The impact of conjugate vaccine on carriage of Haemophilus influenzae type b.
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.
Barbour
M L
ML
Department of Paediatrics, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
Mayon-White
R T
RT
Coles
C
C
Crook
D W
DW
Moxon
E R
ER
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
D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate