1. Division of Infectious Diseases, Department of Medicine, Stanford University, Palo Alto, California.
2. Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, Maryland.
3. Division of Infectious Diseases, Department of Medicine, Northwestern University, Chicago, Illinois.
4. Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
5. Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland.
6. Division of Endocrinology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland.
7. Division of Infectious Diseases, Department of Medicine, University of Texas Health Science Center at Houston, Houston, Texas.