1. Department of Family Medicine and Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA
2. Graduate School of Public Health, Department of Behavioral and Community Health Services, University of Pittsburgh, Pittsburgh, PA
3. Providence Hospital, Division of Infectious Diseases, Washington, DC
4. Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD
5. The Chicago MACS and the Ogburn-Stouffer Center for Social Organization Research at the National Opinion Research Center (NORC) University of Chicago, Chicago, IL
6. Department of Medicine, Division of Infectious Diseases, Georgetown University Medical Center, Washington, DC, USA