1. Department I of Internal Medicine, University Hospital of Cologne, Germany
2. German Center for Infection Research (DZIF), partner site Bonn-Cologne, Germany
3. Division of Infectious Diseases, University of California San Diego
4. Division of Pulmonology and Section of Infectious Diseases, Medical University of Graz, Austria
5. Institute of Virology, University of Bonn Medical Center, Germany
6. Department for Internal Medicine I, University Hospital of Bonn, Germany
7. Institute of Virology, University Hospital of Cologne, Germany
8. Department of Medicine, San Diego VA Medical Center, California