1. Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
2. Department of Sociology, Duke University, Durham, North Carolina, USA
3. Microsoft Research, Redmond, Washington, USA
4. London School of Hygiene and Tropical Medicine, London, United Kingdom
5. Division of Public Health, North Carolina Department of Health and Human Services, Raleigh, North Carolina, USA
6. Section of Infectious Diseases, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
7. Division of Sexually Transmitted Disease (STD) Prevention, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA