[1] Stellenbosch Univ, Fac Med & Hlth Sci, Dept Pediat & Child Hlth, Cape Town, South Africa
[2] Tygerberg Hosp, Cape Town, South Africa
[3] Imperial Coll London, MRC Ctr Global Infect Dis Anal, Sch Publ Hlth, London, England
[4] Univ Cape Town, Red Cross Childrens Hosp, Dept Pediat & Child Hlth, Haematol Oncol Serv, Cape Town, South Africa
[5] Univ Free State, Dept Pediat, Bloemfontein, South Africa
[6] Univ Hosp Bloemfontein, Bloemfontein, South Africa
[7] Univ Witwatersrand, Dept Pediat & Child Hlth, Johannesburg, South Africa
[8] Chris Hani Baragwanath Acad Hosp, Johannesburg, South Africa
[9] Univ Witwatersrand, Fac Hlth Sci, Sch Clin Med, Div Pediat Hematol Oncol,Dept Pediat & Child Hlth, Johannesburg, South Africa
[10] Charlotte Maxeke Johannesburg Acad Hosp, Johannesburg, South Africa
[11] Groote Schuur Hosp, Dept Radiat Oncol, Cape Town, South Africa
[12] Univ Cape Town, Fac Hlth Sci, Cape Town, South Africa
[13] Groote Schuur Hosp, Dept Ophthalmol, Cape Town, South Africa