Table 2. The effectiveness of palivizumab prophylaxis for RSV infections within 6 months and 12 months after discharge.

Characteristics	Before matching			After matching
	Study group(n = 127)	Control group(n = 347)	P value	Study group(n = 127)	Control group(n = 127)	P value
Within 6 months
Hospitalization for RSV infection, No. (%)	2 (1.6)	33 (9.5)	0.006	2 (1.6)	15 (11.8)	0.003
Receiving ICU care, No. (%)	1 (0.8)	15 (4.3)	0.11	1 (0.8)	9 (7.1)	0.024
Intubation and IMV, No. (%)	0 (0.0)	4 (1.2)	0.52	0 (0.0)	4 (3.1)	0.13
Nasal CPAP, No. (%)	1 (0.8)	2 (0.6)	0.69	1 (0.8)	1 (0.8)	0.29
NIPPV, No. (%)	0 (0.0)	5 (1.4)	0.39	0 (0.0)	3 (2.4)	0.19
Onset after discharge, month, median (IQR)	4.5 (4.5–4.5)	1.9 (0.6–3.5)	0.44	4.5 (4.5–4.5)	1.0 (0.4–2.5)	0.076
Length of ICU stay, median (IQR)	8.0 (8.0–8.0)	10.0 (5.0–13.0)	1.0	8.0 (8.0–8.0)	10.0 (4.5–13.0)	1.0
Length of stay, day, median (IQR)	7.0 (3.5–10.5)	11.0 (7.5–17.0)	0.55	7.0 (3.5–10.5)	13 (8.0–21.0)	0.31
Within 12 months
Hospitalization for RSV infection, No. (%)	5 (3.9)	45 (13.0)	0.004	5 (3.9)	20 (15.7)	0.003
Receiving ICU care, No. (%)	1 (0.8)	16 (4.6)	0.09	1 (0.8)	10 (7.9)	0.014
Intubation and IMV, No. (%)	0 (0.0)	4 (1.2)	0.52	0 (0.0)	4 (3.1)	0.13
Nasal CPAP, No. (%)	1 (0.8)	2 (0.6)	0.69	1 (0.8)	1 (0.8)	0.29
NIPPV, No. (%)	0 (0.0)	5 (1.4)	0.39	0 (0.0)	3 (2.4)	0.19
Onset after discharge, month, median (IQR)	6.9 (4.5–9.0)	3.1 (1.0–6.6)	0.059	6.9 (4.5–9.0)	2.5 (0.6–9.1)	0.24
Length of ICU stay, median (IQR)	8.0 (8.0–8.0)	9.0 (4.5–12.8)	1.0	8.0 (8.0–8.0)	9.0 (4.0–13.0)	1.0
Length of stay, day, median (IQR)	7.0 (3.5–10.5)	9.0 (7.0–14.5)	0.45	7.0 (3.5–10.5)	9.5 (6.3–18.0)	0.19

Abbreviations: CPAP, continuous positive airway pressure; ICU, intensive care unit; IMV, intermittent mandatory ventilation; NIPPV, nasal intermittent positive pressure ventilation; IQR, interquartile range; No., number.