Table 1 Characteristics of the controls and patients with laboratory-confirmed, hospital-acquired influenza (HAI) and of the factors associated with HAI in Edouard Herriot Hospital, Lyon (France), in influenza seasons 2004-05, 2005-06 and 2006-07

Gender, female

8 (73)

33 (75)

1.0

0.89 (0.22-3.72)

Age, years

0.99 (0.97-1.02)^b

   Median (range)

66.0 (48.5-85.1)

78.7 (42.3-86.7)

0.6

Type of ward

1.0

   Medicine

8 (73)

31 (70)

1.0 (Ref.)

   Surgery

3 (27)

13 (30)

0.90 (0.21-3.89)

Chronic pulmonary disease

2 (18)

5 (11)

0.6

1.60 (0.31-8.25)

Chronic cardiac disease

5 (45)

21 (48)

1.0

0.92 (0.26-3.28)

Immuno-depression

2 (18)

1 (2)

0.10

8.00 (0.73-88.22)

Potential influenza source in the unit^c

7 (64)

13 (30)

0.08

4.06 (1.08-15.33)

Individual influenza vaccination^{d, e}

2 (20)

21 (48)

0.16

0.34 (0.069-1.70)

Proportion of vaccinated HCW in the unit

0.10

   < 35%

8 (73)

19 (43)

1.0 (Ref.)

   ≥ 35%

3 (27)

25 (57)

0.16 (0.018-1.32)