Impact of physical distancing policy on reducing transmission of SARS-CoV-2 globally: Perspective from government’s response and residents’ compliance

Background COVID-19 was declared a public health emergency by the World Health Organization (WHO) in January 2020. Various physical distancing interventions were introduced to flatten the epidemic curve and reduce the disease burden. We evaluated the impacts of policy stringency and residents’ compliance on time-varying reproduction number in 17 countries. Methods Data were from WHO reports of local transmission (February 28 to April 8, 2020) in Australia, Canada, Finland, France, Germany, Greece, Italy, Spain, Sweden, Thailand, the UK, US and Vietnam. Earlier local transmission data where available from press releases were added for Japan, South Korea, Singapore and Taiwan starting January 28, 2020. COVID-19 policy responses were from the Oxford Covid-19 Government Response Tracker with 17 indicators. Changes in people’s behaviors were from Google’s COVID-19 community mobility reports and Apple Maps’ mobility trends reports. We estimated the daily time-varying reproduction number (Rt) by country. 0-, 7- and 14-day lagged effects of non-pharmaceutical interventions and changes in human mobility on Rt were estimated by linear mixed-effects models. Results Rt initially surged rapidly, then declined gradually depending on policy stringency. The highest mean policy stringency scores were for Italy (69.97) and South Korea (61.00). Variations in stringency scores were higher in Europe, the US and Australia than in Asia. The human mobility reduction was greater in countries with strict policies (median stringency score > = 50). In terms of immediate (0-day lag) effects, Rt reductions were found for workplace-closure, limited-gathering, and stay-at-home policies. At a 7-day lag, Rt reductions were found for workplace closure, restrictions on gatherings, stay-at-home requirements, international travel controls, contact tracing and reducing walking around. At a 14-day lag, Rt reductions were found for restrictions on gatherings, less visiting and staying in parks, and reduced walking around. Conclusion The findings show physical distancing policies and residents’ compliance can slow transmission, with the lag-to-effect time varying by policy.

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Estimating the impact of physical distancing measures in containing COVID-19: an empirical analysis

10.1101/2020.06.11.20128074 ◽

2020 ◽

Cited By ~ 3

Author(s):

Wee Chian Koh ◽

Lin Naing ◽

Justin Wong

Keyword(s):

Reproduction Number ◽

Empirical Studies ◽

Viral Transmission ◽

International Travel ◽

Time Varying ◽

Epidemic Modelling ◽

Working From Home ◽

Modelling Studies ◽

The Impact ◽

At Home

AbstractBackgroundEpidemic modelling studies predict that physical distancing is critical in containing COVID-19. However, few empirical studies have validated this finding. Our study evaluates the effectiveness of different physical distancing measures in controlling viral transmission.MethodsWe identified three distinct physical distancing measures with varying intensity and implemented at different times—international travel controls, restrictions on mass gatherings, and lockdown-type measures—based on the Oxford COVID-19 Government Response Tracker. We also estimated the time-varying reproduction number (Rt) for 142 countries and tracked Rt temporally for two weeks following the 100th reported case in each country. We regressed Rt on the physical distancing measures and other control variables (income, population density, age structure, and temperature) and performed several robustness checks to validate our findings.FindingsComplete travel bans and all forms of lockdown-type measures have been effective in reducing average Rt over the 14 days following the 100th case. Recommended stay-at-home advisories and partial lockdowns are as effective as complete lockdowns in outbreak control. However, these measures have to be implemented early to be effective. Lockdown-type measures should be instituted two weeks before the 100th case and travel bans about a week before detection of the first case.InterpretationA combination of physical distancing measures, if implemented early, can be effective in containing COVID-19—tight border controls to limit importation of cases, encouraging physical distancing, moderately stringent measures such as working from home, and a full lockdown in the case of a probable uncontrolled outbreak.Research in contextEvidence before this studyEvidence on the impact of physical distancing measures on containing COVID-19 has primarily relied on epidemic modelling studies. As cases accumulate worldwide, it has become possible to use empirical data to validate the model-based findings. The few empirical studies that analyze global case data find that lockdowns and international travel restrictions are important, but have not explored, beyond these broad findings, the intensity and timeliness of the various measures to inform policymaking.Added value of this studyWe assessed, at a normalized stage of the epidemic curve, how the intensity and implementation timing of various physical distancing measures in 142 countries affect viral transmission, measured by the time-varying reproduction number (Rt). Other similar empirical studies treat the measures as binary variables, do not address the potential confounding effect of increased caseload on transmission, and do not use Rt as the primary metric.Implications of all the available evidenceOur results support the findings in modelling studies, and subsequent empirical studies, that physical distancing measures can limit disease spread. We found that full border control and complete lockdowns are effective, but less stringent measures such as stay-at-home recommendations and working from home are as effective. As such, the framing of lockdown measures as a binary approach may be counterproductive. Overall, these measures are only effective if they are implemented early.

