1. Head of Epidemiology, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand </br> 2. Associate Professor, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, OX3 7FZ, UK </br> 3. Visiting Scientist, Harvard TH Chan School of Public Health, Harvard University, Boston, MA 02115, USA