title: Efficacy of Haemophilus influenzae type b vaccines in Massachusetts children 18 to 59 months of age.
abstract: Since 1987 Haemophilus influenzae b (Hib) conjugate vaccines have been licensed for use in children ages 18 months and older. Before licensure there were no clinical trials of a single dose of any conjugate vaccine in children ages 18 months or older. To fulfill this need we performed an age- and residence-matched case-control study of the efficacy of Hib vaccines. In our study population the protective efficacy (PE) of Hib-diphtheria toxoid conjugate vaccine was 88% (95% confidence interval, 45 to 98%). No vaccine failures were observed with Hib oligosaccharide CRM197 diphtheria protein conjugate vaccine, but usage was not sufficient to establish efficacy: PE = 100% (95% confidence interval, -37 to 100%). The protective efficacy of Hib capsular polysaccharide vaccine was 18% (95% confidence interval -487 to 89%). We conclude that for children ages 18 to 60 months a single dose of the Hib conjugate vaccine, PRP-D, is protective against invasive Hib infections. Consistent with most studies Hib polysaccharide vaccine provided suboptimal protection.
authors.affiliation: Massachusetts Public Health Biologic Laboratories, Boston.
authors.forename: A M
authors.initials: AM
authors.lastname: Loughlin
authors.forename: C D
authors.initials: CD
authors.lastname: Marchant
authors.forename: S
authors.initials: S
authors.lastname: Lett
authors.forename: E D
authors.initials: ED
authors.lastname: Shapiro
mesh_terms: D016667:Bacterial Capsules; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D016022:Case-Control Studies; D002675:Child, Preschool; D004168:Diphtheria Toxoid; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000517:prevention & control; D018073:Haemophilus Vaccines; D006193:Haemophilus influenzae; D006801:Humans; D007223:Infant; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D011135:Polysaccharides, Bacterial; D013223:Statistics as Topic
chemical_list: D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; C052180:Haemophilus influenzae type b-polysaccharide vaccine-diphtheria toxoid conjugate; D011135:Polysaccharides, Bacterial; C061963:HibTITER protein, Haemophilus influenzae