1. Section of Infectious Disease, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut;
2. Department of Internal Medicine, Edendale Hospital, University of KwaZulu-Natal, Pietermaritzburg, South Africa
3. Department of Epidemiology (Microbial Diseases), Yale University School of Public Health, New Haven, Connecticut;
4. Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut;