1 Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
2 Department of Public Health, Travel Medicine and Infectious Diseases, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
3 Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Department of Public Health, Travel Medicine and Infectious Diseases, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland. Electronic address: [email protected].