title: Immunogenicity of a fourth dose of Haemophilus influenzae type b (Hib) conjugate vaccine and antibody persistence in young children from the United Kingdom who were primed with acellular or whole-cell pertussis component-containing Hib combinations in infancy.
abstract: In response to the rising incidence of Haemophilus influenzae type b (Hib) disease in the United Kingdom, a national campaign to give a booster dose of single-antigen Hib conjugate vaccine to children aged 6 months to 4 years was undertaken in 2003. Children (n = 386) eligible for Hib vaccine in the campaign were recruited. Hib antibody concentrations were measured before boost and at 1 month, 6 months, 1 year, and 2 years after boost and were analyzed according to children's ages at booster dose and whether a Hib combination vaccine containing acellular pertussis (aP) or whole-cell pertussis (wP) components was given in infancy. The geometric mean antibody concentrations (GMCs) before the booster declined as the time since primary immunization increased (P < 0.001), and GMCs were threefold higher in recipients of wP-Hib than aP-Hib combination vaccines (P < 0.001). GMCs 1 month after the booster increased with age (P < 0.001) as follows: 6 to 11 months; 30 microg/ml (95% confidence interval [CI], 22 to 40); 12 to 17 months, 68 microg/ml (95% CI, 38 to 124); and 2 to 4 years, 182 microg/ml (151 to 220), with no difference according to the type of priming vaccine received. Antibody levels declined after the booster, but 2 years later, GMCs were more than 1.0 microg/ml for all age groups. By extrapolating data for the decline in antibody levels, we found the GMCs 4 years after boosting were predicted to be 0.6, 1.4, and 2.6 microg/ml for those boosted at 6 to 11 months, 12 to 17 months, and 2 to 4 years, respectively, with levels of at least 0.15 microg/ml in about 90% of individuals. A booster dose of Hib vaccine given after the first year of life should provide long-lasting protection.
authors: Immunisation Department, Centre for Infections, Health Protection Agency, London NW9 5EQ, United Kingdom. jo.southern@hpa.org.uk
authors: Jo
authors: J
authors: Southern
authors: Jodie
authors: J
authors: McVernon
authors: David
authors: D
authors: Gelb
authors: Nick
authors: N
authors: Andrews
authors: Rhonwen
authors: R
authors: Morris
authors: Annette
authors: A
authors: Crowley-Luke
authors: David
authors: D
authors: Goldblatt
authors: Elizabeth
authors: E
authors: Miller
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D002675:Child, Preschool; D004306:Dose-Response Relationship, Immunologic; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods*; D007223:Infant; D008583:Meningitis, Haemophilus / Q000276:immunology / Q000517:prevention & control*; D010567:Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology*; D006113:United Kingdom; D022282:Vaccines, Acellular / Q000008:administration & dosage / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D018073:Haemophilus Vaccines; D010567:Pertussis Vaccine; D022282:Vaccines, Acellular; D014613:Vaccines, Attenuated; D018074:Vaccines, Conjugate
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