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COVID-19 in South Korea

Postgraduate Medical Journal ◽

10.1136/postgradmedj-2020-137738 ◽

2020 ◽

Vol 96 (1137) ◽

pp. 399-402 ◽

Cited By ~ 6

Author(s):

Jun Yong Choi

Keyword(s):

Cardiovascular Disease ◽

Severe Acute Respiratory Syndrome ◽

South Korea ◽

Reproduction Number ◽

Current Situation ◽

School Closure ◽

Contact Tracing ◽

Major Contributor ◽

Novel Coronavirus ◽

Underlying Diseases

A novel coronavirus (severe acute respiratory syndrome-CoV-2) that initially originated from Wuhan, China, in December 2019 has already caused a pandemic. While this novel coronavirus disease (COVID-19) frequently induces mild diseases, it has also generated severe diseases among certain populations, including older-aged individuals with underlying diseases, such as cardiovascular disease and diabetes. As of 31 March 2020, a total of 9786 confirmed cases with COVID-19 have been reported in South Korea. South Korea has the highest diagnostic rate for COVID-19, which has been the major contributor in overcoming this outbreak. We are trying to reduce the reproduction number of COVID-19 to less than one and eventually succeed in controlling this outbreak using methods such as contact tracing, quarantine, testing, isolation, social distancing and school closure. This report aimed to describe the current situation of COVID-19 in South Korea and our response to this outbreak.

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Flattening the curve is not enough, we need to squash it: An explainer using a simple model

10.1101/2020.03.30.20048009 ◽

2020 ◽

Cited By ~ 1

Author(s):

ES McBryde ◽

MT Meehan ◽

JM Trauer

Keyword(s):

Deterministic Model ◽

Reproduction Number ◽

Herd Immunity ◽

International Travel ◽

Effective Control ◽

Curve Versus ◽

Successful Control ◽

The Difference ◽

The Uk ◽

Local Transmission

AbstractBackgroundAround the world there are examples of both effective control (e.g., South Korea, Japan) and less successful control (e.g., Italy, Spain, United States) of COVID-19 with dramatic differences in the consequent epidemic curves. Models agree that flattening the curve without controlling the epidemic completely is insufficient and will lead to an overwhelmed health service. A recent model, calibrated for the UK and US, demonstrated this starkly.MethodsWe used a simple compartmental deterministic model of COVID-19 transmission in Australia, to illustrate the dynamics resulting from shifting or flattening the curve versus completely squashing it.ResultsWe find that when the reproduction number is close to one, a small decrease in transmission leads to a large reduction in burden (i.e., cases, deaths and hospitalisations), but achieving this early in the epidemic through social distancing interventions also implies that the community will not reach herd immunity.ConclusionsAustralia needs not just to shift and flatten the curve, but to squash it by getting the reproduction number below one. This will require Australia to achieve transmission rates at least two thirds lower than those seen in the most severely affected countries.The knownCOVID-19 has been diagnosed in over 4,000 Australians. Up until mid-March, most were from international travel, but now we are seeing a rise in locally acquired cases.The newThis study uses a simple transmission dynamic model to demonstrate the difference between moderate changes to the reproduction number and forcing the reproduction number below one.The implicationsLowering local transmission is becoming important in reducing the transmission of COVID-19. To maintain control of the epidemic, the focus should be on those in the community who do not regard themselves as at risk.

