[1] Univ Cape Town, Inst Infect Dis & Mol Med, Clin Infect Dis Res Initiat, ZA-7925 Cape Town, Western Cape, South Africa
[2] Univ Cape Town, Dept Med, ZA-7925 Cape Town, Western Cape, South Africa
[3] Univ Cape Town, Inst Infect Dis & Mol Med, Dept Clin Lab Sci, Computat Biol Grp, ZA-7925 Cape Town, Western Cape, South Africa
[4] Univ London Imperial Coll Sci Technol & Med, Dept Med, London, England
[5] MRC Natl Inst Med Res, London, England