1. Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
2. The Health Research Unit Zimbabwe, Biomedical Research and Training Institute, Harare, Zimbabwe
3. MRC International Statistics and Epidemiology Group, Faculty of Epidemiology and Population Health
4. Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
5. Faculty of Medicine and Health Sciences, University of Zimbabwe, Harare, Zimbabwe
6. Musculoskeletal Research Unit, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.