1 Department of Health Services Research and Policy, Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London WC1 9SH, UK. Electronic address: luisa.pettigrew@lshtm.ac.uk.
2 Department of Family Medicine and Primary Health Care, Ghent University, Ghent, Belgium.
3 Department of Family and Community Medicine, Rio de Janeiro State University, Rio de Janeiro, Brasil.
4 Family Medicine Unit, Department of Community Health, School of Public Health, University of Ghana, Accra, Ghana.
5 Faculty of Medicine, Nursing and Health Sciences, Flinders University, Adelaide, Australia.
6 Department of Social and Environmental Health Research, Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London WC1 9SH, UK.