1. Umeå Centre for Global Health Research, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
2. MRC/Wits Rural Public Health and Health Transitions Research UnitSchool of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
3. PB is Deputy Editor of Global Health Action but played no part in the editorial process for this paper
4. Department of Epidemiology and Public HealthSwiss Tropical and Public Health Institute, Basel, Switzerland
5. University of Basel Basel, Switzerland
6. Melbourne School of Population and Global HealthUniversity of Melbourne, Carlton, Australia