1. Department of Global Health, University of Washington, Seattle, Washington, USA.
2. Department of Research and Programs, Kenyatta National Hospital, Nairobi, Kenya.
3. Department of Epidemiology, University of Washington, Seattle, Washington, USA.
4. Department of Pediatrics and Child Health, University of Nairobi, Nairobi, Kenya.
5. United Nations International Emergency Children's Fund, Department of Maternal and Newborn Health.
6. Department of Biostatistics, University of Washington, Seattle, Washington, USA.
7. Department of Medicine, University of Washington, Seattle, Washington, USA.
8. Department of Pediatrics, University of Washington, Seattle, Washington, USA.