1. South African Medical Research Council; Cochrane South Africa; Francie van Zijl Drive, Parow Valley Cape Town Western Cape South Africa 7505
2. University of Cape Town Health Sciences; Primary Health Care Directorate; Old Main Building, Groote Schuur Hospital E47-25 Cape Town South Africa 7925
3. School of Public Health and Family Medicine, University of Cape Town; Centre for Infectious Disease Epidemiology and Research (CIDER); 7 Alfred St., Observatory 7925 Cape Town South Africa
4. South African Medical Research Council; Health Systems Research Unit; Cape Town South Africa
5. University of Erfurt; Center for Empirical Research in Economics and Behavioral Sciences; Media and Communication Science; Erfurt Thuringia Germany 99089