1. Department of Health Sciences; University of York; York UK
2. Centre for Research in Health and Development; York UK
3. Usher Institute; University of Edinburgh; Edinburgh UK
4. Institute for Global Health; University College London; London UK
5. Sigma Research, Department of Public Health, Environments & Society; London School of Hygiene and Tropical Medicine; London UK
6. Hull York Medical School; University of York; York UK
7. Department of Community and Family Medicine, School of Public Health; The University of Zambia; Lusaka Zambia
8. Nuffield Department of Primary Care Health Sciences; University of Oxford; Oxford UK