1. Department of Primary and Community Care, Radboud University, Medical Centre , Nijmegen , the Netherlands
2. Nivel – Netherlands Institute for Health Services Research , Utrecht , the Netherlands
3. Centre for Global Health, Usher Institute, University of Edinburgh , Edinburgh , UK
4. Faculty of Behavioural and Social Sciences, University of Groningen , Groningen , the Netherlands
5. Centre for Infectious Disease Control (CIb), National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands