Table 4:

Neonatal outcomes, by study period

Variable	Control vaccine		Influenza vaccine		OR (95% CI)^*	p value	Adjusted OR (95% CI)^*^†	p value^‡

	No.	% (95% CI)^*	No.	% (95% CI)^*
No influenza virus circulating (Sept. 2004–Jan. 2005)		n = 108		n = 103

Birth weight, g, mean	–	3053 (2967 to 3139)	–	3083 (3000 to 3176)	30 (−98 to 157)^**	0.9^††	–

Small for gestational age^§	37	34.3 (25.1 to 42.9)	30	29.1 (20.2 to 37.8)	0.79 (0.44 to 1.41)	0.4	–

Born before 37 weeks’ gestation	10	9.3 (3.8 to 14.8)	8	7.8 (2.6 to 13.0)	0.83 (0.31 to 2.18)	0.7	–

Weight < 2500 g	8	7.4 (2.5 to 12.3)	6	5.8 (1.3 to 10.3)	0.77 (0.26 to 2.31)	0.6	–

Apgar score at 1 min, mean	–	7.7 (7.3 to 8.1)	–	7.6 (7.3 to 8.1)	–	0.7	–

Female	46^¶	42.9 (32.7 to 51.3)	43	41.8 (31.5 to 50.5)	0.97 (0.56 to 1.67)	0.9	–

Influenza virus circulating (Feb. 2005–Oct. 2005)		n = 58		n = 58

Birth weight, g, mean	–	2978 (2849 to 3107)	–	3178 (3058 to 3298)	200 (191 to 209)^**	0.02^††	193 (9 to 378)^‡‡	0.01

Small for gestational age^§	26	44.8 (31.2 to 56.8)	15	25.9 (13.9 to 36.1)	0.43 (0.20 to 0.94)	0.03	0.44 (0.19 to 0.99)	0.05

Born before 37 weeks’ gestation	4	6.9 (0.4 to 13.4)	2	3.5 (0 to 8.2)	0.48 (0.08 to 2.74)	0.4	0.32 (0.05 to 2.29)^§§	0.3

Weight < 2500 g	5	8.6 (1.4 to 15.8)	1	1.7 (0 to 5.0)	0.19 (0.02 to 1.64)	0.09	0.17 (0.02 to 1.63)	0.1

Apgar score at 1 min, mean	–	7.3 (6.6 to 8.0)	–	7.7 (7.3 to 8.2)	–	0.3	–

Female	26	44.8 (31.2 to 56.8)	27	46.6 (33.2 to 58.9)	1.07 (0.52 to 2.23)	0.9	1.12 (0.53 to 2.39)	0.8

Note: CI = confidence interval, OR = odds ratio.
↵* Unless stated otherwise.
↵† Adjusted for gestational age at immunization, and interval from immunization to delivery.
↵‡ χ² test.
↵§ Infants who were below the tenth percentile of weight for gestational age.
↵¶ Calculated from a total of 107 infants due to missing sex data for one infant.
↵** Mean difference (95% CI).
↵†† Mann–Whitney U test.
↵‡‡ Adjusted mean difference.
↵§§ Adjusted only for interval from immunization to delivery.