1. Health Economics and Epidemiology Research Office, Faculty of Health Sciences, Department of Internal Medicine, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, South Africa
2. Department of Global Health, Boston University School of Public Health, Boston, MA, USA
3. Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
4. Right to Care, Johannesburg, South Africa
5. Clinical HIV Research Unit, Faculty of Health Sciences, Department of Internal Medicine, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, South Africa