[1] London Sch Hyg & Trop Med, Fac Infect & Trop Dis, Clin Res Dept, London, England
[2] Biomed Res & Training Inst, Harare, Zimbabwe
[3] London Sch Hyg & Trop Med, Fac Epidemiol & Populat Hlth, Dept Infect Dis Epidemiol, MRC Int Stat & Epidemiol Grp, London, England
[4] London Sch Hyg & Trop Med, Dept Infect Dis Epidemiol, Fac Epidemiol & Populat Hlth, London, England
[5] London Sch Hyg & Trop Med, Dept Populat Hlth, Fac Epidemiol & Populat Hlth, London, England
[6] Univ Zimbabwe, Coll Hlth Sci, Dept Radiol, Harare, Zimbabwe
[7] Univ Southampton, MRC Lifecourse Epidemiol Unit, Southampton, Hants, England
[8] Univ Zimbabwe, Dept Paediat, Harare, Zimbabwe
[9] Univ Bristol, Bristol Med Sch, Musculoskeletal Res Unit, Translat Hlth Sci, Bristol, Avon, England