Footnotes

• Contributors Both authors conceived and designed this correspondence. MS drafted the manuscript. JL reviewed and revised the manuscript. Both authors approved 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.

• Patient consent for publication Not required.

• Provenance and peer review Not commissioned; externally peer reviewed.