1. Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, Maryland , United States
2. Rakai Health Sciences Program , Entebbe , Uganda
3. Department of Pathology, School of Medicine, Johns Hopkins University , Baltimore, Maryland , United States
4. Division of Infectious Diseases, School of Medicine, Johns Hopkins University , Baltimore, Maryland , United States
5. Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda, Maryland , United States