Table 2

Association between quarantine, symptoms contact with patients with COVID-19, and prophylaxis and prevalence of positive tests (anti-SARS-CoV-2 IgG ≥15 AU/mL) among healthcare workers in a large university hospital, Milan, Italy, 27 April 2020 to 12 June 2020

VariableWorkersPositive test
NN%P value*OR†95% CI†
Quarantine
 No36291433.9<0.0011.00Reference
 Yes42616639.015.612.0 to 20.1
Any symptom
 No2544843.3<0.0011.00Reference
 Yes151122514.95.123.95 to 6.64
Number of symptoms
 1608569.2<0.0012.972.09 to 4.22
 23894511.63.832.62 to 5.60
 32263816.85.913.93 to 8.93
 411182420.37.484.54 to 12.3
 5–101706236.516.811.5 to 24.6
Contact with COVID-19 case
 Unknown23721345.6<0.0011.00Reference
 Suspected case3353410.11.891.27 to 2.80
 Confirmed case119012010.11.871.45 to 2.42
 Missing1582113.3
 Among suspected or confirmed, contact with
 Patients or colleagues within the hospital888788.8<0.0011.00Reference
 Family member941920.22.601.49 to 4.52
 Missing5435710.5
Prophylaxis or therapy
 No39192656.8<0.0011.00Reference
 Yes1364432.36.594.51 to 9.65
Nasopharyngeal swab
 Negative*23761757.4<0.0011.00Reference
 Positive17413074.737.125.5 to 54.0
 Not performed150640.30.030.01 to 0.09
  • *From χ2 test. For number of symptoms: from χ2 test for trend. Missing data not included in analysis.

  • †From univariate logistic regression models. Missing data not included in analyses.