[1] Kenyatta Natl Hosp, Nairobi, Kenya
[2] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA
[3] Univ Washington, Dept Global Hlth, 325 Ninth Ave,Box 359909, Seattle, WA 98104 USA
[4] Univ Washington, Child Family & Populat Hlth, Seattle, WA 98195 USA
[5] Univ Washington, Dept Med, Seattle, WA USA
[6] Univ Washington, Dept Pediat, Seattle, WA 98195 USA
[7] Univ Washington, Dept Biobehav Nursing & Hlth Informat, Seattle, WA 98195 USA