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PONE-D-21-25144Potential SARS-CoV-2 infectiousness among asymptomatic healthcare workersPLOS ONE

Dear Dr. Pimenoff,

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Cristian Apetrei, MD, PhD

Academic Editor

PLOS ONE

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"This work was supported by the Karolinska University Hospital (KUH); the County Council of Stockholm; Erling-Persson family foundation; KTH Royal Institute of Technology; Creades and SciLifeLab. There were no roles for the funders in design or execution of the study, in analysis and interpretation of data or in the decision to submit for publication"

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"This work was supported by the Karolinska University Hospital (KUH); the County Council of Stockholm; Erling-Persson family foundation; KTH Royal Institute of Technology; Creades and SciLifeLab. There were no roles for the funders in design or execution of the study, in analysis and interpretation of data or in the decision to submit for publication."

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

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Reviewer #1: No

Reviewer #2: Yes

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

Reviewer #1: No

Reviewer #2: I Don't Know

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3. Have the authors made all data underlying the findings in their manuscript fully available?

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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: The primary objective of a secondary study was to quantify the proportion of healthcare workers who were potentially infectious. Their sick leave was classified as post-symptomatic or pre-symptomatic, and virus-positive subjects with no sick leave were considered asymptomatic. About 0.2% of he HCW at work were potentially infectious and pre-symptomatic (later had disease) and 0.17% were potentially infectious and asymptomatic (never took sick leave). In summary, 33% and 28% of all the 57 potentially infectious subjects were pre-symptomatic or asymptomatic, respectively.

Major revisions:

Include a statistical analysis section which lists and describes all the statistical methods used to analysis the data; cite the statistical software used.

Minor revisions:

1- Abstract: Replace “neither” with “either.”

2- Provide the percentage that corresponds to 16/57.

3- Table 2: Provide corresponding percentages for categorical factors. For instance, for sex provide the percentage corresponding to 44/(44+13) Female & 13/(44+13) Male, and 7488/(7488+1961) Female & 1961/(7488+1961) Male.

4- To assist in the review process, please add page and line numbers to the document.

Reviewer #2: This study identified the proportion of potentially infectious, nonsymptomatic HCWs which are either pre-symptomatic, asymptomatic or post-symptomatic. This topic is highlighted by WHO which mention the importance of this decisive factor on the spread of the pandemic.

The authors tested an impressive number of HCWs from Karolinska University hospital, using methods described in detail in references 7 and 8: serology and RT PCR. Previously published studies (references 6, 9 and 10) by the same team of researchers, support the authors' interest in the real-time pandemic situation in Stockholm.

The results of this study that the younger HCWs are potentially more infectious, based on real laboratory data, and the conclusion that they should get vaccinated, could be used like a model for other EU countries, to motivate their HCWs and general population to vaccinate themselves.

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Reviewer #1: No

Reviewer #2: No

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Potential SARS-CoV-2 infectiousness among asymptomatic healthcare workers

PONE-D-21-25144R1

Dear Dr. Pimenoff,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Cristian Apetrei, MD, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments: