PONE-D-23-27681Temporary Disability (TD) registry as a complementary system to traditional epidemiological surveillance during the COVID-19 pandemic in Spain a National Study.PLOS ONE

Dear Dr. Culqui L.,

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 has merit and generally exhibits a well-structured format. It addresses pertinent issues that could enhance our understanding of the post-COVID landscape. However, the three ad hoc reviewers have pointed out the need for improvements in the text, particularly regarding its comparability with other research in the field. They also highlight the necessity for greater clarity in elucidating concepts, methods, and limitations of the study, aspects with which I fully agree upon my review. Therefore, I suggest that the authors carefully consider the reviewers' suggestions and implement them to refine the presentation of the manuscript.

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Ricardo de Mattos Russo Rafael, Ph.D.

Academic Editor

PLOS ONE

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Reviewers' comments:

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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: Partly

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: I Don't Know

Reviewer #3: Yes

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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

Reviewer #3: Yes

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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

Reviewer #3: 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: INTRODUCTION

1. In the following excerpt: “The Social Security system processed 4.18 million TDs related to COVID-19 from January 2020 to May 1, 2021. Of these, 1.4 million were due to the infection and 2.78 million were due to close contacts with confirmed COVID -19 cases [7]”, why does the data presented have the cutoff point of May 1, 2021 and not the end of the period observed by the study? It would make more sense to present the updated data until December 31, 2021.

METHODOLOGY

2. In the excerpt: “…We used the daily incidence rate of COVID-19 in patients between 16 and 65 years old in Spain as the dependent variable, referred to as IRRenave”, complete with the information “per 100,000 inhabitants”, as also in the excerpt: “As the independent variable, we used the daily incidence rate of TD, referred to as IRTD…”. The information that the indicator was calculated per 100,000 inhabitants only appears in the fifth paragraph, which doesn't make much sense.

3. It is necessary to explain that in the IRRenave indicator, the inclusion criteria for the age group - from 16 to 65 years old – is due to the fact that it is the age group that benefits from TD, in order to allow the comparison of indicators. This is not clear in the Methodology and is only explained in the Discussion.

4. I suggest moving the section “The daily IRRenave was calculated per 100,000 inhabitants in Spain, based on the number of cases registered in RENAVE...”, in order to take into account what was exposed in item 2.

5. Correct “Both TDRenave and IRTD”, to “Both IRRenave and IRTD”.

RESULTS

6. In the paragraph: “Figure 1 shows the description of the complete series of 638 days…”, please review and correct the periods, which are defined differently from that exposed in the Methodology section. “…as well as the pre-vaccination period (March 10, 2020, to December 26, 2020), post-vaccination period (December 27, 2020, to December 31, 2021)”.

7. Correct the period of the first wave in the graph: “10-03-20 to 26-06-20”.

Reviewer #2: This is a short original article where a temporary disability registry (TD) is assessed as a complimentary system to the standard epidemiological surveillance during the first months of the COVID-19 pandemic in Spain.

The authors should try to improve some of the wording (i.e. Introduction, first paragraph: there is no declaration of a pandemic by WHO: WHO declares a PHEIC; COVID-19 is the disease: SARS-CoV-2 is the etiological agent and cause of the disease).

The main concerns related to this paper is the surveillance system that are compared as well as the statistical analysis.

1.- Surveillance system:

The epidemiological surveillance system in Spain was totally overwhelmed in the firsts waves of the pandemic. There were not enough PCR tests and the case definitions was very strictly defined, reducing the number of people tested nearly only to those with severe disease admitted to hospitals as well as Health Care Workers. Is is therefore widely admitted that there was a sizable amount of underestimation of COVID-19 cases.

The TD exceptional surveillance system relies in a personal declaration, usually by phone, where the individual with symptoms and/od that considers him o herself a close contact of a confirmed COVID-case asked for a Temporary Disability leave. There is no any clinical evaluation of the sick leave request, nor any confirmation of the likely diagnosis nor the status of close contact.

Furthermore, Spain institutes a special situation for business and other economic activities called “ERTE” a temporary regulatory employment file, where all or a significant number of workers are entitled to stay at home because of a temporal closure of the economic activity due to the lockdowns. It is likely that many of these workers do not request for a TD leave, albeit they could have been infected and/or close contact of a COVID-19 cases. Both system: being under an ERTE and the TD are incompatible.

