1. Department of Global Health, University of Washington, Seattle, WA, USA
2. Kenyatta National Hospital, Research and Programs, Nairobi, Kenya
3. Department of Epidemiology, University of Washington, Seattle, WA, USA
4. Kenya Medical Research Institute, Kisumu, Kenya
5. Department of Pediatrics and Child Health, University of Nairobi, Nairobi, Kenya
6. Department of Medicine, University of Washington, Seattle, WA, USA
7. Department of Pediatrics, University of Washington, Seattle, WA, USA