1. Botswana Harvard AIDS Institute Partnership, Gaborone , Botswana
2. Faculty of Health Sciences, Medical Laboratory Sciences, University of Botswana, Gaborone , Botswana
3. Faculty of Science, Biological Sciences, University of Botswana, Gaborone , Botswana
4. Department of Immunology and Infectious Diseases, Harvard University T.H. Chan School of Public Health, Boston, MA , USA
5. Division of Infectious Disease, Brigham and Women's Hospital, Boston, MA , USA