1. Health Economics Unit, University of Cape Town, Cape Town, South Africa
2. School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
3. Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
4. Health Policy Research Group, Department of Pharmacology and Therapeutics, University of Nigeria, Nsukka, Nigeria
5. Department of Economics, University of Nigeria, Nsukka, Nigeria
6. Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK