[1] Univ Witwatersrand, Fac Hlth Sci, Johannesburg, South Africa
[2] Univ Witwatersrand, Dept Med, Fac Hlth Sci, Hlth Econ & Epidemiol Res Off, ZA-2001 Johannesburg, South Africa
[3] Boston Univ, Ctr Global Hlth & Dev, Boston, MA 02215 USA
[4] Boston Univ, Sch Publ Hlth, Dept Int Hlth, Boston, MA USA
[5] Univ Cape Town, Desmond Tutu HIV Ctr, ZA-7925 Cape Town, South Africa
[6] Sch Pathol, Johannesburg, South Africa
[7] Wits Hlth Consortium, Johannesburg, South Africa
[8] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA 90095 USA