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Mathematical modelling of COVID-19 transmission and control strategies in the population of Bauchi State, Nigeria

Annals of African Medical Research ◽

10.4081/aamr.2020.120 ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Yusuf Abdu Misau ◽

Nanshin Nansak ◽

Aliyu Maigoro ◽

Sani Malami ◽

Dominic Mogere ◽

...

Keyword(s):

Reproduction Number ◽

Control Strategies ◽

Research Work ◽

Control Measures ◽

High Rate ◽

World Health ◽

Contact Tracing ◽

Model Parameters ◽

Deterministic System ◽

The Novel

The novel SARS-COV-2 has since been declared a pandemic by the World Health Organization (WHO). The virus has spread from Wuhan city in China in December 2019 to no fewer than 200 countries as at June 2020 and still counting. Nigeria is currently experiencing a rapid spread of the virus amidst weak health system and more than 80% of population leaving on less than 1USD per day. To help understand the behavior of the virus in resource limited settings, we modelled the outbreak of COVID-19 and effects of control strategies in Bauchi state at north-eastern Nigeria. Using the real data of Bauchi state COVID-19 project, this research work extends the epidemic SEIR model by introducing new parameters based on the transmission dynamics of the novel COVID-19 pandemic and preventive measures. The total population of Bauchi State at the time of the study, given by is compartmentalized into five (5) different compartments as follows: Susceptible (S), Exposed (E), Infectious (I), Quarantined (Q) and Recovered (R). The new model is SEIQR. N = S → E → I → Q → R Data was collected by accessing Bauchi state electronic database of COVID-19 project to derive all the model parameters, while analysis and model building was done using Maple software. At the time of this study, it was found that the reproduction number R, for COVID-19 in Bauchi state, is 2.6 × 10-5. The reproduction number R decreased due to the application of control measures. The compartmental SEIRQ model in this study, which is a deterministic system of linear differential equations, has a continuum of disease-free equilibria, which is rigorously shown to be locallyasymptotically stable as the epidemiological threshold, known as the control reproduction number R= 0.0000026 is less than unity. The implication of this study is that the COVID-19 pandemic can be effectively controlled in Bauchi, since is R<1. Contact tracing and isolation must be increased as the models shows, the rise in infected class is a sign of high vulnerability of the population. Unless control measures are stepped up, despite high rate of recovery as shown by this study, infection rate will keep increasing as currently there is a no vaccine for COVID-19.

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Global lessons and Potential strategies in combating COVID-19 pandemic in Ethiopia: Systematic Review

10.1101/2020.05.23.20111062 ◽

2020 ◽

Author(s):

Yimam Getaneh ◽

Ajanaw Yizengaw ◽

Sisasy Adane ◽

Kidist Zealiyas ◽

Zelalem Abate ◽

...

Keyword(s):

