1. a South African Research Chairs Initiative (SARChI), PTSD program, Department of Psychiatry , University of Stellenbosch , Cape Town , South Africa
2. b MRC Unit on Anxiety and Stress Disorders , University of Stellenbosch , Cape Town , South Africa
3. c Department of Statistics and Actuarial Sciences, Centre for Statistical Consultation , University of Stellenbosch , Cape Town , South Africa
4. d Department of Epidemiology, Mailman School of Public Health , Columbia University , New York , USA
5. e Infectious Diseases Epidemiology Unit, School of Public Health & Medicine , University of Cape Town , Cape Town , South Africa
6. f Department of Psychiatry , University of Cape Town , Cape Town , South Africa