1. Medical Practice Evaluation Center, Massachusetts General Hospital, Boston, Massachusetts, USA.
2. Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts, USA.
3. Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA.
4. Harvard Medical School, Department of Medicine, Boston, Massachusetts, USA.
5. Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
6. Massachusetts Department of Public Health, Boston, Massachusetts, USA.