[1] Right Care, Johannesburg, South Africa
[2] Univ Witwatersrand, Dept Internal Med, Clin HIV Res Unit, Fac Hlth Sci, Johannesburg, South Africa
[3] Julius Clin Res, Zeist, Netherlands
[4] Univ Witwatersrand, Dept Anat Pathol, Cytol Unit, Natl Hlth Lab Serv,Fac Hlth Sci, Johannesburg, South Africa
[5] Univ Cape Town, Inst Infect Dis & Mol Med, Div Med Virol, Dept Pathol, Cape Town, South Africa
[6] Groote Schuur Hosp, Natl Hlth Lab Serv, Cape Town, South Africa
[7] Univ N Carolina, Dept Biostat, Gillings Sch Global Publ Hlth, Chapel Hill, NC USA
[8] Weill Cornell Med, Div Infect Dis, 53 W 23rd St,6th Floor, New York, NY 10010 USA