Immunogenicity of Haemophilus influenzae type b tetanus toxoid conjugate vaccine in young infants. The Kaiser-UCLA Vaccine Study Group

J Infect Dis. 1994 Jul;170(1):76-81. doi: 10.1093/infdis/170.1.76.


In a prospective, randomized, double-blind efficacy trial, the immunogenicity of 10 lots of Haemophilus influenzae type b capsular polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) was evaluated. More than 10,000 infants received PRP-T or hepatitis B vaccine at about 2, 4, and 6 months of age along with other childhood vaccines. In a subset of infants, geometric mean concentrations of total anticapsular antibody were 0.08, 0.79, and 5.29 micrograms/mL after the first, second, and third doses, respectively. Four lots of reconstituted lyophilized PRP-T vaccine were significantly more immunogenic than 6 lots of aqueous vaccine (P = .03). In a stepwise regression model, the most important additional factors affecting anticapsular antibody concentrations were the time between the third dose and the blood draw, race, and breast-feeding status at 6 months of age. Immune responses to diphtheria and tetanus toxoids were not significantly different for infants given PRP-T or hepatitis B vaccines along with diphtheria-tetanus toxoid-pertussis vaccine.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / immunology
  • Double-Blind Method
  • Female
  • Gestational Age
  • Haemophilus Vaccines / administration & dosage
  • Haemophilus Vaccines / immunology*
  • Haemophilus influenzae / immunology*
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Prospective Studies
  • Tetanus Toxoid / administration & dosage
  • Tetanus Toxoid / immunology*
  • Vaccines, Conjugate / immunology


  • Antibodies, Viral
  • Haemophilus Vaccines
  • Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate
  • Tetanus Toxoid
  • Vaccines, Conjugate