Table 1.

Protective efficacy of the Hib vaccines in prospective randomized studies

VaccineCountryAge (mo) of vaccineesNo. of children vaccinatedNo. of Hib cases in:Efficacy (%)PCI95%Reference(s)
VaccineesControls
PolysaccharideFinland18–7137,39322090<0.00155, 98 129,131
Conjugates
 Diphtheria toxoid (PRP-D)Finland3, 4, 6110,00043794<0.00183, 98 46
U.S.A. (Alaska)2, 4, 62,10071243NS−43, 78 181
 Mutant diphtheria toxoid (PRP-CRM, HbOC)U.S.A.2, 4, 661,080022100<0.00171, 100 16
 Outer membrane protein (PRP-OMP)U.S.A.≈2, ≈34,16111493<0.00153, 98 146
 Tetanus toxoid (PRP-T)U.K.2, 3, 431,98311895<0.00174, 100 18