1. Faculty of Medicine, Imperial College London, UK
2. Médecins Sans Frontières, Cape Town, South Africa; Centre for Infectious Disease Epidemiology and Research, University of Cape Town, South Africa
3. Manson Unit, Médecins Sans Frontières, London, UK
4. Faculty of Medicine, Imperial College London, UK; Africa Centre for Health and Population Studies, University of KwaZulu-Natal, South Africa
5. Centre for Infectious Disease Epidemiology and Research, University of Cape Town, South Africa; Manson Unit, Médecins Sans Frontières, London, UK