1. Medical Practice Evaluation Center, Department of Medicine, Massachusetts General Hospital, Boston, United States of America.
2. jpinkney@mgh.harvard.edu
3. University of the West Indies, Mona, Jamaica.
4. Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, United States of America.
5. RAND Corporation, Santa Monica, United States of America.
6. Boston Public Health Commission, Boston, United States of America.