Public Health ◽

Early Detection ◽

Public Awareness ◽

Rapid Test ◽

International Travel ◽

Mitigation Strategies ◽

World Health ◽

Contact Tracing ◽

Reference List ◽

Case Definitions

AbstractBackgroundCoronavirus disease 2019 (COVID-19) is a rapidly emerging disease that has been classified a pandemic by the World Health Organization (WHO). In the absence of treatment for this virus, there is an urgent need to find alternative public health strategies to control the spread. Here, we have conducted an online search for all relevant public health interventions for COVID-19. We then characterize and summarize the global COVID-19 pandemic situation and recommend potential mitigation strategies in the context of Ethiopia.MethodsInitial search of Pub Med central and Google scholar was undertaken followed by analysis of the text words; COVID-19,SARS-CoV-2, Global lessons and Pandemic; A second search using all identified keywords including COVID-19, Epidemiology, Sociocultural, Ethiopia; thirdly, the reference list of all identified reports and articles were searched. Accordingly, of the 1,402 articles, 39 were included in the analysis for this review.ResultCountries COVID-19 mitigation strategies widely varied. The most common global COVID-19 mitigation strategies include; whole of government approach including individual, community and environmental measures, detecting and isolating cases, contact tracing and quarantine, social and physical distancing measures including for mass gatherings and international travel measures. Models revealed that, social and physical distancing alone could prevent the pandemic from 60-95%, if timely and effectively implemented. Moreover, detecting and isolation of cases were found to be crucial while access to testing was found to the global challenge. Individual measures including proper hand washing were also reported to be effective measures in preventing the pandemic. Asymptomatic cases of COVID-19 ranged from 25% to 80% and as a result, countries are revising the case definition for early detection of mild symptomatic cases of COVID-19 with inclusion of Chills, Muscle pain and new loss of taste or smell in addition to Cough, Shortness of breath, Fever and Sore throat. Global reports also revealed that the incubation period of COVID-19 could go to 24 days. Ethiopia is also unique in the aspects of sociocultural prospects while more than 99.3% of the population has a religion. Moreover, 69% of the population is under the age of 29 years old and the health policy in the country focused on prevention and primary health care. All these could be potential entries and opportunities to combat COVID-19 pandemic in the context of Ethiopia.ConclusionWhile recommendations may change depending on the level of outbreak, we conclude that in Most countries have benefited from early interventions and in setups like Africa including Ethiopia where health system capability is limited, community engagement supported by local evidence with strict implementation of social and physical distancing measures is mandatory. Active involvement of religious Institutions and mobilizing youth could be entry to increase public awareness in mitigating COVID-19. Community level case detection could enhance early identification of cases which could be implemented through the health extension program. Isolation and quarantine beyond 14 days could help identify long term carriers of COVID-19. Validation and use of rapid test kits could be vital to increase access for testing. Revision of case definitions for COVID-19 could be important for early detection and identification of mild symptomatic cases.

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SARS-Cov-2 trajectory predictions and scenario simulations from a global perspective: a modelling study

Scientific Reports ◽

10.1038/s41598-020-75332-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tianan Yang ◽

Yexin Liu ◽

Wenhao Deng ◽

Weigang Zhao ◽

Jianwei Deng

Keyword(s):

Reproduction Number ◽

Human Mobility ◽

International Travel ◽

Global Perspective ◽

Transmission Model ◽

Social Distancing ◽

Global Epidemic ◽

Intervention Level ◽

Imported Cases ◽

Pharmaceutical Interventions

Abstract The coronavirus SARS-CoV-2 emerging from Wuhan, China has developed into a global epidemic. Here, we combine both human mobility and non-pharmaceutical interventions (social-distancing and suspected-cases isolation) into SEIR transmission model to understand how coronavirus transmits in a global environment. Dynamic trends of region-specific time-variant reproduction number, social-distancing rate, work-resumption rate, and suspected-cases isolation rate have been estimated and plotted for each region by fitting stochastic transmission processes to the real total confirmed cases reported of each region. We find after shutdown in Wuhan, the reproduction number in Wuhan greatly declined from 6·982 (95% CI 2·558–14·668) on January 23rd, 2020 to 1.130 (95% CI 0.289–3.279) on February 7th, 2020, and there was a higher intervention level in terms of social-distancing and suspected-cases isolation in Wuhan than the Chinese average and Western average, for the period from the shutdown in Wuhan to mid-March. Future epidemic trajectories of Western countries up to October 10th, 2020, have been predicted with 95% confidence intervals. Through the scenario simulation, we discover the benefits of earlier international travel ban and rigorous intervention strategies, and the significance of non-pharmaceutical interventions. From a global perspective, it is vital for each country to control the risks of imported cases, and execute rigorous non-pharmaceutical interventions before successful vaccination development.

