1. Health Economics and Epidemiology Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
2. Boston University, Center for Global Health & Development, Boston, MA, USA
3. Clinical HIV Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
4. Right to Care, Johannesburg, South Africa
5. Department of Medicine, University of California, San Diego, CA, USA