title: Immunological characterization of conjugated Haemophilus influenzae type b vaccine failure in infants.
abstract: Infant vaccination with conjugated Haemophilus influenzae type b (Hib) vaccine is highly effective in protecting against invasive Hib infections, but vaccine failures do occur. Twenty-one vaccine failures are reported since the introduction of the Hib conjugate vaccine in The Netherlands. Of the 14 evaluable patients, 6 children showed no antibody response to Hib polysaccharide in convalescent-phase serum (immunoglobulin [Ig] G anti-Hib level <1.0 microg/mL), including 1 child with hypogammaglobulinemia and 1 child with IgG2 deficiency. After revaccination, almost all children developed anti-Hib antibodies. In case of Hib vaccine failure, case investigation should be performed, including measurement of serum Ig concentrations as well as specific anti-Hib antibodies. Invasive Hib disease after infant conjugate Hib vaccination may be the presentation of an underlying immunodeficiency, but more often, only a decreased antibody response to Hib is found; revaccination with conjugated Hib vaccine is advised.
authors.affiliation: Department of Immunology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands. m.breukels@azu.nl
authors.forename: M A
authors.initials: MA
authors.lastname: Breukels
authors.forename: L
authors.initials: L
authors.lastname: Spanjaard
authors.forename: L A
authors.initials: LA
authors.lastname: Sanders
authors.forename: G T
authors.initials: GT
authors.lastname: Rijkers
mesh_terms: D000293:Adolescent; D000328:Adult; D016667:Bacterial Capsules; D002648:Child; D005260:Female; D018073:Haemophilus Vaccines / Q000276:immunology*; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D008297:Male; D008583:Meningitis, Haemophilus / Q000517:prevention & control*; D008875:Middle Aged; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D017211:Treatment Failure; D018074:Vaccines, Conjugate / Q000276:immunology*
chemical_list: D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D011135:Polysaccharides, Bacterial; D018074:Vaccines, Conjugate