Funding for this research was provided by:
World Health Organization (2019/949124)
Received: 13 March 2020
Accepted: 21 May 2020
First Online: 23 June 2020
Ethics approval and consent to participate
: Not applicable.
: The full version of the evidence synthesis was published by WHO’s Regional Office for Europe, and all the data used for the report and this Opinion piece are publicly available.
: The authors have no competing interests to declare. AB is a member of the World Health Organization European Advisory Committee on Health Research. SH was co-editor of <i>Health Research Policy and Systems</i> from 2006 to 2017.