[1] Univ Cape Town, Sch Publ Hlth & Family Med, ZA-7925 Cape Town, South Africa
[2] Prov Govt Western Cape, Med Sans Frontiers, Cape Town, South Africa
[3] Prov Govt Western Cape, Dept Hlth, Cape Town, South Africa
[4] Univ Cape Town, Div Clin Pharmacol, Dept Med, ZA-7925 Cape Town, South Africa