1. 1Vanderbilt Institute for Global Health, Vanderbilt University Medical Center, Nashville, Tennessee;
2. 2Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee;
3. 3Yale School of Public Health, Yale University, New Haven, Connecticut;
4. 4Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee;
5. 5Department of Health Policy, Vanderbilt University Medical Center, Nashville, Tennessee