Table 1

Hib IgG GMC, with 95% CI, following primary immunisations, a 4th dose, and at time of study for subjects who did or did not receive a booster dose of Hib in infancy, and proportions achieving concentrations ⩾0.15 and 1.0 µg/ml at time of study

	n	Hib IgG GMC, µg/ml (95% CI)					p value
	n	After primary immunisation	After booster dose	At time of study	⩾0.15 n (%)	⩾1.0 n (%)	p value
*t test comparing Hib IgG after booster dose and at time of study in subjects who had received a booster dose in infancy.
†t test comparing Hib IgG at time of study in subjects who had Hib IgG <0.15 or ⩾0.15 µg/ml after primary immunisations.
Boosted infants: All	26	0.18 (0.13 to 0.26)	3.42 (1.65 to 7.10)	0.23 (0.14 to 0.39)	14 (26%)	2 (8%)	<0.0001*
Boosted infants: Post-primary <0.15	12	0.08 (assigned)	1.21 (0.42 to 3.51)	0.25 (0.09 to 0.71)	5 (42%)	2 (17%)	0.80†
Boosted infants: Post-primary ⩾0.15	14	0.37 (0.28 to 0.50)	8.30 (3.00 to 19.14)	0.22 (0.14 to 0.37)	9 (75%)	0 (0%)	0.80†
Non-boosted infants	7	1.60 (1.18 to 2.18)	NA	0.25 (0.04 to 1.61)	2 (29%)	2 (29%)