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Volume 28, Number 10—October 2022

Nosocomial COVID-19 Incidence and Secondary Attack Rates among Patients of Tertiary Care Center, Zurich, Switzerland

Aline WolfensbergerComments to Author , Verena Kufner, Maryam Zaheri, Marius Zeeb, Isabelle Nortes, Peter W. Schreiber, Miriam Vazquez, Verena Schärer, Thomas Scheier, Stefan Schmutz, Elisabeth Probst, Dirk Saleschus, Michael Huber, Silvana K. Rampini, and Walter Zingg
Author affiliations: University Hospital Zürich and University of Zürich Division of Infectious Diseases and Hospital Epidemiology, Zurich, Switzerland (A. Wolfensberger, M. Zeeb, P.W. Schreiber, M. Vazquez, V. Schärer, T. Scheier, D. Saleschus, W. Zingg); University of Zürich Institute of Medical Virology, Zurich (V. Kufner, M. Zaheri, M. Zeeb, S. Schmutz, M. Huber); University Hospital Zürich and University of Zürich Department for Internal Medicine, Zurich (I. Nortes, S.K. Rampini); University Hospital Zürich Clinic of Immunology, Zurich (E. Probst)

Main Article


Univariable and multivariable analysis of factors associated with SARS-CoV-2 transmission to exposed patients in a hospital in Zurich, Switzerland, October 2020–June 2021*

Exposure Exposed patients positive for SARS-CoV-2, n = 42 Exposed patients not positive for SARS-CoV-2, n = 256 OR (95%CI)
Univariable analysis Multivariable analysis
Contact time of index and exposed patient in hours, median (IQR) 54 (28–96) 17 (8–29) 1.03 (1.02–1.03) 1.02 (1.01–1.03)
Ct value of index patient in units, median (IQR) 19 (18–26) 28 (19–33) 0.91 (0.87–0.96) 0.93 (0.87–0.98)
AGP in index patient, mean (SD) 0.26 (0.44) 0.25 (0.43) 1.04 (0.50–2.19) NA
Exposure on IMC/ICU, mean (SD) 0.14 (0.35) 0.31 (0.46) 0.37 (0.15–0.92) 0.70 (0.27–1.87)
Male sex of index patient, mean (SD) 0.55 (0.50) 0.52 (0.50) 1.08 (0.56–2.09) NA
Age of index patient, y, median (IQR) 71 (58–77) 72 (58–78) 1.00 (0.98–1.02 NA
Exposure before mandatory patient masking at bed place, mean (SD) 0.09 (0.28) 0.11 (0.32) 1.41 (0.50–3.96 NA
Calendar week into second and third waves, median (IQR) 13 (9–17) 13 (8–18) 0.96 (0.91–1.01) 0.95 (0.90–1.01)

*AGP, aerosol-generating procedures; Ct, cycle threshold; IQR, interquartile range; IMC, intermediate care units; ICU, intensive care units; NA, not available; OR, odds ratio.

Main Article

Page created: July 31, 2022
Page updated: September 21, 2022
Page reviewed: September 21, 2022
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