1. National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
2. Department of Epidemiology, University of California, Los Angeles (UCLA) Fielding School of Public Health
3. Tsinghua University, Beijing, China
4. Department of Biostatistics, UCLA Fielding School of Public Health, Los Angeles, California
5. British Columbia Center for Excellence in HIV/AIDS, University of British Columbia, Vancouver, Canada