Radon exposure and COVID-19 mortality in pre-vaccination period: What links might exist?

Jean François Coudert; Ekaterina Dadachova; Gilles Maignant; Stephanie Jonathan

doi:10.1371/journal.pone.0337320

Peer Review History

Original SubmissionDecember 16, 2024
27 May 2025 Decision Letter - Said Muhammad, Editor PONE-D-24-57007Radon exposure and COVID-19 mortality in pre-vaccination period: what links might exist?PLOS ONE Dear Dr. Jonathan, Thank you for submitting your manuscript to PLOS ONE. The reviewers recomended your mnauscript for publication in PLOS ONE subject to minor revision listed below. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. ============================== Thank you for submitting your manuscript to PLOS ONE. The reviewers recomended your mnauscript for publication in PLOS ONE subject to minor revision listed below. 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 Jul 11 2025 11:59PM. 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If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references.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 If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Additional Editor Comments (if provided): Manuscript Number: PONE-D-24-57007 Radon exposure and COVID-19 mortality in pre-vaccination period: what links might exist? Dear Stephanie Jonathan, M.D,   Thank you for submitting your manuscript to PLOS ONE. I have completed my evaluation of your manuscript. The reviewers recommend acceptance of your manuscript following minor revision and modification. I invite you to resubmit your manuscript after addressing the comments below. Please resubmit your revised manuscript within due time. When revising your manuscript, please consider all issues mentioned in the reviewers' comments carefully: please outline every change made in response to their comments and provide suitable rebuttals for any comments not addressed. Please note that your revised submission may need to be re-reviewed. [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: 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: This cross-sectional ecological study investigated the association between indoor radon exposure and COVID-19 mortality rates across eight countries, including several European nations, the United States, and the State of Kerala, India, during the pre-vaccination period. The results demonstrated a consistent negative correlation, indicating that regions with higher radon concentrations tended to experience lower COVID-19 mortality rates. Although the findings are not conclusive, the data suggest a potential mitigating effect of radon exposure on COVID-19 mortality. This unique research has the potential to pave the way for further studies, offering significant benefits to public health. Additionally, the manuscript is well-written, and the research is scientifically robust. Based on its merit and well-executed design, I recommend acceptance of this manuscript without any modifications. Reviewer #2: The manuscipt is well written in clear English. However there are minor gramattical suggestions highlited in the reviewed manuscript. Also the introduction section is very lengthy. some sections may be shifted to discussion section, like data and discussion of Kerala. ****** 6. 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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. Attachments Attachment Submitted filename: Radon and COVID-19 Plosone.pdf https://doi.org/10.1371/journal.pone.0337320.r001
Revision 1
27 Oct 2025 Author Response Response to Reviewers – Manuscript PONE-D-24-57007 Title: Radon exposure and COVID-19 mortality in pre-vaccination period: what links might exist? Dear Academic Editor and Reviewers, We sincerely thank you for your time, your positive evaluations, and the constructive comments provided during the review of our manuscript. We are pleased that both reviewers found the manuscript scientifically sound, well-written, and suitable for publication pending minor revisions. Please find below our detailed point-by-point responses. All modifications have been incorporated into the revised manuscript and tracked accordingly in the submitted version with changes. General Reviewer Feedback Reviewer 1: “This unique research has the potential to pave the way for further studies... Based on its merit and well-executed design, I recommend acceptance of this manuscript without any modifications.” Response: We thank Reviewer 1 for the positive feedback and support for our manuscript. No specific changes were requested. Reviewer 2: “The manuscript is well written in clear English. However, there are minor grammatical suggestions highlighted in the reviewed manuscript. Also, the introduction section is very lengthy. Some sections may be shifted to the discussion section, like data and discussion of Kerala.” Response: We appreciate Reviewer 2’s helpful suggestions. In response: 1. Grammar: We have carefully addressed all grammatical suggestions as indicated in the reviewer’s annotated file. (Line 85) 2. Introduction length: We agree the introduction was too long. We have shortened it by relocating the Kerala-specific background and interpretation to the Discussion section (lines 236–263) where it fits better with our results. Additionally, some parts related to the statistical study using French data have been moved from the Materials and Methods to the Discussion (lines 265–271). Figure numbering has been updated accordingly. 3. Clarification in the abstract: o Original: “The findings revealed a consistent negative correlation between higher radon concentrations and lower COVID-19 mortality rates.” o Revised: “The findings revealed a consistent negative correlation between radon concentrations and COVID-19 mortality rates, indicating that higher radon concentrations were associated with lower mortality rates.” Editorial and Journal Requirements 1. Style & Formatting: We have reviewed the PLOS ONE formatting guidelines and updated the manuscript and files to meet the style requirements, including proper file naming. 2. Figures 2 & 8 — Map image copyright: Figure 2 (European Atlas of Natural Radiation): We confirm that Figure 2 is adapted from the European Atlas of Natural Radiation by the European Commission’s Joint Research Centre (JRC). According to the European Commission Decision of 12 December 2011 on the reuse of Commission documents, this material is available under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence unless otherwise indicated. Figure 1. Description of the phenomenon involved in the risk evaluation of indoor radon. We received permission from the author, Peter Bossew, to reuse this figure, and we have attached the permission document accordingly. Figure 8 (USGS–EPA Open-File Report 93-292 previously figure 8. After revisions, it is figure 6): We confirm that Figure 8 is reproduced from the USGS–EPA Open-File Report 93-292, which is an official publication by U.S. federal agencies. Under U.S. law (17 U.S.C. § 105), works created by the U.S. government are in the public domain and are not subject to copyright restrictions. To comply with PLOS ONE’s policy, we have: o Verified that this material is in the public domain. o Updated the figure caption to include a clear public domain notice and correct source attribution. We hope this clarifies the licensing status of both figures and we remain available should the editorial team require any further information. 3. References: We have systematically checked all 45 references in five batches. None are retracted or under expression of concern. All DOIs are valid and the articles remain indexed on PubMed, PMC, and publisher sites. 4. Minor reference updates: We have updated a few references for completeness and corrected minor formatting issues. These changes are tracked in the revised manuscript: o Page 5 – source: ECDC, 2020 o Line 157 – INSEE, 2020 o Figure 6 – X and Y variable are now labelled We hope that our responses and revisions meet your expectations and would like to thank you again for your time and consideration. Kind regards, Stephanie Jonathan, M.D. (On behalf of all co-authors) Attachments Attachment Submitted filename: Rebuttal letter to reviewer_PLOSONE.docx https://doi.org/10.1371/journal.pone.0337320.r002
6 Nov 2025 Decision Letter - Said Muhammad, Editor Radon exposure and COVID-19 mortality in pre-vaccination period: what links might exist? PONE-D-24-57007R1 Dear Dr. Jonathan, 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, Said Muhammad Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0337320.r003
Formally Accepted
Acceptance Letter - Said Muhammad, Editor PONE-D-24-57007R1 PLOS ONE Dear Dr. Jonathan, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, 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. You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing. If we can help with anything else, please email us at customercare@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. Said Muhammad Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0337320.r004

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