PONE-D-20-12267

COVID-19 Pandemic and Farr's Law: a global comparison and prediction of outbreak acceleration and deceleration rates

PLOS ONE

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Academic Editor

PLOS ONE

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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: Partly

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

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: Abstract:

Page 8- Need expansion of COVID-19

Need a brief explanation of why Farr’s laws used in the declaration of rates?

Since the generalization is not possible, region can be mentioned in the title of the paper

Introduction:

Please elaborate on the limitations of the Farr's law and its use in models

Materials and methods:

Isn’t there a need to consider the mobility of the population which has a high potential to alter the changes of cases especially in the case of infectious diseases such as COVID-19

On what criteria used to identify cases, like socio-demographic information.

Under the data author need not keep the URL link of Worldometer since, It is already provided in the reference l

Results:

62% from Europe, 25% from America, 6% from Asia and 6% from America-Here America is repeated twice (USA v/s rest of america, north or south, ? need to explain)

If actual numbers mentioned with percentage, it would give better understanding.

The cases of countries which mostly recovered from COVID can be mentioned and a comparison of the actual time of recovery and that predicted by this model can be mentioned. This can also be mentioned in the tables across to the predicted date as well as the actual date of the last case reported in that particular country.

Discussion:

Findings from other models, differences in the obtained findings compared to other models could be elaborated in discussion, pointing out the added value of using Farr’s law.

Comparison of countries depending on age demographics, recovery time can be included in discussion.

Reviewer #2: Reviewer: Dr. Farshad Farzadfar

Fregni et al. provided a study to investigate Farr’s law in the COVID-19 pandemic. The authors tried to come up with an efficient model to predict acceleration and deceleration rates of the COVID-19 outbreak and probable time of outbreak relative resolution.

Although the authors inspected mentioned notion well, several issues are necessary to be considered, including:

1. In the abstract, it is mentioned that COVID-19 data until April 10, 2020, is utilized for modeling, wasn’t is possible to use newer data for this study?

2. In the introduction, the authors mention that the importance of this study is to prepare the medical system against epidemics. Still, the final results of the study may implicate deceleration and endpoints of the epidemic more prominent. The main goal of the study should be highlighted.

3. Telling the life story of Mr. Farr in the introduction seems to be unnecessary for understanding the aim of this study. Besides, introducing components of Farr’s law in the introduction instead of the methods part can be more useful.

4. The first and second ratios (R1 and R2) are explained vaguely in the methods.

5. Are Worldometer website data on COVID-19 statistics reliable enough to use in such a study? Is there any previous evidence one quality of their statistics? Data quality? Different criteria for diagnosis?

6. Does the “predefined hypothesis that higher R1 and R2 ratios are correlated with higher numbers of cases or deaths” sentence has a reference? Especially about predicting deaths this claim is more questionable.

7. Data presented in S2 and S3 tablets are not consistent with prediction numbers for new cases and new deaths beyond 10th June 2020.

8. The results of the study are not well discussed in the discussion part. More detailed benefits of the results of the study could help readers more, and offer more solutions for health policymakers.

9. Numbers of countries reaching values near zero in new cases and deaths are not discussed that make how much population and talking socioeconomic status of these countries could help more.

10. The conclusion part does not conclude the main message of the study. A warning message for high-risk areas, according to predictions discussed, could be more beneficial.

Reviewer #3: This is an interesting study based on the very old and forgot Farr's law.

I only recommend to comment in the Discussion section the influence of the different political actions against the SARS-CoV-2, and to compare the very symmetric curve of figure 1 with the current epidemiological situation (perhaps in addendum at the lat moment).

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Reviewer #1: Yes: Giridhara R Babu, NOLITA DOLCY SALDANHA

Reviewer #2: No

Reviewer #3: No

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Attachments

Attachment

Submitted filename: COVID-19 Pandemic and Farrs Law - final review.docx

COVID-19 Pandemic and Farr's Law: a global comparison and prediction of outbreak acceleration and deceleration rates

PONE-D-20-12267R1

Dear Dr. Fregni,

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,

Amir Radfar, MD,MPH,MSc,DHSc

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 #4: 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 #2: Yes

Reviewer #4: Yes

**********

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

Reviewer #2: Yes

Reviewer #4: 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 #4: Yes

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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 #2: Yes

Reviewer #4: 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: I appreciate the efforts of the authors for making the manuscript more suitable for publication and considering the suggested comments for revision. Here I want to discuss the answers and propose further comments:

C1. I thank the authors for updating the data and doing a part of modeling on the updated data. However, I could not find the mentioned supplementary figure 3 in the attached files and links.

C2. So, the main goal of the study is explained well. You can provide this answer in the introduction part to make the goal of the study clearer.

C3. Thank you for removing the Farr’s biography and describing the law in the introduction.

C4. Expanded explanation of the calculation of R1 and R2 ratios is a positive change, and I thank the authors.

C5. Enough evidence and suitable references are provided for the validity of the Worldometer website and data.

C6. The added reference for the comment and the corrected claim of authors seem to be more logical now in the context of Farr’s law.

C7. The authors did well with adding an explanation to table 1 as legend and make the data and results easier to understand for readers of the article.

C8. Adding the suggested parts to the discussion (as the discussion on demographic and socioeconomic status and political actions of the countries) to help health policymakers is another positive change in the manuscript made by the authors and it is respectful.

C9. The revised discussion part has covered this comment.

C10. A revised conclusion of the study seemed to be necessary to warn the high-risk areas, and I thank the authors for considering this comment in their manuscript.

Reviewer #4: (No Response)

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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 #4: No