1. Department of
Medicine, Division of Pulmonary & Critical Care Medicine
2. Department of Medicine, Division of General Medicine
3. Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, California
4. Department of Medicine, Department of Medicine, Division of Infectious Diseases, Harvard Medical School, Boston, Massachusetts, USA
5. Department of Internal Medicine, University of KwaZulu-Natal, Durban, South Africa