Vaccination with a Haemophilus influenzae type b conjugate vaccine reduces oropharyngeal carriage of H. influenzae type b among Gambian children.
The effect of a Haemophilus influenzae type b (Hib) polyribosylribitol phosphate-tetanus toxoid conjugate vaccine (Hib/PRP-T) on oropharyngeal carriage of Hib was studied during an efficacy trial in Gambian infants. Children were vaccinated with Hib/PRP-T and diphtheria-tetanus toxoids-pertussis (DTP) or DTP alone at ages 2, 3, and 4 months. Groups of 1000 children aged 1-2 years were studied each year for 4 years. Hib was detected by production of a halo on antiserum agar plates. Carriage was significantly lower among children fully vaccinated with Hib/PRP-T given with DTP (4.4%; 95% confidence interval [CI], 3.8%-5.7%) than among children fully vaccinated with DTP alone (11.0%; 95% CI, 8.9%-13.0%) (protective effect adjusted by year = 60%; 95% CI, 44%-72%; P < .001). Hib carriage varied by year among nonvaccinated children. Hib conjugate vaccines are likely to produce a herd protective effect in underdeveloped communities, as recorded in Europe and the United States.
Adegbola
R A
RA
Medical Research Council Laboratories, Fajara, Banjul, The Gambia. radegbola@mrc.enda.sn
Mulholland
E K
EK
Secka
O
O
Jaffar
S
S
Greenwood
B M
BM
D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D005714:Gambia; D006192:Haemophilus Infections / Q000382:microbiology / Q000517:prevention & control*; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006193:Haemophilus influenzae / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D015999:Multivariate Analysis; D009960:Oropharynx / Q000382:microbiology*; D012307:Risk Factors; D013745:Tetanus Toxoid / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology*
D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate