[1] Univ Calif Los Angeles, David Geffen Sch Med, 10833 Conte Ave, Los Angeles, CA 90095 USA
[2] Univ Calif San Diego, Dept Med, Div Infect Dis & Global Hlth, La Jolla, CA 92093 USA
[3] Botswana UPenn Partnership, Gaborone, Botswana
[4] Botswana Harvard AIDS Inst Partnership, Botswana Sexual & Reprod Hlth Initiat, Gaborone, Botswana
[5] Univ Botswana, Dept Med, Gaborone, Botswana
[6] Univ Southern Calif, Dept Prevent Med, Los Angeles, CA 90007 USA
[7] Univ Liverpool Liverpool Sch Trop Med, Liverpool, Merseyside, England