1. Center for Hematology and Oncology, University Hospital Zurich, Switzerland;
2. Department of Biostatistics at Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland;
3. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Switzerland;
4. Medical Oncology and Hematology, Triemli City Hospital, Switzerland;
5. Division of Gastroenterology and Hepatology, University Hospital Zurich, Switzerland;
6. Division of Hematology, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland