1. Centre for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
2. Health Economics and Epidemiology Research OfficeDepartment of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
3. Division of Epidemiology and BiostatisticsSchool of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
4. Centre for Actuarial Research, University of Cape Town, Cape Town, South Africa
5. Desmond Tutu HIV Centre, University of Cape Town, Cape Town, South Africa
6. Center for Global Health and DevelopmentBoston University, Boston, MA, USA