1. Anova Health Institute, Johannesburg, South Africa.
2. Department of Environmental and Geographical Sciences, University of Cape Town, Cape Town, South Africa.
3. Independent Researcher, Cambridge, United Kingdom.
4. School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa.
5. Division of Infectious Diseases and HIV Medicine, Department of Medicine, University of Cape Town, Cape Town, South Africa.