antibody Formation; Biological and medical sciences; Child; Child, Preschool; Children; Dosage and administration; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Hepatitis B - epidemiology; Hepatitis B - immunology; Hepatitis B - prevention & control; Hepatitis B Core Antigens - blood; Hepatitis B Core Antigens - immunology; Hepatitis B Surface Antigens - blood; Hepatitis B Surface Antigens - immunology; Hepatitis B vaccine; Humans; Immunization; Immunization of children; Infant; Microbiology; Population; Seroepidemiologic Studies; Singapore - epidemiology; Tropical medicine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccines, Synthetic - administration & dosage; Vaccines, Synthetic - immunology; Vaccines, Synthetic - therapeutic use; Viral Hepatitis Vaccines - administration & dosage; Viral Hepatitis Vaccines - immunology; Viral Hepatitis Vaccines - therapeutic use; Virology; Yeasts; Asia; Singapore; Human; Prevention; Immune response; Immunogenicity; Efficiency; Vaccination; Vaccine; Child; Posology; Comparative study; Public health; Immunologic Factors; Health Services; Singapore; Age Factors; Biology; Data Collection; Delivery Of Health Care; Research Methodology; Immunity; Vaccines > administraction and dosage; Population Characteristics; Population; Physiology; Demographic Factors; Antibodies > analysis; Immunization; Laboratory Examinations And Diagnoses; Health; Youth; Hepatic Effects > prevention and control; Examinations And Diagnoses; Studies; Asia; Southeastern Asia; Follow-up Studies; Developing Countries; Primary Health Care
• ISSN: 0042-9686; 1564-0604

The immunogenicity of four different dosages of yeast-derived hepatitis B vaccine (Merck, Sharp & Dohme: 0.6 micrograms, 1.25 micrograms, 2.5 micrograms and 5.0 micrograms), administered at 0, 1 and 6 months (0-1-6 schedule) intramuscularly, was evaluated in 122 seronegative healthy children 1-12 years of age. Three months after the first dose, 83.9-100% of the vaccinees seroconverted. Peak geometric mean titres (GMT) of between 1088 mlU/ml and 1699 mlU/ml were attained 3 months after completion of the vaccination schedule. After 24 months, anti-HBs (antibody to hepatitis B surface antigen) was detected in 93.1-100% of the vaccinees, but the GMT dropped to between 214.3 mlU/ml and 303.5 mlU/ml. After 48 months, 88.8-100% of the vaccinees continued to possess anti-HBs and 70.3-87% had titres above 10 mlU/ml. As expected, the GMT declined further to between 72.6 mlU/ml and 118.8 mlU/ml. There were no significant differences in seroconversion rates and GMT among the different dosage groups. All the vaccinees remained asymptomatic and free from hepatitis B virus infection. The study showed that reduced dosages of the vaccine (0.6 micrograms, 1.25 micrograms and 2.5 micrograms) were as immunogenic as the standard dose (5 micrograms); the 2.5-micrograms dose was recommended for the national childhood immunization programme in Singapore. No booster is necessary for at least four years after vaccination.