Capital Medical University - Clinical and Research Center for Infectious Diseases, Government of the People's Republic of China - Beijing Hospital, Capital Medical University - Clinical and Research Center for Infectious Diseases, Rainbow Clinic of Beijing Jingcheng Skin Diseases Hospital, Tianjin Centers for Disease Control and Prevention - Department of AIDS/STD Control and Prevention, AIDS Healthcare Foundation (AHF), Beijing, Capital Medical University - Clinical and Research Center for Infectious Diseases, University of Tennessee, Knoxville - Department of Public Health, East Tennessee State University - Department of Biostatistics and Epidemiology, The Education University of Hong Kong - Department of Health and Physical Education, University of North Carolina Project-China, Chinese Academy of Medical Sciences - National Center for Clinical Laboratories, Capital Medical University - Clinical and Research Center for Infectious Diseases, The Chinese University of Hong Kong (CUHK) - Centre for Health Behaviours Research and Peking University - Clinical Research Academy