1. Cochrane South Africa, South African Medical Research Council, Francie van Zijl Drive, Parrow Valley, Cape Town 7500, South Africa
2. Division of Epidemiology and Biostatistics, Department of Global Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Francie van Zijl Drive, Tygerberg, Cape Town 7505, South Africa
3. Department of Community Medicine, Faculty of Clinical Sciences, Bayero University Kano, inside Aminu Kano Teaching Hospital, along Zaria Road, Kano 700233, Nigeria
4. Communicable and Non-Communicable Diseases Cluster, World Health Organization Regional Office for Africa, Djoue, Brazzaville BP 06, Congo