1 Kenya Medical Research Institute, Nairobi 54840-00200, Kenya. Electronic address: fmogaka@kemri-ucsf.org.
2 Department of Global Health, University of Washington, Seattle, WA, USA; Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, WA, USA.
3 Kenya Medical Research Institute, Nairobi 54840-00200, Kenya; Department of Global Health, University of Washington, Seattle, WA, USA.