Peer Review History

Original SubmissionFebruary 3, 2023
Decision Letter - Om Prakash Choudhary, Editor

PONE-D-23-03172Patterns of testing in the extensive Danish national SARS-CoV-2 test set-upPLOS ONE

Dear Dr. Gram, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. The manuscript will be re-evaluated after minor revisions as suggested by the reviewers.

Please submit your revised manuscript by Apr 17 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.
If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Om Prakash Choudhary, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at 

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and 

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Thank you for stating the following in the Acknowledgments Section of your manuscript: 

"..Many structures in Danish society contributed to establishing and running the test centres, special contributions were given by the Novo Nordic Foundation (Grant number: NNF20SA0063854), Novo Nordisk Denmark (providing staff), McKinsey (sourcing) and the Danish Military (logistical support)."

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. 

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: 

"The authors received no specific funding for this work."

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

3. In your Data Availability statement, you have not specified where the minimal data set underlying the results described in your manuscript can be found. PLOS defines a study's minimal data set as the underlying data used to reach the conclusions drawn in the manuscript and any additional data required to replicate the reported study findings in their entirety. All PLOS journals require that the minimal data set be made fully available. For more information about our data policy, please see http://journals.plos.org/plosone/s/data-availability.

Upon re-submitting your revised manuscript, please upload your study’s minimal underlying data set as either Supporting Information files or to a stable, public repository and include the relevant URLs, DOIs, or accession numbers within your revised cover letter. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories. Any potentially identifying patient information must be fully anonymized.

Important: If there are ethical or legal restrictions to sharing your data publicly, please explain these restrictions in detail. Please see our guidelines for more information on what we consider unacceptable restrictions to publicly sharing data: http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Note that it is not acceptable for the authors to be the sole named individuals responsible for ensuring data access.

We will update your Data Availability statement to reflect the information you provide in your cover letter.

4. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript.

5. Please upload a new copy of Figures 1 and 2 as the detail is not clear. Please follow the link for more information:

https://blogs.plos.org/plos/2019/06/looking-good-tips-for-creating-your-plos-figures-graphics/

https://blogs.plos.org/plos/2019/06/looking-good-tips-for-creating-your-plos-figures-graphics/

6. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

********** 

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

Reviewer #1: Yes

Reviewer #2: I Don't Know

********** 

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

********** 

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

********** 

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 manuscript titled "Patterns of testing in the extensive Danish national SARS-CoV-2 test set-up" is an interesting study.

I appreciate the authors' topic. The authors clearly defined the research questions in the background section. However, the following comments need to be addressed, and the authors should improve their manuscript in the following aspects:

1. Please improve the quality of the manuscript.

2. This research is important and useful because it will help improve the COVID-19 national health system in every country. This will make it easier to find out things like who is infected or has no symptoms.

Has a comparable study been done in other countries? I think it will help improve the adoption of health programs in the future.

And on the basis of that, a unique regulation was established. Mention it if the answer is positive.

I am aware that the number of samples required for statistical analysis is enormous, but you could summarize the key points of the data in Table 3 in a graph in order to prevent generalization and scattering and to facilitate content transfer for better understanding.

Reviewer #2: Dear authors, overall, the manuscript is well written & presents an excellent results, I don't have any scientific revision, only I have comments about figures quality it should be replaced with a good ones.

Best wishes

********** 

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Revision 1

Response to editor and reviewers

Thank you for taking the time to comment on our manuscript. Your comments have been very helpful to improve the manuscript. The information has been added to the manuscript and a point-by-point response is included below.

Journal Requirements

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

Response: Thank you for sharing the templates. The manuscript has been revised to meet the style requirements.

2. Thank you for stating the following in the Acknowledgments Section of your manuscript:

"..Many structures in Danish society contributed to establishing and running the test centres, special contributions were given by the Novo Nordic Foundation (Grant number: NNF20SA0063854), Novo Nordisk Denmark (providing staff), McKinsey (sourcing) and the Danish Military (logistical support)."

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:

"The authors received no specific funding for this work."

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

Response: Thank you for pointing this out. We have removed the funding-related information from the manuscript. The authors received no funding for the work presented in this paper. However, many structures in Danish society contributed to establishing and running the test centres, special contributions were given by the Novo Nordic Foundation (Grant number: NNF20SA0063854), Novo Nordisk Denmark (providing staff), McKinsey (sourcing) and the Danish Military (logistical support). Can we include this information in the supporting file?

3. In your Data Availability statement, you have not specified where the minimal data set underlying the results described in your manuscript can be found. PLOS defines a study's minimal data set as the underlying data used to reach the conclusions drawn in the manuscript and any additional data required to replicate the reported study findings in their entirety. All PLOS journals require that the minimal data set be made fully available. For more information about our data policy, please see http://journals.plos.org/plosone/s/data-availability.

