1. Cochrane South Africa, South African Medical Research Council, Francie van Zijl Drive, Parrowvallei, 7505 Tygerberg, Cape Town, South Africa
2. Division of Epidemiology and Biostatistics, Department of Global Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Francie van Zijl Drive, Parrowvallei, 7505 Tygerberg, Cape Town, South Africa
3. Department of Community Medicine, Bayero University College of Health Sciences/Aminu Kano Teaching Hospital, PMB 3011, Along Zaria Road, Kano State, Nigeria
4. Warwick Centre for Applied Health Research and Delivery (WCAHRD), Division of Health Sciences, University of Warwick Medical School, CV4 7HL, UK
5. Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, 7925 Observatory, Cape Town, South Africa