Table 1.

Study subjects and incidence of hospital-acquired respiratory virus infection

Variable	Admissions	Conduction of respiratory virus PCR	Positive PCR	Incidence (95% CI) of HA-RV infection per 1,000 admissions	Incidence (95% CI) of HA-RV infection per 10,000 patients days
Total	453,075	21,288	1,770	3.9(3.7-4.1)	4.9(4.7-5.2)
Year
2012	110,929	4,751	418	3.8(3.4-4.1)	4.6(4.2-5.1)
2013	111,128	4,536	404	3.6(3.3-4.0)	4.5(4.1-5.0)
2014	114,023	5,429	440	3.9(3.5-4.2)	4.9(4.5-5.4)
2015	116,995	6,572	508	4.3(4.0-4.7)	5.7(5.2-6.2)
Sex
Male	231,174	12,573	1,028	4.5(4.2-4.7)	5.2(4.9-5.5)
Female	221,901	8,715	742	3.3(3.1-3.6)	4.6(4.3-4.9)
Age group
≤15 y	47,167	3,474	455	9.7(8.8-10.5)	12.9(11.7-14.1)
>15 y	405,908	17,814	1,315	3.2(3.1-3.4)	4.1(3.8-4.3)
Ward
Medical ward	297,746	14,071	1,253	4.2(4.0-4.4)	5.5(5.2-5.9)
Surgical ward	139,461	2,737	266	1.9(1.7-2.1)	2.5(2.2-2.8)
Intensive care unit	15,868	4,480	251	15.8(13.9-17.8)	9.8(8.6-11.0)
Virus*
Rhinovirus				1.26(1.16-1.37)	1.60(1.47-1.73)
Influenza virus				0.73(0.66-0.81)	0.93(0.83-1.03)
Influenza A				0.56(0.49-0.63)	0.71(0.62-0.80)
Influenza B				0.17(0.14-0.21)	0.22(0.17-0.27)
Parainfluenza virus				0.65(0.57-0.72)	0.82(0.73-0.91)
Respiratory syncytial virus				0.53(0.46-0.60)	0.67(0.58-0.75)
Human coronavirus OC43/HKU-1 or 229E/NL63				0.51(0.44-0.57)	0.64(0.56-0.72)
Human metapneumovirus				0.20(0.16-0.24)	0.25(0.20-0.31)
Bocavirus				0.12(0.09-0.15)	0.15(0.11-0.19)
Adenovirus				0.09(0.07-0.12)	0.12(0.08-0.16)
Enterovirus				0.07(0.04-0.09)	0.08(0.05-0.11)

CI, confidence interval; HA-RV, hospital-acquired respiratory virus; PCR, polymerase chain reaction.

^*Some patients had ≥2 viruses. The maximum incubation period was defined as follows: rhinovirus(3 days), influenza virus(4 days), parainfluenza virus(6 days), respiratory syncytial virus(8 days), human coronavirus(5 days), human metapneumovirus(5 days), bocavirus(4 days), adenovirus(14 days), and enterovirus(6 days).