1. Research Centre for Public Health, School of Medicine, Tsinghua University, Beijing, China
2. Melbourne Sexual Health Centre, Alfred Health, Melbourne, Australia
3. Central Clinical School, Faculty of Medicine, Monash University, Melbourne, Australia
4. London School of Hygiene and Tropical Medicine, London, UK
5. Section of Epidemiology and Biostatistics, School of Population Health, The University of Auckland, Auckland, New Zealand
6. School of Public Health and Preventive Medicine, Faculty of Medicine, Monash University, Melbourne, Australia