Safety and immunogenicity of a recombinant hepatitis B vaccine administered to infants at 2, 4 and 6 months of age

A recombinant hepatitis B vaccine was administered to over 5000 infants in a prospective, randomized and blinded study. Infants were given either recombinant hepatitis B vaccine (Engerix-B®, SmithKline Beecham Pharmaceuticals, 10 μg dose^-1) or a Haemophilus influenzae type b (Hib) conjugate vaccine at 2, 4 and 6 months of age simultaneously with diphtheria-tetanus-pertussis and oral polio vaccines. Adverse reactions were ascertained by parental reports and interviews, and review of medical records. Blood specimens collected from 269 infants given hepatitis B vaccine were assayed for antibody to hepatitis B surface antigen (anti-HBs) by enzyme immunoassay. Infants given hepatitis B vaccine experienced low rates of adverse reactions that were similar or lower than the rates in infants given Hib conjugate vaccine. The geometric mean anti-HBs concentrations were 9.6 mIU ml^-1 after one dose, 333 mIU ml^-1 after two doses and 1812 mIU ml^-1 after three doses (99% had levels ≤10 mIU ml^-1). Antibody responses to diphtheria and tetanus toxoids were unaffected by simultaneous administration of hepatitis B or Hib conjugate vaccine. Engerix-B vaccine was safe and immunogenic when given with Other routine childhood immunizations at 2, 4 and 6 months of age, and should provide long-term protection against hepatitis B virus infection.