1. National University of Science and Technology (NUST) Faculty of Medicine, NUST Complex Mpilo Hospital , Vera Road, Mzilikazi, PO Box 2096, Bulawayo , Zimbabwe
2. Imperial Clinical Trials Unit, Imperial College London , Stadium House, 68 Wood Lane, London W12 7RH , UK
3. Department of Primary Care and Public Health, Imperial College London , St Dunstan’s Road, London W6 8RP , UK
4. Faculty of Applied Sciences, Department of Statistics, National University of Science and Technology (NUST) , PO Box AC 939, Ascot, Bulawayo , Zimbabwe
5. Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Zimbabwe , PO Box MP 167, Mount Pleasant, Harare , Zimbabwe