[1] London Sch Hyg & Trop Med, Fac Infect & Trop Dis, Dept Clin Res, London, England
[2] Botswana Harvard AIDS Inst Partnership, Private Bag BO320, Gaborone, Botswana
[3] Botswana Univ Pennsylvania Partnership, Gaborone, Botswana
[4] Univ Penn, Perelman Sch Med, Div Infect Dis, Philadelphia, PA 19104 USA
[5] St Georges Univ London, Inst Infect & Immun, Ctr Global Hlth, London, England