Footnotes

• Contributors COI conceived and designed the study with substantial contribution from UIHE. Initial draft was done by COI and revised by UIHE. Both authors approve the manuscript for submission.

• 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 Not commissioned; internally peer reviewed.