1. Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts.
2. Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
3. Botswana–Harvard School of Public Health AIDS Initiative Partnership, Gaborone, Botswana.
4. Harvard College, Faculty of Arts and Sciences, Harvard University, Cambridge, Massachusetts.
5. Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts.