Footnotes

• Twitter @elboghdadly, @nickdblack

• Contributors KEl-B drafted the initial manuscript. All authors reviewed and commented on the manuscript, and substantially contributed to the final manuscript.

• 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.