Table 1.

Demographic and clinical characteristics of pH1N1 and seasonal influenza

Characteristic	pH1N1 wave 1 versus wave 2			pH1N1 versus seasonal influenza
	pH1N1 wave 1 (n=58)	pH1N1 wave 2 (n=118)	p Value	pH1N1 total (n=176)	Seasonal, (n=200)	p Value
Sex, male, n (%)	35 (60)	72 (61)	0.93	107 (61)	108 (54)	0.18
Age, years, median (IQR)	6.4 (3.4–10.1)	6.5 (2.9–11.4)	0.81	6.5 (3.0–10.6)	3.3 (1.4–7.8)	<0.01
Age group, years, n (%)
<2	8 (14)	23 (19)	0.35	31 (18)	74 (37)	<0.01
2 to <5	13 (22)	24 (20)	0.75	37 (21)	54 (27)	0.18
≥5	37 (64)	71 (60)	0.64	108 (61)	72 (36)	<0.01
Admitted to ICU
No. (%) of children	12 (21)	20 (17)	0.36	32 (18)	31 (15)	0.49
Age, years, median (IQR)	5.8 (3.2–7.3)	9.2 (5.4–11.4)	0.13	7.3 (4.0–10.6)	3.6 (1.5–9.7)	0.02
Required mechanical ventilation
No. (%) of children	7 (12)	11 (9)	0.57	18 (10)	19 (10)	0.81
No. (%) of children admitted to ICU	7 (58)	11 (55)	0.85	18 (56)	19 (61)	0.69
Required supplemental oxygen
No. (%) of children	26 (47)	33 (28)	0.01	59 (34)	NA	NA
Duration of oxygen, days, median (IQR)	4 (2–6)	3 (2–7)	0.73	3 (2–6)	NA	NA
Length of stay, days, median (IQR)
In hospital	4 (2–6)	3 (2–5)	0.06	3 (2–5)	4 (2–7)	0.12
In ICU	3.5 (2.5–17)	2 (1.5–5)	0.08	3 (2–8)	2 (1–5)	0.24
Antiviral therapy, n (%)	11 (19)	97 (82)	<0.01	108 (61)	16 (8)	<0.01

Bold values are significantly different as defined by a p value <0.05.

ICU, intensive care unit; pH1N1, pandemic H1N1.