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Reduction of Human Mobility Matters during Early COVID-19 Outbreaks: Evidence from India, Japan and China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18062826 ◽

2021 ◽

Vol 18 (6) ◽

pp. 2826

Author(s):

Zhehao Ren ◽

Ruiyun Li ◽

Tao Zhang ◽

Bin Chen ◽

Che Wang ◽

...

Keyword(s):

Human Mobility ◽

Critical Time ◽

Reproductive Number ◽

Time Varying ◽

Virus Spread ◽

Illness Onset ◽

Global Pandemic ◽

Imported Cases ◽

Local Transmission ◽

Japan And China

Mobility restrictions have been a heated topic during the global pandemic of coronavirus disease 2019 (COVID-19). However, multiple recent findings have verified its importance in blocking virus spread. Evidence on the association between mobility, cases imported from abroad and local medical resource supplies is limited. To reveal the association, this study quantified the importance of inter- and intra-country mobility in containing virus spread and avoiding hospitalizations during early stages of COVID-19 outbreaks in India, Japan, and China. We calculated the time-varying reproductive number (Rt) and duration from illness onset to diagnosis confirmation (Doc), to represent conditions of virus spread and hospital bed shortages, respectively. Results showed that inter-country mobility fluctuation could explain 80%, 35%, and 12% of the variance in imported cases and could prevent 20 million, 5 million, and 40 million imported cases in India, Japan and China, respectively. The critical time for screening and monitoring of imported cases is 2 weeks at minimum and 4 weeks at maximum, according to the time when the Pearson’s Rs between Rt and imported cases reaches a peak (>0.8). We also found that if local transmission is initiated, a 1% increase in intra-country mobility would result in 1430 (±501), 109 (±181), and 10 (±1) additional bed shortages, as estimated using the Doc in India, Japan, and China, respectively. Our findings provide vital reference for governments to tailor their pre-vaccination policies regarding mobility, especially during future epidemic waves of COVID-19 or similar severe epidemic outbreaks.

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Modeling COVID-19 Transmissions and Evaluation of Large Scale Social Restriction in Jakarta, Indonesia

10.1101/2020.10.30.20222984 ◽

2020 ◽

Author(s):

A. Hasan ◽

Y. Nasution ◽

H. Susanto ◽

E.R.M. Putri ◽

V.R. Tjahjono ◽

...

Keyword(s):

Quantitative Evaluation ◽

Large Scale ◽

Reproduction Number ◽

World Health ◽

Transmission Model ◽

Time Varying ◽

Short Term ◽

Social Restriction ◽

Short Term Forecasting ◽

Health Organization

AbstractThis paper presents mathematical modeling and quantitative evaluation of Large Scale Social Restriction (LSSR) in Jakarta between 10 April and 4 June 2020. The special capital region of Jakarta is the only province among 34 provinces in Indonesia with an average Testing Positivity Rate (TPR) below 5% recommended by the World Health Organization (WHO). The transmission model is based on a discrete-time compartmental epidemiological model incorporating suspected cases. The quantitative evaluation is measured based on the estimation of the time-varying effective reproduction number (ℛt). Our results show the LSSR has been successfully suppressed the spread of COVID-19 in Jakarta, which was indicated by ℛt < 1. However, once the LSSR was relaxed, the effective reproduction number increased significantly. The model is further used for short-term forecasting to mitigate the course of the pandemic.

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Global Lessons and Potential Strategies in Combating COVID-19 Pandemic in Ethiopia: Systematic Review

Clinical Oncology and Research ◽

10.31487/j.cor.2020.07.14 ◽

2020 ◽

pp. 1-7

Author(s):

Yimam Getaneh ◽

Ajanaw Yizengaw ◽

Sisasy Adane ◽

Kidist Zealiyas ◽

...

