[1] Univ Pretoria, Kalafong Hosp, Dept Paediat, Fac Hlth Sci, Private Bag X396, ZA-0001 Pretoria, South Africa
[2] Kalafong Prov Tertiary Hosp, Pretoria, South Africa
[3] Univ Witwatersrand, Dept Paediat & Child Hlth, Fac Hlth Sci, Johannesburg, South Africa
[4] Natl Inst Communicable Dis, Natl Hlth Lab Serv, Ctr HIV & STIs, Johannesburg, South Africa
[5] North West Univ, Med Usage South Africa, Sch Pharm, Fac Hlth Sci, Potchefstroom, South Africa
[6] Thembisa Prov Tertiary Hosp, Pretoria, South Africa