Table 2.

Transplacental Transfer of Maternal Antibodies and Antibody Concentrations in LRTI+ and LRTI− Infants at Birth

	LRTI+		LRTI−
	Infant/mother antibody ratio
Respiratory pathogen	N	Mean (95% CI)	N	Mean (95% CI)	p
RSV	83	1.28 (1.12–1.47)	111	1.46 (1.30–1.65)	.09
PNC1	81	0.89 (0.83–0.95)	104	0.88 (0.83–0.94)	.64
PNC5	81	0.65 (0.59–0.71)	104	0.73 (0.66–0.80)	.06
PNC6B	81	0.76 (0.70–0.84)	104	0.75 (0.69–0.81)	.87
PNC14	81	0.91 (0.84–0.97)	104	0.89 (0.84–0.95)	.86

	Infant antibody concentrations at birth (EU/mL)
	N	GMC (95% CI)	N	GMC (95% CI)
Influenza A	86	54.7 (43.5–68.8)	111	50.6 (38.9–65.8)	.46
RSV	87	70.5 (55.2–90.0)	113	83.2 (68.8–100.6)	.28
PIV1	78	3.5 (2.0–5.9)	105	4.4 (2.9–6.6)	.14
PIV2	79	6.6 (4.0–10.9)	104	8.7 (5.8–13.0)	.54
PIV3	79	11.4 (7.5–17.4)	104	11.0 (7.6–16.0)	.80
PNC1	82	0.8 (0.7–0.9)	106	0.7 (0.6–0.7)	.11
PNC5	82	0.8 (0.7–0.9)	106	0.8 (0.7–0.9)	.82
PNC6B	82	0.7 (0.6–0.8)	106	0.7 (0.6–0.7)	.53
PNC14	82	2.9 (2.6–3.3)	106	2.8 (2.5–3.1)	.78

Bolded p values indicate marginal differences. To adjust for one-to-n matching, all p values were calculated by linear mixed-effects models.

N, no. of participants tested; GMC, geometric mean concentration; RSV, respiratory syncytial virus; PIV, parainfluenza; CI, confidence intervals.

EU, ELISA units.