title: The impact of conjugate vaccine on carriage of Haemophilus influenzae type b.
abstract: 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.
authors.affiliation: Department of Paediatrics, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
authors.forename: M L
authors.initials: ML
authors.lastname: Barbour
authors.forename: R T
authors.initials: RT
authors.lastname: Mayon-White
authors.forename: C
authors.initials: C
authors.lastname: Coles
authors.forename: D W
authors.initials: DW
authors.lastname: Crook
authors.forename: E R
authors.initials: ER
authors.lastname: Moxon
mesh_terms: D016667:Bacterial Capsules; D002353:Carrier State / Q000517:prevention & control*; D016022:Case-Control Studies; D015331:Cohort Studies; D005192:Family Health; D005260:Female; D006192:Haemophilus Infections / Q000517:prevention & control*; D018073:Haemophilus Vaccines / Q000276:immunology; D006193:Haemophilus influenzae / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D008297:Male; D009035:Mothers; D009679:Nuclear Family; D010614:Pharynx / Q000382:microbiology*; D011795:Surveys and Questionnaires; D013745:Tetanus Toxoid / Q000276:immunology; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate