1 Kenyatta National Hospital, Nairobi 20723-00202, Kenya; Department of Global Health, University of Washington, Seattle, WA, USA. Electronic address: irenen@uw.edu.
2 Department of Global Health, University of Washington, Seattle, WA, USA; Department of Epidemiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA; Department of Medicine, University of Washington, Seattle, WA, USA.