1. Anova Health Institute, Parktown, Johannesburg, South Africa
2. Department of Global Health, Boston University School of Public Health, Boston, MA, USA
3. Health Economics and Epidemiology Research Office, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg
4. Southern Africa Labour and Development Research Unit, University of Cape Town, Cape Town, South Africa
5. Department of Family and Community Health, School of Nursing, University of Pennsylvania
6. Department of Medical Ethics and Health Policy, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
7. Department of Community Health, School of Public Health, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa.