Protective efficacy of Haemophilus influenzae type b polysaccharide and conjugate vaccines in children 18 months of age and older.
To evaluate the protective efficacy of polyribosylribitol phosphate (PRP) and polyribosylribitol phosphate-diphtheria toxoid (PRP-D) vaccines in children 18 to 59 months of age, we conducted a case-control study in Los Angeles (Calif) County between July 1, 1988, and July 31, 1989. Seventy-nine children with invasive Haemophilus influenzae type b disease 18 to 59 months of age were identified, and 212 controls were selected by random-digit telephone dialing methods. Cases and controls were stratified by age and month of disease onset of the case. Seventeen PRP vaccine failures and two PRP-D vaccine failures occurred more than 2 weeks after vaccination. The PRP vaccine was shown not to be effective (point estimate--47%; 95% confidence interval,--307% to 47%), but the PRP-D vaccine was 88% protective (95% confidence interval, 42% to 97%). Adjustment of the efficacy estimates for potential confounding variables did not change the results significantly. The PRP-D vaccine provided significantly better protection than the PRP vaccine against invasive H influenzae type b disease in this population.
Greenberg
D P
DP
UCLA Center for Vaccine Research, Harbor-UCLA Medical Center, UCLA School of Medicine 90502.
Vadheim
C M
CM
Bordenave
N
N
Ziontz
L
L
Christenson
P
P
Waterman
S H
SH
Ward
J I
JI
D016667:Bacterial Capsules; D001428:Bacterial Vaccines; D016022:Case-Control Studies; D002675:Child, Preschool; D004168:Diphtheria Toxoid; D004341:Drug Evaluation; D006192:Haemophilus Infections / Q000453:epidemiology / Q000517:prevention & control*; D018073:Haemophilus Vaccines; D006193:Haemophilus influenzae; D006801:Humans; D007223:Infant; D016015:Logistic Models; D015141:Los Angeles / Q000453:epidemiology; D008583:Meningitis, Haemophilus / Q000453:epidemiology / Q000517:prevention & control; D016017:Odds Ratio; D011014:Pneumonia / Q000453:epidemiology / Q000517:prevention & control; D011135:Polysaccharides, Bacterial; D011159:Population Surveillance; D011897:Random Allocation
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