Funding for this research was provided by:
Seventh Framework Programme (278186)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (233850/2014-7)
National Institute for Health Research
Received: 28 September 2017
Accepted: 21 December 2017
First Online: 16 January 2018
Ethics approval and consent to participate
: All participants provided informed consent before the start of the study. The study was approved by the corresponding local ethics committees of participating countries. In Belgium, the study was approved by the ethics committee of Ghent University Hospital, in The Netherlands by the Medical Ethics Committee of the VU University Medical Center in Amsterdam, in Hungary by the Health Science Council, Scientific Research Ethic Committee, in France by the Commission Nationale de l’Informatique et des Libertés and in the UK by The London School of Hygiene & Tropical Medicine Ethics Committee.
: Not applicable.
: The authors declare that they have no competing interests
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