City University of Macau, City University of Macau, City University of Macau, National University of Singapore (NUS) - Duke-NUS Medical School, Boston University, Zhuhai Center for Disease Control and Prevention, Sun Yat-sen University (SYSU), Nanjing Medical University, Jinan University, Alfred Health - Melbourne Sexual Health Centre, The University of Hong Kong - Department of Family Medicine and Primary Care, The University of Hong Kong, University of North Carolina Project-China and University of Oxford - Nuffield Department of Medicine