1. Swiss Tropical and Public Health Institute Basel, University of Basel, Socinstrasse 57, Basel, Switzerland
2. Epidemiology, Biostatistics and Prevention Institute, University of Zürich, Hirschengraben 84, Zürich, Switzerland
3. Department of Rheumatology, Basel University Hospital, Petersgraben 4, Basel, Switzerland
4. Division for Infectious Diseases and Hospital Epidemiology, Basel University Hospital, Petersgraben 4, Basel, Switzerland