1. Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
2. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
3. Division of Infectious Diseases, Geneva University Hospital, University of Geneva, Geneva, Switzerland
4. Division of Infectious Diseases, University Hospital of Lausanne, University of Lausanne, Lausanne, Switzerland
5. Institute of Medical Virology, University of Zurich, Zurich, Switzerland
6. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, University of Basel, Basel, Switzerland
7. Division of Infectious Diseases, Regional Hospital of Lugano, Lugano, Switzerland
8. Division of Infectious Diseases, Cantonal Hospital of St Gallen, St Gallen, Switzerland
9. Division of Infectious Diseases, Cantonal Hospital of Aarau, Aarau, Switzerland
10. Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland