1. MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
2. Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK
3. University of Agder, Kristiansand, Norway
4. Institute for Global Health, Faculty of Population Health, University College London, London, UK
5. Institute for Risk and Disaster Reduction, Faculty of Mathematical and Physical Sciences, University College London, London, UK
6. Mrc Unit the Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia