[1] Right Care, Johannesburg, South Africa
[2] Univ Witwatersrand, Sch Clin Med, Dept Internal Med, Hlth Econ & Epidemiol Res Off, Johannesburg, South Africa
[3] Univ Pretoria, Dept Med Virol, Natl Hlth Lab Serv, Pretoria, South Africa
[4] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Epidemiol, Chapel Hill, NC 27515 USA
[5] Univ Witwatersrand, Fac Hlth Sci, Dept Internal Med, Clin HIV Res Unit, Johannesburg, South Africa