title: Depression of anticapsular antibody after immunization with Haemophilus influenzae type b polysaccharide-diphtheria conjugate vaccine.
abstract: Invasive Haemophilus influenzae type b infections have been observed in the week after immunization with capsular polysaccharide vaccine. We sought to document depression of antibody concentrations after immunization of 18-month-old infants with H. influenzae type b capsular polysaccharide-diphtheria conjugate vaccine. All 9 infants with detectable preimmunization anticapsular antibody had depression of antibody concentrations on the second day after immunization (P = 0.002). By Day 7 all had achieved anticapsular antibody concentrations greater than 0.15 micrograms/ml, a level believed to provide protection to immediate challenge with H. influenzae type b. Of those without detectable preimmunization antibody, 7 of 21 (33%; 95% confidence interval, 11 to 56%) had not achieved concentrations of greater than 0.15 mg/ml 1 week after immunization. We conclude that there is depression of anticapsular antibody concentrations during the first week after immunization with H. influenzae type b capsular polysaccharide-diphtheria conjugate vaccine. We speculate that H. influenzae type b infections after immunization with H. influenzae type b vaccines may be the result of: (1) low antibody concentrations because of either depression of antibody concentrations or failure to develop antibody; and (2) exposure to H. influenzae type b. Depression of antibody concentrations could be explained by binding of in vivo antibody to the vaccine.
authors: Department of Pediatrics, St. Boniface General Hospital, Winnipeg, Canada.
authors: C D
authors: CD
authors: Marchant
authors: E
authors: E
authors: Band
authors: J E
authors: JE
authors: Froeschle
authors: P H
authors: PH
authors: McVerry
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis*; D000942:Antigens, Bacterial / Q000652:urine*; D016667:Bacterial Capsules; D001428:Bacterial Vaccines / Q000276:immunology*; D004168:Diphtheria Toxoid / Q000276:immunology*; D005260:Female; D018073:Haemophilus Vaccines; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D011135:Polysaccharides, Bacterial / Q000276:immunology* / Q000652:urine; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; C052180:Haemophilus influenzae type b-polysaccharide vaccine-diphtheria toxoid conjugate; D011135:Polysaccharides, Bacterial