[1] Bill & Melinda Gates Fdn, Seattle, WA 98109 USA
[2] Univ N Carolina, Dept Epidemiol, Chapel Hill, NC 27515 USA
[3] Univ Washington, Dept Global Hlth, Seattle, WA 98195 USA
[4] Univ Witwatersrand, Fac Hlth Sci, Wits RHI, Johannesburg, South Africa
[5] Massachusetts Gen Hosp, Boston, MA 02114 USA
[6] Creighton Univ, Sch Med, Phoenix, AZ USA
[7] Kenya Govt Med Res Ctr, Nairobi, Kenya
[8] Harvard Med Sch, Boston, MA 02115 USA