1. Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC;
2. UNC Project Malawi, Lilongwe, Malawi;
3. RTI International, Research Triangle Park, NC;
4. Partners in Hope, Lilongwe, Malawi;
5. Institute of Global Health and Infectious Disease, University of North Carolina at Chapel Hill, Chapel Hill, NC; and
6. Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, OH.