Keyword(s):

Early Detection ◽

Rapid Test ◽

Case Definition ◽

International Travel ◽

Mitigation Strategies ◽

World Health ◽

Contact Tracing ◽

Case Definitions ◽

Global Challenge ◽

Environmental Measures

Background: Coronavirus disease 2019 (CoVID-19) is a rapidly emerging disease that has been classified a pandemic by the World Health Organization (WHO). In the absence of treatment for this virus, there is an urgent need to find alternative public health strategies to control the spread. Here, we have conducted an online search and summarize the global COVID-19 pandemic situation and recommend potential mitigation strategies in the context of Ethiopia. Result: The most common global COVID-19 mitigation strategies include, whole of government approach including individual, community and environmental measures, detecting and isolating cases, contact tracing and quarantine, social and physical distancing measures including for mass gatherings and international travel measures. Social and physical distancing alone could prevent the pandemic from 60-95%. Moreover, detecting and isolation of cases were found to be crucial while access to testing was found to the global challenge. Individual measures including proper hand washing were also reported to be effective measures in preventing the pandemic. Asymptomatic cases of COVID-19 ranged from 25% to 80% and as a result, countries are revising the case definition for early detection of mild symptomatic cases of COVID-19 with inclusion of Chills, Muscle pain and new loss of taste or smell in addition to Cough, Shortness of breath, Fever and Sore throat. Ethiopia is also unique in the aspects of sociocultural prospects while more than 99.3% of the population has a religion. Moreover, 69% of the population is under the age of 29 years old and the health policy in the country focused on prevention and primary health care. Conclusion: While recommendations may change depending on the level of outbreak, we conclude that in most countries have benefited from early interventions and in setups like Africa including Ethiopia where health system capability is limited, community engagement supported by local evidence with strict implementation of social and physical distancing measures is mandatory. Community level case detection could enhance early identification of cases. Validation and use of rapid test kits could be vital to increase access for testing. Revision of case definitions for COVID-19 could be important for early detection of cases.

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Novel Coronavirus in Nigeria: Epidemiological analysis of the first 45 days of the pandemic

10.1101/2020.04.14.20064949 ◽

2020 ◽

Cited By ~ 1

Author(s):

Oyelola A. Adegboye ◽

Adeshina I. Adekunle ◽

Ezra Gayawan

Keyword(s):

Doubling Time ◽

Reproduction Number ◽

Infected Individual ◽

World Health ◽

Time Interval ◽

Epidemiological Analysis ◽

Serial Interval ◽

Novel Coronavirus ◽

Health Organization ◽

Local Transmission

AbstractBackgroundOn December 31, 2019, the World Health Organization (WHO) was notified of a novel coronavirus in China that was later named COVID-19. On March 11, 2020, the outbreak of COVID-19 was declared a pandemic. The first instance of the virus in Nigeria was documented on February 27, 2020.MethodsThis study provides a preliminary epidemiological analysis of the first 45 days of COVID-19 outbreak in Nigeria quantifying. We estimated the early transmissibility via time-varying reproduction number based on Bayesian method that incorporates uncertainty in the distribution of serial interval (time interval between symptoms onset in an infected individual and the infector) and adjusted for disease importation.FindingsBy April 11, 2020, 318 confirmed cases and 10 deaths from COVID-19 have occurred in Nigeria. At day 45, the exponential growth rate was 0.07 (95% Confidence Interval (CI): 0.05 – 0.10) with doubling time of 9.84 days (95% CI: 7.28 – 15.18). Separately for travel related and local cases the doubling time was 12.88 days and 2.86 days, respectively. Furthermore, we estimated the reproduction number for each day of the outbreak using three-weekly window while adjusting for travel related cases. The estimated reproduction number was 4.98 (95% CrI: 2.65 – 8.41) at day 22 (March 19, 2020), peaking at 5.61 (95% CrI: 3.83 –7.88) at day 25 (March 22, 2020). The median reproduction number over the study period was 2.71 and the latest value at April 11, 2020 was 1.42 (95% CI: 1.26 – 1.58).InterpretationThese 45-day estimates suggested that cases of COVID-19 in Nigeria have been remarkably lower than expected and the preparedness to detect needs to be shifted to stop local transmission.FundingNone

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