PGPH-D-22-00669

Snotwatch COVID-Toes: An ecological study of chilblains and COVID-19 diagnoses in Victoria, Australia

PLOS Global Public Health

Dear Dr. Sawires,

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Kevin Escandón, MD, MSc

Academic Editor

PLOS Global Public Health

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Reviewers' comments:

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Comments to the Author

1. Does this manuscript meet PLOS Global Public Health’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: No

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: 

- Abstract: I think that the conclusion is too strong. A ecological study cannot demonstrate an hypothesis. Consider using “suggest” or “support”.

- As temperature is a major confounder, I wonder how the model including only temperature has improved when the number of COVID diagnoses were added to the model. Could authors describe? Maybe using LR test.

- I suggest that the information in this paper could be relevant to the discussion and support the use of ecological methods.

- COVID toes were commonly associated with positive results in the family members, not the patient. doi: 10.1016/j.annder.2020.11.005. 

Reviewer #2:

I have one major concern that should be addressed:

- The authors conclude that they demonstrate a method that could support tracking of COVID-19 viral spread in the community. I strongly disagree with this finding. The study included a subset of 3,687 confirmed cases of COVID-19 at a time where the number of confirmed cases in the population under study was close to 40,000. I believe this study's findings are strongly biased by increased likelihood of patients presenting to a GP if they had COVID-19 and then also subsequently developed chilblains. The study is still publishable, but with the removal of the conclusion for the method having potential as a surrogate measure for the spread of COVID-19 infections. I suggest the conclusion should be more focused on increasing clinician awareness of the potential for chilblains in their COVID-19 patients - not anything to do with surveillance for COVID-19.

Other minor comments are:

- Lines 145-146 - sentence starting with We obtained ... does not make sense - use of BOM

- The increased RR for 0-16 year olds is likely associated with the increased likelihood of parents to take their children to the GP with the combined conditions. This should be made clear in the paper and references included to show that this is a known phenomenon.

- Please label Table 1 more appropriately, footnote any abbreviations, and include numbers in the Table.

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Reviewer #1: No

Reviewer #2: No

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Snotwatch COVID-Toes: An ecological study of chilblains and COVID-19 diagnoses in Victoria, Australia

PGPH-D-22-00669R1

Dear Miss Sawires,

We are pleased to inform you that your manuscript 'Snotwatch COVID-Toes: An ecological study of chilblains and COVID-19 diagnoses in Victoria, Australia' has been provisionally accepted for publication in PLOS Global Public Health.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow up email. A member of our team will be in touch with a set of requests.

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

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Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Global Public Health.

Best regards,

Kevin Escandón, MD, MSc

Academic Editor

PLOS Global Public Health

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