1. Health Economics Research Unit, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
2. Health Policy and Systems Division, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
3. Department of Global Health and Development, Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
4. Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
5. Health Systems Research Group, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya