1. Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California.
2. Division of General Internal Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California.
3. Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
4. Division of Infectious Diseases, Department of Medicine, University of California, San Francisco, San Francisco, California.