Haemophilus influenzae type b reemergence after combination immunization

Emerg Infect Dis. 2006 Jun;12(6):937-41. doi: 10.3201/eid1206.051451.


An increase in Haemophilus influenzae type b (Hib) in British children has been linked to the widespread use of a diphtheria/tetanus/acellular pertussis combination vaccine (DTaP-Hib). We measured anti-polyribosyl-ribitol phosphate antibody concentration and avidity before and after a Hib booster in 176 children 2-4 years of age who had received 3 doses of DTP-Hib (either DT whole cell pertussis-Hib or DTaP-Hib) combination vaccine in infancy. We also measured pharyngeal carriage of Hib. Antibody concentrations before and avidity indices after vaccination were low (geometric mean concentration 0.46 mug/mL, 95% confidence interval [CI] 0.36-0.58; geometric mean avidity index 0.16, 95% CI 0.14-0.18) and inversely related to the number of previous doses of DTaP-Hib (p = 0.02 and p<0.001, respectively). Hib was found in 2.1% (95% CI 0.7%-6.0%) of study participants. Our data support an association between DTaP-Hib vaccine combinations and clinical Hib disease through an effect on antibody concentration and avidity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / blood
  • Antibody Affinity
  • Bacterial Capsules
  • Child, Preschool
  • Diphtheria-Tetanus-acellular Pertussis Vaccines / immunology*
  • Haemophilus Infections / epidemiology*
  • Haemophilus Infections / immunology*
  • Haemophilus Vaccines / immunology*
  • Haemophilus influenzae type b / immunology*
  • Humans
  • Immunization / methods
  • Pharynx / virology
  • Polysaccharides, Bacterial / immunology*
  • Statistics, Nonparametric
  • United Kingdom / epidemiology
  • Vaccines, Conjugate / immunology


  • Antibodies, Viral
  • Diphtheria-Tetanus-acellular Pertussis Vaccines
  • Haemophilus Vaccines
  • Haemophilus influenzae type b polysaccharide vaccine
  • Polysaccharides, Bacterial
  • Vaccines, Conjugate