In summary, neither the epidemiological surveillance system nor the TD complementary system were both reliable nor accurate systems for assessing the caseload of COVID-19 in Spain over the first waves of the pandemic. As an example, over the period March 10, 2020, to December 31, 2021, the authors state that 4,8 M COVID cases were reported to the epidemiological surveillance system. Our-World-In Data registry indicates more than 6 M COVID-19 cases over the same period.

Several of these limitations (and others as well) are discussed by the authors, but the main conclusion, i.e. that the TD registry could be a useful as a system to complement traditional epidemiological surveillance is weak enough if applied to the COVID-19 pandemic.

2.- Statistical analysis:

I suggest that the analysis should be reviewed by a statistician.

Reviewer #3: The manuscript aimed to explore whether Temporary Disability (TD) could complement the traditional Spanish surveillance system. The authors clearly defined the study's scope, connecting it to current literature. While the methodology and statistical analyses were generally appropriate, some adjustments are needed. More detailed presentation of results is warranted, and the discussion, though robust, brings the benefit from substantiation and comparisons with other studies, along with acknowledgment of significant limitations. This article underscores the potential of complementary systems, traditionally utilized in other countries, to serve as crucial early warning tools for epidemiological surveillance and public health in Spain.

Comments

1- Title suggestion: Temporary Disability (TD) registry as a complementary system to traditional epidemiological surveillance during the COVID-19 pandemic in Spain.

2- The keywords do not represent the entire manuscript content. Consider incorporating keywords such as Health Surveillance System or Epidemiological Monitoring for a more comprehensive representation.

3- Introduction (Page 3, 4th paragraph) - Insert reference in "In addition, on March 12, another royal decree-law included … and the tourism sector."

4- Introduction (Page 3, 7th paragraph) - It would be interesting to explain the delay and difference in the number of notifications between the systems. How do these systems work in Spain?

5- Methodology (Page 5, 2th paragraph) - Specify the age range used.

6- Methodology (Page 5, 6th paragraph) - Explain the transformations used in IRTD_1 e IRRenave_2.

7- Methodology (Page 6, 2th paragraph) - It would be interesting to explain better why the 14-day time interval and what was the level of significance adopted.

8- Results (Page 7, 2th paragraph) - Check the correct pre and post vaccination period.

9- Figure 1 - Insert the end of the observation period (31/12//2021) on the x-axis. Adjust the lines for the pre and post vaccination periods.

10- Figure 2 - It would be important to improve figure quality in order to better visualization.

11- Figure 3 - It would be important to improve the quality and shape of the figure. Furthermore, it's necessary to correct the 3 a) figure title. “Cross correlation for the complete series (638 days)”.

12- In Table 2, include a note and specify (*). Clarify any relevant information indicated by the asterisk.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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PONE-D-23-27681R1Temporary Disability (TD) registry as a complementary system to traditional epidemiological surveillance during the COVID-19 pandemic in Spain a National Study.PLOS ONE

Dear Dr. Culqui L.,

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 Apr 12 2024 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 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,

Ricardo de Mattos Russo Rafael, Ph.D.

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.

Additional Editor Comments:

Please carry out the correction indicated by reviewer 1

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 #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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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 #1: Yes

Reviewer #2: (No Response)

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

Reviewer #1: Yes

Reviewer #2: (No Response)

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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 #1: Yes

Reviewer #2: (No Response)

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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 #1: Yes

Reviewer #2: (No Response)

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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 #1: The paragraph that explains Figure 1, in Results section, remains with incorrect dates in this new version. Please review.

Reviewer #2: (No Response)

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Reviewer #1: No

Reviewer #2: No

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Temporary Disability (TD) registry as a complementary system to traditional epidemiological surveillance during the COVID-19 pandemic in Spain a National Study.

PONE-D-23-27681R2

Dear Dr. Culqui L.,

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Kind regards,

Ricardo de Mattos Russo Rafael, Ph.D.

Academic Editor

PLOS ONE

Reviewers' comments: