The impact of conjugate vaccine on carriage of Haemophilus influenzae type b

J Infect Dis. 1995 Jan;171(1):93-8. doi: 10.1093/infdis/171.1.93.


Conjugate vaccines against Haemophilus influenzae type b (Hib) may modify Hib pharyngeal colonization. Hib colonization was compared in 371 infants and their families. In Oxfordshire, infants received PRP-T (polyribosylribitol phosphate conjugated to tetanus toxoid) and in Buckinghamshire they did not (controls). Infants were followed at 6, 9, and 12 months of age. Also, 6 unvaccinated Hib carriers were vaccinated and followed for 6 weeks. Hib acquisition was lower in vaccinees than controls (P < .01). During surveillance, 1.5% of vaccinees and 6.3% of controls carried Hib (P = .04). Among those with family Hib exposure, the carriage rates were 8.7% and 38.5% (P = .07), respectively. Hiv carriage rates were lower among vaccinees' unvaccinated siblings. Giving conjugate vaccine to a child carrying Hib did not rapidly terminate carriage. Thus, a primary means by which herd immunity to Hib is induced in a vaccinated population may be through reduction or delay in the initial acquisition of Hib.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Capsules
  • Carrier State / prevention & control*
  • Case-Control Studies
  • Cohort Studies
  • Family Health
  • Female
  • Haemophilus Infections / prevention & control*
  • Haemophilus Vaccines* / immunology
  • Haemophilus influenzae / isolation & purification*
  • Humans
  • Infant
  • Male
  • Mothers
  • Nuclear Family
  • Pharynx / microbiology*
  • Surveys and Questionnaires
  • Tetanus Toxoid* / immunology
  • Vaccination
  • Vaccines, Conjugate / immunology


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