[1] Biomed Res & Training Inst, Hlth Res Unit Zimbabwe, 10 Seagrave Rd, Avondale, Harare, Zimbabwe
[2] London Sch Hyg & Trop Med, Dept Infect Dis Epidemiol, Fac Epidemiol & Populat Hlth, London, England
[3] Univ Teaching Hosp, Lusaka, Zambia
[4] Univ Zimbabwe, Dept Paediat, Harare, Zimbabwe
[5] London Sch Hyg & Trop Med, Fac Epidemiol & Populat Hlth, MRC Int Stat & Epidemiol Grp, London, England
[6] Univ Southampton, MRC Lifecourse Epidemiol Ctr, Human Dev & Hlth, Southampton, England
[7] London Sch Hyg & Trop Med, Fac Infect & Trop Dis, Clin Res Dept, London, England
[8] Univ Bristol, Bristol Med Sch, Musculoskeletal Res Unit, Global Musculoskeletal Res Grp, Bristol, England