1. Department of Medicine, Division of Pulmonology and Critical Care, Johannesburg Hospital and University of the Witwatersrand,
2. Division of Clinical Microbiology and Infectious Disease of the National Health Laboratory Service and University of the Witwatersrand
3. School of Statistics and Actuarial Science, University of the Witwatersrand Johannesburg, South Africa
4. Department of Medicine, Division of Pulmonology and Critical Care, Johannesburg Hospital and University of the Witwatersrand