1. Department of Global Health, University of Washington, Seattle, Washington, USA
2. Department of Epidemiology, University of Washington, Seattle, Washington, USA
3. Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
4. Department of Paediatrics and Child Health, University of Nairobi, Nairobi, Kenya
5. Centers for Disease Control and Prevention, CDC-Kenya, Nairobi, Kenya
6. Department of Laboratory Medicine, 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