1. Health Systems Unit, South African Medical Research Council, Tygerberg, South Africa and Public Health Department, University of Cape Town,
South Africa
2. Public Health Department, University of Cape Town, South Africa
3. Health Systems Unit, South African Medical Research Council, Tygerberg, South Africa
4. Biostatistics Unit, South African Medical Research Council, South Africa
5. Health Sciences Faculty, New York University, USA
6. Health Services Research Unit, Norwegian National Institute of Public Health, Norway
7. Division of STD Prevention, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, USA