[1] USAID, Off Populat & Reprod Hlth, Washington, DC USA
[2] Univ Illinois, Sch Publ Hlth, Div Epidemiol & Biostat, 1603 W Taylor St, Chicago, IL 60612 USA
[3] United Nations Childrens Fund UNICEF, Program Div, HIV Sect, New York, NY USA
[4] USAID, Off HIV AIDS, Washington, DC USA