Avidity maturation of antibody to Haemophilus influenzae type b (Hib) after immunization with diphtheria-tetanus-acellular pertussis-hib-hepatitis B combined vaccine in infants

J Infect Dis. 1999 Oct;180(4):1390-3. doi: 10.1086/314989.


Antibody avidity to Haemophilus influenzae type b (Hib) polysaccharide (PS) was assessed in infants vaccinated with diphtheria-tetanus-acellular pertussis (DTaP) combined with Hib-PS conjugated to tetanus toxoid (PRP-T) and hepatitis B (HB) (DTaP-PRP-T-HB) and after a PRP-conjugate (CRM197-OS) booster 3-7 months later. Avidity differed between infants with anti-Hib-PS IgG antibody <1 or >1 microg/mL postprimary series (avidity index [AI], 42%, 95% confidence interval [CI], 35%-49%, and 68% and 63%-72%, respectively; P<.0001). For infants with <1 microgram/mL anti-Hib-PS IgG antibody, mean AI rose by the time of preboost immunization to 61% (95% CI, 57%-65%), even though total IgG antibody levels fell. Spontaneous Hib-PS antibody rises after primary series DTaP-PRP-T-HB vaccination were followed by high postboost anti-Hib-PS IgG antibody levels and avidity. The DTaP-PRP-T-HB combination vaccine studied elicits high avidity antibody, and affinity maturation appears to occur in the absence of further antigen exposure even in those with very low anti-Hib-PS antibody.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibody Affinity*
  • Antibody Formation
  • Confidence Intervals
  • Diphtheria-Tetanus-Pertussis Vaccine / immunology*
  • Haemophilus Vaccines / immunology*
  • Haemophilus influenzae / classification
  • Haemophilus influenzae / immunology*
  • Hepatitis B Vaccines / immunology*
  • Humans
  • Immunization Schedule
  • Immunization, Secondary
  • Immunoglobulin G / blood*
  • Infant
  • Vaccines, Conjugate / immunology*


  • Diphtheria-Tetanus-Pertussis Vaccine
  • Haemophilus Vaccines
  • Hepatitis B Vaccines
  • Immunoglobulin G
  • Tetracel
  • Vaccines, Conjugate
  • diphtheria-tetanus-acellular pertussis-Hib-hepatitis B vaccine