[1] Vanderbilt Univ, Sch Med, Inst Global Hlth, Nashville, TN 37212 USA
[2] Vanderbilt Univ, Sch Med, Dept Pediat, Nashville, TN 37212 USA
[3] Univ Teaching Hosp, Dept Paediat, Lusaka, Zambia
[4] Univ Zambia, Sch Med, Lusaka, Zambia
[5] Ctr Infect Dis Res Zambia, Lusaka, Zambia
[6] Fred Hutchinson Canc Res Ctr, Stat Ctr HIV AIDS Res & Prevent, Seattle, WA 98104 USA
[7] NICHHD, NIH, Bethesda, MD 20892 USA
[8] Muhimbili Univ, Dar Es Salaam, Tanzania
[9] Johns Hopkins Univ, Coll Med, Res Project, Blantyre, Malawi
[10] Family Hlth Int, Chapel Hill, NC USA
[11] Drexel Univ, Dept Obstet & Gynecol, Coll Med, Philadelphia, PA 19104 USA