1. Liverpool School of Tropical Medicine; Department of Clinical Sciences; Pembroke Place Liverpool UK L3 5QA
2. Stellenbosch University; Division of Epidemiology and Biostatistics, Department of Global Health, Faculty of Medicine and Health Sciences; Cape Town South Africa
3. Stellenbosch University; Centre for Evidence Based Health Care, Division of Epidemiology and Biostatistics, Department of Global Health, Faculty of Medicine and Health Sciences; Francie van Zyl Drive, Tygerberg, 7505, Parow Cape Town Western Cape South Africa 7505
4. University of Cape Town; Desmond Tutu HIV Centre; Cape Town South Africa
5. University of Cape Town; Division of Clinical Pharmacology; Groote Schuur Hospital Observatory Cape Town South Africa 7925
6. Academic Medical Center, University of Amsterdam; Department of Clinical Epidemiology, Biostatistics and Bioinformatics; P.O. Box 22700 Amsterdam Netherlands 1100 DE
7. World Health Organization; Department of HIV & Global Hepatitis Programme; Geneva Switzerland