[1] Brighton & Sussex Med Sch, Global Hlth & Infect Dept, Brighton, E Sussex, England
[2] London Sch Hyg & Trop Med, Clin Res Dept, London, England
[3] Univ KwaZulu Natal, Edendale Hosp, Dept Internal Med, Pietermaritzburg, South Africa
[4] London Sch Hyg & Trop Med, Dept Infect Dis Epidemiol, London, England
[5] Univ Witwatersrand, Sch Publ Hlth, Johannesburg, South Africa
[6] Malawi Liverpool Wellcome Trust Clin Res Programm, Blantyre, Malawi
[7] UCL, Inst Global Hlth, Off Caper St, London WC1E 6JB, England