The impact of lockdown measures on COVID-19: a worldwide comparison

  1. DI Papadopoulos
  2. I Donkov
  3. K Charitopoulos
  4. S Bishara

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Abstract

Objective

We aimed to determine which aspects of the COVID-19 national response are independent predictors of COVID-19 mortality and case numbers.

Design

Comparative observational study between nations using publicly available data.

Setting

Worldwide Participants Covid-19 patients

Interventions

Stringency of 11 lockdown policies recorded by the Blavatnik School of Government database and earliness of each policy relative to first recorded national cases

Main outcome measures

Association with log 10 National deaths (LogD) and log 10 National cases (LogC) on the 29 th April 2020 corrected for predictive demographic variables

Results

Early introduction was associated with reduced mortality (n=137) and case numbers (n=150) for every policy aside from testing policy, contact tracing and workplace closure. Maximum policy stringency was only found to be associated with reduced mortality (p=0·003) or case numbers (p=0·010) for international travel restrictions. A multivariate model, generated using demographic parameters (r 2 =0·72 for LogD and r 2 =0·74 for LogC), was used to assess the timing of each policy. Early introduction of first measure (significance p=0·048, regression coefficient β=-0·004, 95% confidence interval 0 to -0·008), early international travel restrictions (p=0·042, β=-0·005, -0·001 to - 0·009) and early public information (p=0·021, β=-0·005, -0·001 to -0·009) were associated with reduced LogC. Early introduction of first measure (p=0·003, β=-0·007, -0·003 to -0·011), early international travel restrictions (p=0·003, β=-0·008, -0·004 to-0·012), early public information (p=0·003, β=-0·007, 0·003 to -0·011), early generalised workplace closure (p=0·031, β=-0·012, -0·002 to -0·022) and early generalised school closure (p=0·050, β=-0·012, 0 to -0·024) were associated with reduced LogC.

Conclusions

At this stage in the pandemic, early institution of public information, international travel restrictions, and workplace closure are associated with reduced COVID-19 mortality and maintaining these policies may help control the pandemic.

What is already known on this topic

The COVID-19 pandemic has spread rapidly throughout the world and presented vast healthcare, economic and political challenges. Many nations have recently passed the peak of their infection rate, and are weighing up relaxation of lockdown strategies. Though the effect of individual lockdown policies can be estimated by modelling, little is known about the impact of individual policies on population case numbers or mortality through comparison of differing strategies between nations. A PubMed search was carried out on the 14/5/20 using keywords including “novel coronavirus-infected pneumonia”, “2019-nCoV”, “Sars-Cov-2”, “Covid-19”, “lockdown”,” policy”, “social distancing”, “isolation”, “quarantine” and “contact tracing” returned 258 studies in total. Following scanning of the above results, we found 19 studies that have examined the effect of lockdown within a region, which have demonstrated a reduction in case numbers after the introduction of a lockdown. There are no previous studies that have compared the effectiveness of government lockdowns between nations to determine the effectiveness of specific policies.

What this study adds

This study examines the corollary between government policy and COVID-19 case numbers and mortality, correct as of the 29th of April 2020, for every nation that there is available date within the Blavatnik School of Government database on COVID-19 policy. The study demonstrates that early generalised school closure, early generalised workplace closure, early restriction of international travel and early public information campaigns are independently associated with reduced national COVID-19 mortality. The maximum stringency of individual lockdown policies were not associated with reduced case numbers or mortality. Early reintroduction of these policies may be most effective in a relapse of the pandemic, though, school closure, workplace closure and restriction of international travel carry heavy politico-economic implications. There was no measurable effect of maximum stringency of lockdown policy on outcome at this point in time, indicating that early timing of lockdown introduction is of greater importance than its stringency, provided that the resultant viral reproductive rate is less than 1.

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  1. Version published to 10.1101/2020.05.22.20106476v2 on medRxiv
  2. ScreenIT

    SciScore for 10.1101/2020.05.22.20106476: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    All statistical analysis was carried out by IBM SPSS.
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Despite these limitations, the model used here has a high concordance with observed data with r2=0·72 for LogD and 0·74 for LogC. More precise models with r2=0·84 could have been achieved with further factors, at the expense of loss of data and overloading competing COVID-19 responses which may be associated with each other. As much as possible in the multivariate model, we aimed to only include pre pandemic demographics as predictive factors, though it was necessary to include the date of the first death within a country. One of the difficulties with the comparison is that, at this time, both the intervention and the outcome are time dependent. We sought to account for the timing of intervention by counting it within the same time frame for every country and for the timing of the outcome by using the date of the first death as a factor, although it may have been determined in part by the COVID-19 policy. The model is only of utility at one point in time, is in no way predictive and only served to test the lockdown policies. The size of the effect here from the multivariate regression, taking closing of schools as an example, is such that implementing the policy 24 days earlier was associated with halving of the mortality as of the 29th of April 2020. The measurable effect of introducing several policies together would be less than additive, as their introduction is associated with each other, though if the 3 most statistically significant factors (generalisation of workplace...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  3. Version published to 10.1101/2020.05.22.20106476v1 on medRxiv