Studies demonstrate the relative effectiveness of different social distancing measures
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Multiple peer-reviewed studies and systematic reviews examine and evaluate the effectiveness of various social distancing measures and nonpharmaceutical interventions during disease outbreaks.
<h4>Background</h4>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and is spread person-to-person through close contact. We aimed to investigate the effects of physical distance, face masks, and eye protection on virus transmission in health-care and non-health-care (eg, community) settings.<h4>Methods</h4>We did a systematic review and meta-analysis to investigate the optimum distance for avoiding person-to-person virus transmission and to assess the use of face masks and eye protection to prevent transmission of viruses. We obtained data for SARS-CoV-2 and the betacoronaviruses that cause severe acute respiratory syndrome, and Middle East respiratory syndrome from 21 standard WHO-specific and COVID-19-specific sources. We searched these data sources from database inception to May 3, 2020, with no restriction by language, for comparative studies and for contextual factors of acceptability, feasibility, resource use, and equity. We screened records, extracted data, and assessed risk of bias in duplicate. We did frequentist and Bayesian meta-analyses and random-effects meta-regressions. We rated the certainty of evidence according to Cochrane methods and the GRADE approach. This study is registered with PROSPERO, CRD42020177047.<h4>Findings</h4>Our search identified 172 observational studies across 16 countries and six continents, with no randomised controlled trials and 44 relevant comparative studies in health-care and non-health-care settings (n=25 697 patients). Transmission of viruses was lower with physical distancing of 1 m or more, compared with a distance of less than 1 m (n=10 736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] -10·2%, 95% CI -11·5 to -7·5; moderate certainty); protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; p<sub>interaction</sub>=0·041; moderate certainty). Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD -14·3%, -15·9 to -10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12-16-layer cotton masks; p<sub>interaction</sub>=0·090; posterior probability >95%, low certainty). Eye protection also was associated with less infection (n=3713; aOR 0·22, 95% CI 0·12 to 0·39, RD -10·6%, 95% CI -12·5 to -7·7; low certainty). Unadjusted studies and subgroup and sensitivity analyses showed similar findings.<h4>Interpretation</h4>The findings of this systematic review and meta-analysis support physical distancing of 1 m or more and provide quantitative estimates for models and contact tracing to inform policy. Optimum use of face masks, respirators, and eye protection in public and health-care settings should be informed by these findings and contextual factors. Robust randomised trials are needed to better inform the evidence for these interventions, but this systematic appraisal of currently best available evidence might inform interim guidance.<h4>Funding</h4>World Health Organization.
Objective Social distancing is one of the main non-pharmaceutical interventions used in the control of the COVID-19 pandemic. This scoping review aims to synthesise research findings on the effectiveness of different types and levels of social distancing measures in the earlier stage of COVID-19 pandemic without the confounding effect of mass vaccination. Design Scoping review. Data sources MEDLINE, Embase, Global Health and four other databases were searched for eligible studies on social distancing for COVID-19 published from inception of the databases to 30 September 2020. Study selection and data extraction Effectiveness studies on social distancing between individuals, school closures, workplace/business closures, public transport restrictions and partial/full lockdown were included. Non-English articles, studies in healthcare settings or not based on empirical data were excluded. Results After screening 1638 abstracts and 8 additional articles from other sources, 41 studies were included for synthesis of findings. The review found that the outcomes of social distancing measures were mainly indicated by changes in Rt, incidence and mortality, along with indirect indicators such as daily contact frequency and travel distance. There was adequate empirical evidence for the effect of social distancing at the individual level, and for partial or full lockdown at the community level. However, at the level of social settings, the evidence was moderate for school closure, and was limited for workplace/business closures as single targeted interventions. There was no evidence for a separate effect of public transport restriction. Conclusions In the community setting, there was stronger evidence for the combined effect of different social distancing interventions than for a single intervention. As fatigue of preventive behaviours is an issue in public health agenda, future studies should analyse the risks in specific settings such as eateries and entertainment to implement and evaluate measures which are proportionate to the risk.
In the absence of any pharmacological intervention, one approach to slowing the COVID-19 pandemic is reducing the contact rate in the population through social distancing. Governments the world over have instituted different measures to increase social distancing but information on their effectiveness in reducing mobility is lacking. We analyzed the mobility data from 41 cities to look at the effect of these interventions. The median mobility across cities on March 2, 2020 was 100% (IQR: 94%, 107%), which decreased to a median of 10% (IQR: 7%, 17%) on March 26, 2020. We found that the mobility decreased on average by 3.4% (95%CI: 3.3%, 3.6%) per day from March 2 through March 26. Social distancing measures decreased the mobility by an additional 23% (95%CI: 20%, 27%). Our study provides initial evidence for the reduction in mobility in cities instituting social distancing measures.
