[1] Ctr Microbiol Res, Kenya Med Res Inst, Nairobi, Kenya
[2] Univ Nairobi, Dept Obstet & Gynecol, Nairobi, Kenya
[3] Univ Nairobi, Dept Math, Nairobi, Kenya
[4] Univ Nairobi, Dept Med Microbiol, Nairobi, Kenya
[5] Univ Washington, Dept Obstet & Gynecol, Seattle, WA 98195 USA
[6] Univ Washington, Dept Lab Med, Seattle, WA 98195 USA
[7] Univ Washington, Dept Med, Seattle, WA 98195 USA
[8] Univ Calif San Francisco, Fred Hutchinson Canc Res Ctr, Program Biostat, San Francisco, CA 94143 USA
[9] Univ Calif San Francisco, Dept Obstet Gynecol & Reprod Sci, San Francisco, CA 94143 USA