Footnotes

• Handling editor Ellen J Weber

• Contributors The above authors are the sole authors of this letter. In the original paper, MV conducted the literature review and DS reviewed the findings and contributed to the final write up. Both MV and DS wrote this response letter.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Commissioned; internally peer reviewed.