1. Department of Family Medicine and Community Health, School of Medicine, Duke University, Durham, North Carolina.
2. UNC Project Lilongwe, Lilongwe, Malawi.
3. FHI 360, Lilongwe, Malawi.
4. Department of Epidemiology, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
5. Division of Infectious Diseases, University of North Carolina at Chapel Hill.
6. Department of Population Health Sciences, School of Medicine, Duke University, and the Duke Clinical Research Institute, Duke University.