1. Department of Medicine, University of Alabama at Birmingham, Birmingham, USA
2. Departments of Medicine, Pediatrics, and Microbiology and Immunology, New York-Presbyterian Hospital -Weill Cornell Medical Center, New York, USA
3. Department of Medicine, Duke University School of Medicine, Durham, USA
4. Department of Medicine, The University of Texas MD Anderson Cancer Center, Houston, USA
5. Departments of Medicine, Pathology, and Epidemiology, The Johns Hopkins Hospital, Baltimore, USA
6. Department of Medicine, Mayo Clinic, Rochester, USA
7. Department of Medicine, University of Texas Health Science Center and South Texas Veterans Health Care System, San Antonio, USA
8. Department of Medicine, University of Pennsylvania Medical Center, Philadelphia, USA
9. Department of Medicine, Emory University School of Medicine, Atlanta, USA
10. Department of Medicine, University of Florida, Gainesville, USA
11. Department of Medicine, University of Wisconsin, Madison, USA
12. Centers for Disease Control and Prevention, Atlanta, USA