1. South African Medical Research Council, Burden of Disease Research Unit, Cape Town, South Africa
2. University of KwaZulu-Natal, College of Health Sciences, School of Nursing and Public Health, Durban, South Africa
3. South African Medical Research Council, HIV Prevention Research Unit, Durban, South Africa
4. International Health Transitions, Canberra, Australia
5. The University of Sydney, School of Public Health, Sydney, Australia