1. Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, MA
2. Department of Pediatrics and Child Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
3. Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
4. Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA
5. Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA
6. Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA
7. Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA