[1] Univ Witwatersrand, Fac Hlth Sci, Dept Immunol, Johannesburg, South Africa
[2] Natl Hlth Lab Serv, Johannesburg, South Africa
[3] Univ Witwatersrand, Fac Hlth Sci, Dept Mol Med & Haematol, Johannesburg, South Africa
[4] South African Hlth Prod Regulatory Author, Pretoria, South Africa
[5] South African Med Res Council, Pretoria, South Africa
[6] Univ Pretoria, Steve Biko Hosp, Dept Paediat, Pretoria, South Africa
[7] Univ Pretoria, Fac Hlth Sci, Sch Med, Pretoria, South Africa
[8] Univ Cape Town, Fac Hlth Sci, Dept Med Virol, Rondebosch, South Africa
[9] Stellenbosch Univ, Fac Med & Hlth Sci, Div Med Virol, Cape Town, South Africa
[10] Univ Witwatersrand, Wits Reprod Hlth & HIV Inst, Johannesburg, South Africa
[11] Univ Witwatersrand, Fac Hlth Sci, Dept Med, Clin HIV Res Unit, Johannesburg, South Africa
[12] Univ Witwatersrand, Fac Hlth Sci, Dept Chem Pathol, Johannesburg, South Africa