1 Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Department of Disease Control, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK; Heidelberg Institute of Global Health, University of Heidelberg, Germany. Electronic address: anneliesws@gmail.com.
2 Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore.