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Table 2 Risk factors for SARS-CoV-2 seroconversion

From: Healthcare institutions’ recommendation regarding the use of FFP-2 masks and SARS-CoV-2 seropositivity among healthcare workers: a multicenter longitudinal cohort study

 

Baseline n = 2794

Follow up n = 2227

n total

n sero-conversion

% sero-conversion

OR

95% CI

p value

n total

N sero-conversion

% Sero-conversion

OR

95% CI

p value

Age

            

Per 10 years

2794

99

 

1.10

0.93–1.29

0.267

2227

290

 

0.99

0.98–1.00

0.104

Sex

            

Female

2197

76

3.5

   

1763

227

12.9

   

Male

597

23

3.9

1.12

0.68–1.77

0.645

464

63

13.6

1.06

0.78–1.43

0.689

Blood group

            

0

722

25

3.5

   

695

74

10.6

   

A

693

32

4.6

1.35

0.79–2.32

0.271

654

107

16.4

1.64

1.20–2.26

0.002

B

182

7

3.8

1.12

0.44–2.49

0.802

173

23

13.3

1.29

0.77–2.09

0.324

AB

64

0

0.0

0.00

0.00–15.72

0.977

64

14

21.9

2.35

1.20–4.35

0.009

unknown

1133

35

3.1

0.89

0.53–1.51

0.658

641

72

11.2

1.06

0.75–1.50

0.732

Employment rate

            

< 60%

514

15

2.9

   

410

61

14.9

   

60–79%

359

14

3.9

1.35

0.64–2.85

0.427

293

38

13.0

0.85

0.55–1.31

0.473

80–100%

1873

69

3.7

1.27

0.74–2.33

0.405

1436

182

12.7

0.83

0.61–1.14

0.245

Profession

            

Employee without patient exposure

559

11

2.0

   

478

48

10.0

   

Physician

376

9

2.4

1.22

0.49–2.98

0.660

273

28

10.3

1.02

0.62–1.66

0.925

Nurse

1118

51

4.6

2.38

1.28–4.85

0.010

886

143

16.1

1.72

1.23–2.46

0.002

Other employee with patient exposure

741

28

3.8

1.96

0.99–4.14

0.063

590

71

12.0

1.23

0.83–1.81

0.304

Type of patient exposure

            

None

845

18

2.1

   

709

74

10.4

   

No COVID-19 patients

1211

34

2.8

1.33

0.75–2.41

0.337

493

50

10.1

0.97

0.66–1.41

0.869

With COVID-19 patients

701

46

6.6

3.23

1.89–5.76

< 0.001

937

157

16.8

1.73

1.29–2.33

< 0.001

Unprotected exposure to COVID-19 patient

            

No

664

42

6.3

   

880

149

16.9

   

Yes

38

4

10.5

1.74

0.50–4.63

0.315

58

9

15.5

0.90

0.40–1.79

0.780

ICU employee

            

No

1675

67

4.0

   

1219

177

14.5

   

Yes

253

14

5.5

1.41

0.75–2.47

0.259

213

30

14.1

0.97

0.63–1.45

0.868

Employee at COVID-19 ward

            

No

1681

52

3.1

   

1151

148

12.9

   

Yes

246

29

11.8

4.19

2.57–6.69

< 0.001

281

59

21.0

1.80

1.28–2.51

0.001

Employee in emergency unit

            

No

1531

57

3.7

   

1114

166

14.9

   

Yes

396

24

6.1

1.67

1.00–2.69

0.041

318

41

12.9

0.85

0.58–1.21

0.37

Exposure to SARS-CoV2 infected co-worker

            

No

2368

58

2.4

   

1665

200

12.0

   

Yes

383

40

10.4

4.64

3.04–7.04

< 0.001

445

73

16.4

1.44

1.07–1.92

0.015

Non-occupational exposure to SARS-CoV2 infected person

            

No or unknown

2660

83

3.1

   

1810

166

9.2

   

Household

30

12

40.0

20.70

9.43–43.99

< 0.001

172

82

47.7

9.02

6.43–12.67

< 0.001

Outside household

61

3

4.9

1.61

0.39–4.46

0.432

157

33

21.0

2.64

1.72–3.95

< 0.001

Child (ren)living same in household

            

No

2081

73

3.5

   

1635

209

12.8

   

Yes

669

25

3.7

1.07

0.66–1.67

0.781

504

72

14.3

1.14

0.85–1.51

0.383

Regional incidence*

            

Low

2393

79

3.3

   

1879

219

11.7

   

Medium

141

1

0.7

0.16

0.01–1.94

0.151

129

23

17.8

1.68

0.78–3.61

0.184

High

260

19

7.3

1.88

0.50–7.12

0.353

219

48

21.9

2.06

1.10–3.89

0.025

FFP2 mask policy*

            

Specific use

1993

68

3.4

   

1636

204

12.5

   

General use

801

31

3.9

0.70

0.20–2.40

0.567

591

86

14.6

1.14

0.60–2.16

0.693

  1. Participants who seroconverted before the baseline assessment (n = 99) were excluded for analysis of seroconversion at follow-up. Note that total n for individual risk factors may be smaller due to missing values
  2. *For these factors determined at institutional level regression models included health care institutions as random effect