1. Department of Epidemiology; Harvard School of Public Health; Boston MA
2. Department of Biostatistics; Harvard School of Public Health; Boston MA
3. The Connors Center for Women's Health and Gender Biology; Brigham and Women's Hospital; Boston MA
4. Department of Nutrition; Harvard School of Public Health; Boston MA
5. Department of Pediatrics and Child Health; Muhimbili University of Health and Allied Sciences; Dar es Salaam Tanzania
6. Department of Microbiology and Immunology; Muhimbili University of Health and Allied Sciences; Dar es Salaam Tanzania
7. Department of Global Health and Population; Harvard School of Public Health; Boston MA