1. Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
2. Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
3. Department of Health Behavior, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
4. Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN, USA
5. Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, OH, USA
6. Center for Research and Training on HIV/AIDS, Hanoi Medical University, Hanoi, Vietnam