Nonpharmaceutical Interventions (NPI) consist of compulsory (isolation, quarantine, stay-at-home orders, banning public gatherings, nonessential business closures, school closures), and voluntary (social distancing, handwashing, respiratory etiquette, and universal mask wearing) measures. The aim of this narrative review is to evaluate the different forms of NPI and their effectiveness in combating the pandemic. Isolation can be indicated for symptomatic and asymptomatic infected people at home or at hospitals depending on the patient's clinical picture. Quarantine is a social distancing intervention in asymptomatic uninfected people who had contact with SARS-CoV-2 infected individuals. Stay-at-home orders refer to statewide mandates imposing nonessential business closures, prohibition of public events and gatherings, and travel restrictions. Studies have suggested that stay-at-home orders may be associated with a reduction in the incidence of COVID-19 in some countries. Mask wearing decreases the risk of COVID-19 in the community, especially when the surgical masks are used for vulnerable people. N-95 respirators protect health workers from COVID-19. NPI may be helpful to curb the COVID-19 pandemic while mass vaccination worldwide is not attainable, and the threat of SARS-COV-2 variants remain on the horizon.
Abstract Introduction Social distancing measures (SDMs) protect public health from the outbreak of coronavirus disease 2019 (COVID-19). However, the impact of SDMs has been inconsistent and unclear. This study aims to assess the effects of SDMs (e.g. isolation, quarantine) for reducing the transmission of COVID-19. Methods and analysis We will conduct a systematic review meta-analysis research of both randomised controlled trials and non-randomised controlled trials. We will search MEDLINE, EMBASE, Allied & Complementary Medicine, COVID-19 Research and WHO database on COVID-19 for primary studies assessing the effects of SDMs (e.g. isolation, quarantine) for reducing the transmission of COVID-19, and will be reported in accordance with PRISMA statement. The PRISMA-P checklist will be used while preparing this protocol. We will use Joanna Briggs Institute guidelines (JBI Critical Appraisal Checklists) to assess the methodological qualities and synthesised performing thematic analysis. Two reviewers will independently screen the papers and extracted data. If sufficient data are available, the random-effects model for meta-analysis will be performed to measure the effect size of SDMs or the strengths of relationships. To assess the heterogeneity of effects, I 2 together with the observed effects (Q-value, with degrees of freedom) will be used to provide the true effects in the analysis. Ethics and dissemination Ethics approval and consent will not be required for this systematic review of the literature as it does not involve human participation. We will be able to disseminate the study findings using the following strategies: we will be publishing at least one paper in peer-reviewed journals, and an abstract will be presented at suitable national/international conferences or workshops. We will also share important information with public health authorities as well as with the World Health Organization. In addition, we may post the submitted manuscript under review to bioRxiv, medRxiv, or other relevant pre-print servers. Strengths and limitations of this study To our knowledge, this study will be the first systematic review to examine the impact of social distancing measures to reduce transmission of COVID-19. This study will offer highest level of evidence for informed decisions, drawing a broader framework. This protocol reduces the possibility of duplication, provides transparency to the methods and procedures that will be used, minimise potential biases and allows peer-review. This research is not externally funded, and therefore time and resource will be constrained. If included studies will be variable in sample size, quality and population, which may open to bias, and the heterogeneity of data will preclude a meaningful meta-analysis to measure the impact of specific SDMs
Abstract Background : Social distancing measures (SDMs) protect the health of the public from coronavirus 2019 (COVID-19) infection. However, the impact of SDMs has been inconsistent and unclear. This study aims to review the factors impacting SDMs (e.g. isolation, quarantine) for reducing the transmission of COVID-19. Methods : A systematic review was conducted. We searched MEDLINE, EMBASE, Allied & Complementary Medicine, COVID-19 Research and WHO database on COVID-19 for primary studies assessing the enablers and barriers associated with SDMs, and reported in accordance with PRISMA statement. We used JBI Critical Appraisal Checklist for the cross-sectional survey and Qualitative Research to assess the methodological qualities and synthesised performing thematic analysis. Two reviewers independently screened the papers and extracted data. Results: A total of 1235 citations were identified, of which 16 were found to be relevant. The studies reported in two broad categories, under seven separate themes: positive impact of SDMs, effective public health interventions, positive change in people’s behaviour, worries and concerns about COVID-19, roles of mass media, physical and psychological impacts, and ethnicity/age associated with COVID-19. Conclusion : The identified evidence signals that SDMs are generally effective for preventing or reducing transmission. There is a scope and need to find the best methods and approaches at the primary healthcare level in terms of developing objective measures and interventions to establish the link between different factors and SDMs and reducing transmission of COVID-19 trend effectively, efficiently and equitably.
