1. Boston University Center for Global Health and Development, Boston University, Boston, MA 02118, USA
2. Department of International Health, Boston University School of Public Health, Boston University, Boston, MA 02118, USA
3. Health Economics and Epidemiology Research Office, Department of Clinical Medicine, School of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2198, South Africa
4. Right to Care, Johannesburg 2041, South Africa
5. United States Agency for International Development, South Africa Mission, Pretoria 0027, South Africa
6. Department of Epidemiology, Boston University School of Public Health, Boston University, Boston, MA 02118, USA