Xi'an Jiaotong University (XJTU) - China-Australia Joint Research Center for Infectious Diseases, The University of Hong Kong - Department of Family Medicine and Primary Care, Xi'an Jiaotong University (XJTU) - China-Australia Joint Research Centre for Infectious Diseases, The University of Hong Kong - Department of Family Medicine and Primary Care, Alfred Health - Melbourne Sexual Health Centre, World Health Organization (WHO), Xi'an Jiaotong University (XJTU) - Department of Infectious Diseases, The University of Hong Kong - Queen Mary Hospital, Xi'an Jiaotong University (XJTU) - China-Australia Joint Research Center for Infectious Diseases, The University of Hong Kong - Queen Mary Hospital and Alfred Health - Melbourne Sexual Health Centre