Abstract
Aims
Nonpharmaceutical interventions against the spread of SARS-CoV-2 in Germany included the cancellation of mass events (from March 8), closures of schools and child day care facilities (from March 16) as well as a “lockdown” (from March 23). This study attempts to assess the effectiveness of these interventions in terms of revealing their impact on infections over time.
Methods
Dates of infections were estimated from official German case data by incorporating the incubation period and an empirical reporting delay. Exponential growth models for infections and reproduction numbers were estimated and investigated with respect to change points in the time series.
Results
A significant decline of daily and cumulative infections as well as reproduction numbers is found at March 8 (CI [7, 9]), March 10 (CI [9, 11] and March 3 (CI [2, 4]), respectively. Further declines and stabilizations are found in the end of March. There is also a change point in new infections at April 19 (CI [18, 20]), but daily infections still show a negative growth. From March 19 (CI [18, 20]), the reproduction numbers fluctuate on a level below one.
Conclusions
The decline of infections in early March 2020 can be attributed to relatively small interventions and voluntary behavioural changes. Additional effects of later interventions cannot be detected clearly. Liberalizations of measures did not induce a re-increase of infections. Thus, the effectiveness of most German interventions remains questionable. Moreover, assessing of interventions is impeded by the estimation of true infection dates and the influence of test volume.
ial distancing measures for COVID-19 at individual, community and national levels and social settings assessed by different outcome parameters.
This review analyses the level of evidence for different types and levels of social distancing measures.
Findings in varied outcome parameters could not be compared directly.
Non-English literature was excluded from this review.
Introduction
Social distancing is one of the main non-pharmaceutical interventions (NPIs) to control the outbreak of COVID-19 worldwide. Social distancing, also known as physical distancing, is based on the premise that the rate of transmission of infectious diseases will decrease if people in communities stay at home from work or school, avoid large gatherings and refrain from having physical contact with each other. WHO guidelines describe social distancing measures at the individual level (eg, keeping at least one metre from each other) and the community level including stay-at-home recommendation/ordinances and measures in specific socioeconomic settings (eg, workplace, schools, eateries, entertainment and parties). 1 2 At the national or regional levels, lockdown (also called ‘community quarantine’ to restrict movement of population groups) may be imposed as an extreme form of social distancing, 3 4 where it can be a total or partial lockdown to restrict key socioeconomic activities. 5
Despite the fact that social distancing measures have become a crucial strategy globally in mitigating COVID-19 pandemic, the evidence for their effectiveness is just slowly accruing. Earlier studies applied mathematical modelling to predict effectiveness of social distancing measures. 6–9 Recent studies evaluated the outcomes retrospectively using empirical data and reported the outcomes within specific parameters. A study which analysed data from 149 countries suggested that implementation of different social distancing interventions was associated with an overall reduction in COVID-19 incidence of 13% (incident
uld be overestimating the effect of social distancing in persons < 19 years of age. Strong evidence suggests that children have milder COVID-19 symptoms than adults and might be less infectious ( 23 ). More studies are needed clarify the role children play in SARS-CoV-2 transmission. In our models, we assumed death and hospitalization rates would be similar to those experienced in Wuhan, where older age groups have been the most affected. Because different countries have different population structures and different healthcare infrastructure, including varying numbers of hospital beds, ventilators, and intensive care unit beds, effects of social distancing interventions could vary widely in different places.
Our results align with an increasing number of publications estimating the effects of interventions against COVID-19. Several researchers have investigated how social distancing interventions in Wuhan might have affected the trajectory of the outbreak ( 30 , 35 , 36 ; J. Zhang, unpub. data, https://www.medrxiv.org/content/10.1101/2020.03.19.20039107v1 ). Others have investigated the effect of similar measures elsewhere and concluded that social distancing interventions alone will not be able to control the pandemic ( 37 , 38 ; M.A. Acuña-Zegarra, unpub. data, https://www.medrxiv.org/content/10.1101/2020.03.28.20046276v1 ; N.G. Davies, unpub. data, medrxiv.org/content/10.1101/2020.04.01.20049908v1 ; S. Kissler, unpub. data, https://www.medrxiv.org/content/10.1101/2020.03.22.20041079v1 ).
Taken together, our results suggest that more aggressive approaches should be taken to mitigate the transmission of SARS-CoV-2. Social distancing interventions need to occur in tandem with testing and contact tracing to minimize the burden of COVID-19. New information about the epidemiologic characteristics of SARS-CoV-2 continues to arise. Incorporating such information into mathematical models such as ours is key to providing public health officials with the best tools to ma
Au- thor. Wan, H., & Pfau, M. (2004). The relative effectiveness of inoculation, bolstering, and combined … widespread infectious disease outbreak is social distancing. Social distancing is a broad class of strategies ranging … different definitions proffered reflect the different social forms which frame the debate” (p. 146). Such
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