Footnotes

• Contributors KR, AE, CC, AS, UV, VV and MNM have written their responses, and the final version of the letter based on the written responses and email discussion was summarized and formulated by MNM. The discussion was coordinated by KR. The authors have revised and agreed on the final version of the manuscript after several revisions.

• Competing interests None declared.

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