Table 1 Comparison of the main clinical and virological features of index and contact patients between the on-site isolation and control group

Age (years), median (IQR)

73.0 (63.5-77.0)

73.5 (63.0-79.5)

0.41

71 (57.0-78.0)

70 (60.5-76)

0.61

Male, n (%)

17 (81.0)

19 (59.4)

0.10

21 (77.8)

40 (61.5)

0.13

Comorbidities, n (%)

 Chronic lung disease

4 (19.0)

5 (15.6)

0.95

4 (14.8)

9 (13.8)

0.79

 Diabetes

6 (28.6)

9 (28.1)

0.88

8 (29.6)

12 (18.5)

0.42

 Hypertension

16 (76.2)

23 (71.9)

0.35

15 (55.6)

38 (58.5)

0.52

 Chronic cardiovascular disease

5 (23.8)

16 (50.0)

0.03

13 (48.1)

21 (32.3)

0.25

 Chronic renal disease

4 (19.0)

7 (21.9)

0.74

6 (22.2)

6 (9.2)

0.26

 Chronic liver disease

2 (9.5)

1 (3.1)

0.56

3 (11.1)

5 (7.7)

0.69

 Chronic neurological impairment/dementia

2 (9.5)

2 (6.3)

0.46

5 (18.5)

7 (10.8)

0.46

 Cancer

2 (9.5)

6 (18.8)

0.44

5 (18.5)

13 (20.0)

0.72

 HIV/ Immunosuppressive treatment

2 (9.5)

2 (6.3)

0.99

1 (3.7)

6 (9.2)

0.43

Length of stay* (days), median (IQR)

0 (0-1)

1 (0-5.75)

0.02

8 (4-11)

10 (4-20.5)

0.24

Ct-value, median (IQR)

30.5 (26.4 – 33.3)

22.8 (19.0-29.7)

0.005

-

-

-

Symptoms, n (%)

 Cough

11 (64.7)

11 (68.8)

0.81

-

-

-

 Dyspnea

8 (47.1)

2 (12.5)

0.04

-

-

-

 Fever

14 (82.4)

10 (62.5)

0.19

-

-

-

 Oxygen supplementation

13 (61.9)

11 (34.4)

0.05

-

-

-

Death, n (%)

0 (0.0)

5 (15.6)

0.14

-

-

-

Ward, n (%)

-

-

-

0.01

 Surgery

1 (3.7)

9 (13.8)

 Medicine

24 (88.9)

37 (56.9)

 ICU

2 (7.4)

19 (26.2)

Four-bed room, n (%)

-

-

-

14 (51.9)

31 (47.7)

0.72

Adjacent bed to index, n (%)

-

-

-

17 (63.0)

42 (64.6)

0.88

Duration of contact (hours), median (IQR)

-

-

-

11.5 (6.8-17.7)

20.4 (12.4-42.0)

<0.001

SARS-CoV-2 test performed, n (%)

-

-

-

9 (33.3)

41 (63.1)

0.01

SARS-CoV-2 positive, n (%)

After exclusion through WGS, n (%)

-

-

-

1 (3.7)

0 (0.0)

12 (18.5)

10 (15.9)^&

0.10

0.03