1. Department of Haematology, National Health Laboratory Service Tygerberg Hospital Cape Town South Africa
2. Faculty of Medicine and Health Sciences University of Stellenbosch Cape Town South Africa
3. Department of Medical Microbiology and Immunology National Health Laboratory Service Johannesburg South Africa
4. Division of Paediatric Rheumatology and Immunology, Department of Paediatrics and Child Health Tygerberg Hospital Cape Town South Africa
5. Division of Epidemiology and Biostatistics, Department of Global Health University of Stellenbosch Cape Town South Africa