PONE-D-20-17348

The basic reproduction number can be accurately estimated within 14 days after societal lockdown: The early stage of the COVID-19 epidemic in Denmark

PLOS ONE

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Reviewers' comments:

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Comments to the Author

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Reviewer #1: Yes

Reviewer #2: Partly

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Reviewer #1: Yes

Reviewer #2: I Don't Know

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Reviewer #1: No

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: No

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Reviewer #1: the authors' aim was to determine "the time from a political strategy have been enforced until the effect can be accurately estimated". Furthermore they aimed to estimate the fraction of infected individuals that are symptomatic and the average infection period. the primary analysis focuses on basic reproduction number before and after lockdown. The population in study is represented by the Danish National Health authority in-patient registry.

comments:

#1 in the methods section it should be stated if Danish National Health authority in-patient registry data are available on a public repository or not.

# 2 the authors should better address in the discussion a major limitation: the analysis was made on an in-patient population and not int the whole population: how could this bias the results?

# 3 there is a couple of papers that should be interesting to discuss:

- Alexandre Hyafil , David Moriña. Analysis of the impact of lockdown on the reproduction number of the SARS-Cov-2 in Spain. Gac Sanit . 2020 May 23;S0213-9111(20)30098-4. doi: 0.1016/j.gaceta.2020.05.003. Online ahead of print.

- Greg Dropkin. COVID-19 UK Lockdown Forecasts and R 0. Front Public Health. 2020 May 29;8:256. doi: 10.3389/fpubh.2020.00256. eCollection 2020.

Reviewer #2: Thank you for sharing your work. I find the overall theme of your work interesting. However, there are some points that should be addressed. The manuscript needs some language editing. I think with the help of a native speaker, you can signficantly improve the quality of your work. You have chosen to use the number of admitted patients, ICU admissions and deaths to calculate the basic reproduction number for COVID-19 spread; Were all of these patients confirmed as COVID-19 positive? In literature, we read about incubation times of up to 14 days. Yet you chose an icubation time of 4.7 days. Why?

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Reviewer #1: No

Reviewer #2: No

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The basic reproduction number can be accurately estimated within 14 days after societal lockdown: The early stage of the COVID-19 epidemic in Denmark

PONE-D-20-17348R1

Dear Dr. Valentin,

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.

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Kind regards,

Chiara Lazzeri

Academic Editor

PLOS ONE

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