Table.

Baseline characteristics of 4 month old infants and rate of local reactions to immunisation over three days by needle used for vaccination. Values are numbers (percentages) of infants unless stated otherwise

Local reaction	Size of needle			Difference between longer and shorter needle
	23 G, 25 mm (n=53)	25 G, 16 mm (n=57)		Relative risk (95% CI); P value	Test for trend
Baseline characteristics
Mean (SD) weight (kg)*	6.7 (0.9)	6.8 (0.9)
Age at vaccination (weeks):
16-17	37 (70)	36 (63)
18-19	11 (21)	16 (28)
⩾20	5 (9)	5 (9)
Sex
Male	34 (64)	30 (53)
Female	19 (36)	27 (47)
Site of injection:
Left leg	13 (25)	12 (21)
Right leg	40 (75)	45 (79)
Vaccine type†:
0.5 ml	8 (15)	8 (14)
1.0 ml	45 (85)	49 (86)
Local reactions
Redness:
At 6 hours	21 (40)	34 (60)		0.66 (0.45 to 0.99); P=0.04	P=0.007
At 1 day	15 (28)	36 (63)		0.45 (0.28 to 0.72); P=0.0002	P<0.0001
At 2 days	5 (9)	22 (39)		0.24 (0.10 to 0.60); P=0.0004	P=0.0004
At 3 days	2 (4)	16 (28)		0.13 (0.03 to 0.56); P=0.0006	P=0.001
Swelling:
At 6 hours	12 (23)	33 (58)		0.39 (0.23 to 0.67); P=0.0002	P=0.0009
At 1 day	15 (28)	36 (63)		0.45 (0.28 to 0.72); P=0.0002	P=0.0001
At 2 days	10 (19)	29 (51)		0.37 (0.20 to 0.69); P=0.0005	P=0.0007
At 3 days	7 (13)	23 (40)		0.33 (0.15 to 0.70); P=0.001	P=0.002
Tenderness:
At 6 hours	9 (17)	16 (28)		0.60 (0.29 to 1.25); P=0.17	P=0.4
At 1 day	4 (8)	8 (14)		0.54 (0.17 to 1.68); P=0.3	P=0.4
At 2 days	0	3 (5)		0 (not estimable); P=0.09	P=0.4
At 3 days	0	1 (2)		0 (not estimable); P=0.3	P=0.2
Any local reaction	33 (62)	48 (84)		0.74 (0.58 to 0.94); P=0.009

^*Weight missing for three infants. 

^†0.5 ml vaccine=Pasteur Merieux DPT/Hib. 1 ml vaccine=Evans DPT reconstituting Wyeth Lederle Hib-Titer.