Upon re-submitting your revised manuscript, please upload your study’s minimal underlying data set as either Supporting Information files or to a stable, public repository and include the relevant URLs, DOIs, or accession numbers within your revised cover letter. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories. Any potentially identifying patient information must be fully anonymized.

Important: If there are ethical or legal restrictions to sharing your data publicly, please explain these restrictions in detail. Please see our guidelines for more information on what we consider unacceptable restrictions to publicly sharing data: http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Note that it is not acceptable for the authors to be the sole named individuals responsible for ensuring data access.

We will update your Data Availability statement to reflect the information you provide in your cover letter.

Response: Thank you. The underlying dataset, which consists of more than 120 million data rows, contains person identifiable information concerning most of the Danish population. We are not in a position to share this and we believe that we have provided an explanation for this already. Should we have misunderstood, we’re of course happy to discuss what to do. The text we previously provided reads:

“The data material used involve information on every person living in Denmark within the study period. Data cannot be shared publicly because they may only be accessed and register-coupled within a secure data analysis environment. However, de-identified participant-level data are available for Institutional Data access to members of the scientific and medical community for non-commercial use only. Applications should be submitted to Forskerservice (https://sundhedsdatastyrelsen.dk/da/forskerservice) at The Danish Health Data Authority, where they will be reviewed on the basis of relevance and scientific merit. Data are available now, with no defined end date.”

4. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript.

Response: The ethic statement has been moved to the Methods section and deleted from any other section.

5. Please upload a new copy of Figures 1 and 2 as the detail is not clear. Please follow the link for more information:

https://blogs.plos.org/plos/2019/06/looking-good-tips-for-creating-your-plos-figures-graphics/

https://blogs.plos.org/plos/2019/06/looking-good-tips-for-creating-your-plos-figures-graphics/

Response: Thank you for giving us the opportunity to improve the quality of the figures. The figures have been re-created in R studio instead of excel, which makes it easier to adjust the dimensions and resolution. Please let us know if the new version of the figures appears blurry.

6. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Response: We have ensured that the reference list is complete and correct.

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 manuscript titled "Patterns of testing in the extensive Danish national SARS-CoV-2 test set-up" is an interesting study.

I appreciate the authors' topic. The authors clearly defined the research questions in the background section. However, the following comments need to be addressed, and the authors should improve their manuscript in the following aspects:

1. Please improve the quality of the manuscript.

Response: We believe that, with the number of changes we’ve made to the manuscript, including the new figure, the overall quality of the manuscript has improved considerably. We hope by this to have responded adequately to this comment by the reviewer.

2. This research is important and useful because it will help improve the COVID-19 national health system in every country. This will make it easier to find out things like who is infected or has no symptoms.

Has a comparable study been done in other countries? I think it will help improve the adoption of health programs in the future.

And on the basis of that, a unique regulation was established. Mention it if the answer is positive.

I am aware that the number of samples required for statistical analysis is enormous, but you could summarize the key points of the data in Table 3 in a graph in order to prevent generalization and scattering and to facilitate content transfer for better understanding.

Response: To our knowledge no comparable studies have been done in other countries. We appreciate your suggestion of visualizing the data in Table 3 which we have followed. The results in Table 3 are now shown in Fig 3. We believe this new figure provide a better overview of the results of the analysis. Table 3 has been moved to Supplementary and appears as S3 Table. We decided to keep the table in supplementary because it adds additional information of number of events and person-years.

Reviewer #2: Dear authors, overall, the manuscript is well written & presents an excellent results, I don't have any scientific revision, only I have comments about figures quality it should be replaced with a good ones. Best wishes.

Response: Thank you so much for your comments. The figures have been re-created in R studio instead of excel, which makes it easier to adjust the dimensions and resolution to ensure high quality.

Attachments
Attachment
Submitted filename: Response to Reviewers.docx
Decision Letter - Marwan Osman, Editor

PONE-D-23-03172R1Patterns of testing in the extensive Danish national SARS-CoV-2 test set-upPLOS ONE

Dear Dr. Gram,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Aug 17 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.
If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Marwan Osman

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #3: Yes

**********

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

Reviewer #3: Yes

**********

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #3: Yes

**********

6. 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 #3: The authors provide interesting insights on the use of COVID-19 test during the pandemic. The topic is overall interesting, but some clarification need to be addressed:

1) Could you specify if there were mandatory testing before attending mass gathering events, especially during the first wave

2) Authors have identified two tracks for testing : healthcare track/community track. It would be interesting to report results stratified by tracks, to see the weight of each track in the overall testing policy

3) Is there any ways to combine the database of PCR and Rapid antigen testing? I would interesting to have all analyses pooled, esp:

- How many people did not have neither a PCR nor a Rapid antigen test

- What is the proportion, at individual level, of test being done by PCR and Rapid antigen, if those who had rapid antigen also had PCR to confirm the diagnosis. In the latter case, if there were discrepancies.

- Authors barely mentionned the rate of positive PCR tests (only in a figure), it would be of interest to have a more detailed look

4) Discussion is too long, with comments that are not related to results being presented

5) The association between vaccination and testing should be more elaborated : those having > 2 doses may be person at risks (immmunocompromised), and thus be more tested in the context of their healthcare plan (hence the value of looking at the different testing tracks).

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #3: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Revision 2

Journal Requirements

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Response: We have reviewed the reference list to ensure that it is complete and correct.

Review Comments to the Author

1) Could you specify if there were mandatory testing before attending mass gathering events, especially during the first wave

Response: Thank you for your valuable comment. We appreciate your consideration of our findings. We agree that test requirements played an important role in the testing patterns. Throughout the pandemic various restrictions including test requirements were implemented and lifted depending on the development of the pandemic. Our colleagues have done a great work describing the restrictions in Figure 1 in a published study (Munch PK, Espenhain L, Hansen CH, Krause TG, Ethelberg S. Case-control study of activities associated with SARS-CoV-2 infection in an adult unvaccinated population and overview of societal COVID-19 epidemic counter measures in Denmark. PLoS One. 2022;17(11):e0268849. doi: 10.1371/journal.pone.0268849). In our study we briefly mention the restrictions and cite our colleagues study for further information. “During certain periods a negative PCR-test was necessary in order take part in civil life (e.g. access to sport/public institutions, restaurants, public cultural activities or foreign travel) [27]. Further, staff at hospitals, nursing homes and home care have actively been encouraged to be voluntarily tested at their workplace several times a week for prolonged periods. Similarly, school children and students were tested weekly or biweekly in some periods [27].”

2) Authors have identified two tracks for testing: healthcare track/community track. It would be interesting to report results stratified by tracks, to see the weight of each track in the overall testing policy

Response: Thank you for your suggestion. As described in the manuscript, the proportion of PCR-test performed in the healthcare track was only 16.6%. In the supplementary material, we included the results of a sub-analysis including only PCR-tests from the community track, which showed the same associations as the main analysis. However, the older age groups were PCR-tested less in the community track compared to when the community and the healthcare track was analysed as a group (S3 Table).

3) Is there any ways to combine the database of PCR and Rapid antigen testing? I would interesting to have all analyses pooled, esp:

- How many people did not have neither a PCR nor a Rapid antigen test

- What is the proportion, at individual level, of test being done by PCR and Rapid antigen, if those who had rapid antigen also had PCR to confirm the diagnosis. In the latter case, if there were discrepancies.

- Authors barely mentioned the rate of positive PCR tests (only in a figure), it would be of interest to have a more detailed look

Response: Thank you for your valuable comment. During the epidemic, the PCR-test results were the primary basis for surveillance and national incidence figures. Moreover, PCR-tests have been primarily utilized in epidemiological studies. Individuals who tested positive by rapid antigen test were advised to have the infection confirmed in a subsequent PCR test. Therefore, we decided not to include rapid antigen-tests in all analyses. We added information about the proportion of individuals never PCR- or rapid antigen-tested (5.4%) to the manuscript (page 10). Lastly, we are not quite certain about what extra details of the positive PCR-tests the reviewer find relevant to include in the manuscript.

4) Discussion is too long, with comments that are not related to results being presented

Response: We thank the reviewer for this comment. However, we are not quite certain where precisely the reviewer suggests to shorten the Discussion. We feel, naturally, that the Discussion is of adequate length and that it covers the presented results. Also, this point had not previously been raised. Since decisions concerning the length of the manuscript also involve journal policy, we might suggest to keep the discussion at its present length and leave it to the editorial office, to decide if it should be rewritten.

5) The association between vaccination and testing should be more elaborated: those having > 2 doses may be person at risks (immmunocompromised), and thus be more tested in the context of their healthcare plan (hence the value of looking at the different testing tracks).

Response: We appreciate your comments and the time you have dedicated to review our work. In response to the specific point raised, we would like to address that individuals aged 18 years or above were offered 3 vaccine doses and the vaccination coverage in the total study population was above 60% (figure 1). Therefore, we do not believe that individuals having more than two doses are at higher risk or immunocompromised. We hope that you agree.

Attachments
Attachment
Submitted filename: Response to Reviewers.docx
Decision Letter - Marwan Osman, Editor

Patterns of testing in the extensive Danish national SARS-CoV-2 test set-up

PONE-D-23-03172R2

Dear Dr. Gram,

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.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Marwan Osman

Academic Editor

PLOS ONE

Formally Accepted
Acceptance Letter - Marwan Osman, Editor

PONE-D-23-03172R2

Patterns of testing in the extensive Danish national SARS-CoV-2 test set-up

Dear Dr. Gram:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Marwan Osman

Academic Editor

PLOS ONE

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .