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Table 2 Univariate analysis of factors associated with transmission of SARS

From: Clinical and epidemiological predictors of transmission in Severe Acute Respiratory Syndrome (SARS)

  Patients with secondary transmission Patients with no secondary transmission    
  (n = 22) (n = 76)    
Factors n % n % OR 95%CI p-value
Demographics        
Age        
- < = 24 4 18.2% 19 25.0% 1.00 (Ref)
- 25 to 49 12 54.5% 49 64.5% 1.16 (0.33–4.06) 0.812
- 50 and above 6 27.3% 8 10.5% 3.56 (0.79–16.14) 0.099
Female gender (vs male) 19 86.4% 60 78.9% 1.69 (0.44–6.43) 0.442
Non-Chinese ethnicity (vs Chinese) 6 27.3% 34 44.7% 0.46 (0.16–1.31) 0.148
Epidemiological features        
Context of exposure to SARS        
- healthcare worker 7 31.8% 50 65.8% 1.00 (Ref)
- hospital inpatient 6 27.3% 4 5.3% 10.70 (2.41–47.6) 0.002
- *others 9 40.9% 22 28.9% 2.92 (0.97–8.85) 0.058
Date of onset        
- 21/3/03 or earlier (before universal PPE) 18 81.8% 60 78.9% 1.00 (Ref)
- 22/3//03 or later (after universal PPE) 4 18.2% 16 21.1% 1.61 (0.49–5.32) 0.437
Delayed isolation (on Day 7 or later) 16 72.7% 18 23.7% 8.59 (2.93–25.23) <0.001
Ever admitted to a non-isolation ward 11 50.0% 1 1.3% 75.00 (8.8–639.18) <0.001
Clinical features        
Chronic illness        
- chronic respiratory illness 5 22.7% 2 2.6% 10.88 (1.94–60.92) 0.007
- disease with immunosuppression 5 22.7% 5 6.6% 4.18 (1.09–16.08) 0.038
Disease severity at time of isolation        
- had an abnormal chest radiograph 15 68.2% 63 82.9% 0.44 (0.15–1.3) 0.138
- required oxygen therapy 7 31.8% 7 9.2% 4.60 (1.4–15.08) 0.012
- admitted to ICU or HD 4 18.2% 0 0.0% NC
- intubated 2 9.1% 0 0.0% NC
Signs and symptoms at time of isolation        
- temperature > = 38oC 16 72.7% 58 76.3% 0.83 (0.28–2.43) 0.731
- fever 21 95.5% 74 97.4% 0.57 (0.05–6.57) 0.65
- cough 13 59.1% 42 55.3% 1.17 (0.45–3.06) 0.75
- dyspnoea 9 40.9% 15 19.7% 2.82 (1.01–7.81) 0.047
- vomiting 8 36.4% 9 11.8% 4.25 (1.4–12.95) 0.011
- diarrhoea 6 27.3% 8 10.5% 3.19 (0.97–10.48) 0.056
^Laboratory investigations        
- alanine aminotransferase >41IU/L 7 31.8% 17 22.4% 1.62 (0.57–4.61) 0.367
- maximum lactate dehydrogenase >650IU/L 14 63.6% 10 13.2% 11.55 (3.87–34.49) <0.001
- minimum platelet count < = 184*10^9/L 8 36.4% 16 21.1% 2.14 (0.77–6) 0.147
- maximum neutrophil count >5.04*10^9/L 11 50.0% 13 17.1% 4.85 (1.74–13.53) 0.003
- minimum lymphocyte count < = 0.93*10^9/L 9 40.9% 15 19.7% 2.82 (1.01–7.81) 0.047
  1. *others: original imported index patient and hospital visitors
  2. ^unit of measurement as in Table 1