-->PONE-D-26-08812-->-->Covid-19 Related Excess Mortality: An Analysis by Age for Selected Countries-->-->PLOS One

Dear Dr. Madden,

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.

Both reviewers acknowledge the scientific merit of the study and the robustness of the statistical analyses. However, they have identified several areas that require substantial improvement. The abstract should be restructured to include key quantitative results, such as correlation coefficients, effect sizes, and significance levels, and the manuscript would benefit from a more consistent IMRAD structure to improve clarity and readability. The introduction should more explicitly state the research gap, novelty, and relevance of the study, with additional references to prior studies on COVID-19-related excess mortality and age-specific analyses.

The methodology section requires clearer articulation of the rationale for selecting specific datasets and countries, along with detailed explanations of data sources, comparability, and the generalizability of the findings. In terms of results presentation, certain tables are dense and would benefit from graphical representations to enhance interpretability, and some descriptive or interpretive content in the results section should be moved to the discussion.

The discussion should clarify the added value of the study for general audiences, compare findings with existing local and international studies, and explicitly describe the strengths and limitations of the study design. The conclusions should be concise and directly linked to the main findings.

Overall, the reviewers agree that the study is relevant and potentially valuable, but substantial revisions are required to improve clarity, scientific presentation, and contextualization of results. I recommend that the authors be invited to revise the manuscript in accordance with the reviewers’ comments and resubmit for further evaluation. A detailed point-by-point response addressing each reviewer’s comment should accompany the revised submission.

Please submit your revised manuscript by May 24 2026 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 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.

As the corresponding author, your ORCID iD is verified in the submission system and will appear in the published article. PLOS supports the use of ORCID, and we encourage all coauthors to register for an ORCID iD and use it as well. Please encourage your coauthors to verify their ORCID iD within the submission system before final acceptance, as unverified ORCID iDs will not appear in the published article. Only  the individual author can complete the verification step; PLOS staff cannot  verify ORCID iDs on behalf of authors.

We look forward to receiving your revised manuscript.

Kind regards,

Muhammad Umair, 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. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Additional Editor Comments (if provided):

I am writing regarding the manuscript entitled “Covid-19 Related Excess Mortality: An Analysis by Age for Selected Countries” (PONE-D-26-08812), submitted to PLOS ONE. After careful evaluation of the peer reviews, I recommend that the manuscript undergo major revision before it can be considered for acceptance.

Both reviewers acknowledge the scientific merit of the study and the robustness of the statistical analyses. However, they have identified several areas that require substantial improvement. The abstract should be restructured to include key quantitative results, such as correlation coefficients, effect sizes, and significance levels, and the manuscript would benefit from a more consistent IMRAD structure to improve clarity and readability. The introduction should more explicitly state the research gap, novelty, and relevance of the study, with additional references to prior studies on COVID-19-related excess mortality and age-specific analyses.

The methodology section requires clearer articulation of the rationale for selecting specific datasets and countries, along with detailed explanations of data sources, comparability, and the generalizability of the findings. In terms of results presentation, certain tables are dense and would benefit from graphical representations to enhance interpretability, and some descriptive or interpretive content in the results section should be moved to the discussion.

The discussion should clarify the added value of the study for general audiences, compare findings with existing local and international studies, and explicitly describe the strengths and limitations of the study design. The conclusions should be concise and directly linked to the main findings.

Overall, the reviewers agree that the study is relevant and potentially valuable, but substantial revisions are required to improve clarity, scientific presentation, and contextualization of results. I recommend that the authors be invited to revise the manuscript in accordance with the reviewers’ comments and resubmit for further evaluation. A detailed point-by-point response addressing each reviewer’s comment should accompany the revised submission.

Thank you for considering this recommendation. I remain available to provide further guidance as needed.

[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: Partly

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

-->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: I read this manuscript with interest, as it addresses an important and timely topic COVID-19-related excess mortality across countries and age groups. The study raises relevant questions regarding the role of age standardization and socioeconomic factors in interpreting mortality patterns. However, several aspects of the manuscript, particularly the abstract and overall structure, require substantial improvement.

The abstract in its current form is not sufficiently structured and lacks key quantitative details. While it outlines the general analytical approach, it does not provide specific numerical results (e.g., correlation coefficients, effect sizes, or statistical significance levels), which limits its scientific clarity and impact. A more structured abstract (background, methods, results, conclusions) with clearly reported numerical findings is strongly recommended.

More broadly, the manuscript is difficult to follow due to the lack of adherence to a clear IMRAD structure. The introduction does not adequately establish the relevance and novelty of the study. It lacks a clear articulation of the research gap and does not sufficiently reference key prior studies in the field of excess mortality during COVID-19. Strengthening the justification of the study and situating it within existing literature would significantly improve the manuscript.

The methodology section requires clearer and more structured description. In particular, the rationale for selecting the specific dataset and the included countries is not sufficiently explained. It would be important to clarify why these countries were chosen, what makes them comparable or analytically meaningful, and how this selection supports the study objectives and potential generalizability of findings.

The presentation of results could also be improved. Correlation analyses would be more effectively communicated through graphical representations rather than relying predominantly on tables. Some tables appear overly dense and reduce readability; in particular, tables with country rankings could be moved to supplementary materials.

Finally, the conclusions should be more concise and clearly linked to the main findings, with a stronger emphasis on their implications.

Overall, while the study is relevant and potentially valuable, substantial revisions are needed to improve clarity, structure, and scientific presentation.

Reviewer #2: Dear Authors,

Congrats for the manuscript. It has scientific merit, however some clarifications should be made for general audiences who can not be familiar with the technical nature of the topic. For example, added value with this study should be obviously explained in the discussion. You should give clear explanations on why your findings differed from various studies and strengths, and drawbacks with your study design. This revisions will lead your discussion part getting confident with scope. Additionally, there exist plenty of sentences in findings section that can easily go to the discussion, so your own findings should remain in their places. Lastly, during the covid pandemic period, both local studies and comparative studies were published to evaluate excess mortality, so you may consider to discuss your results with their excess mortality data.

Kind regards,

Reviewer

**********

-->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: Yes:  Natalya Glushkova

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.]

To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures

You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation.

NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications.

Covid-19 Related Excess Mortality: An Analysis by Age for Selected Countries

PONE-D-26-08812R1

Dear Dr. Madden,

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 will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support.

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,

Muhammad Umair, Ph.D.

Academic Editor

PLOS One

Additional Editor Comments (optional):

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 #2: All comments have been addressed

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 #2: Yes

Reviewer #3: Yes

**********

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

Reviewer #2: Yes

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 #2: Yes

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 #2: Yes

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 #2: Thanks for considering the recommendations from both of the reviewers. The scientific merit has been increased. Good luck for the publication.

Reviewer #3: I have no additional comments for the author, including concerns about dual publication, research ethics, or publication ethics.

**********

-->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 #2: No

Reviewer #3: No

**********