1. Department of Paediatrics & Child Health, Red Cross War Memorial Children's Hospital, and SA MRC Unit on Child & Adolescent Health, University of Cape Town, Cape Town, South Africa
2. Department of Pediatrics, Division of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
3. Division of Epidemiology & Biostatistics, School of Public Health & Family Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
4. SA MRC Unit on Risk & Resilience in Mental Disorders, Department of Psychiatry, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa