scholarly journals The effects of border control and quarantine measures on global spread of COVID-19

2020 ◽  
Author(s):  
M. Pear Hossain ◽  
Alvin Junus ◽  
Xiaolin Zhu ◽  
Pengfei Jia ◽  
Tzai-Hung Wen ◽  
...  
Keyword(s):  
Arrival Time ◽  
Control Measure ◽  
Control Measures ◽  
Rapid Expansion ◽  
Reproductive Number ◽  
Mathematical Framework ◽  
Border Control ◽  
Travel History ◽  
Global Spread ◽  
Imported Cases

AbstractThe rapid expansion of coronavirus (COVID-19) has been observed in many parts of the world. Many newly reported cases of this new coronavirus during early outbreak phases have been associated with travel history from an epidemic region (identified as imported cases). For those cases without travel history, the risk of wider spreads through community contact is even higher. However, most population models assume a homogeneous infected population without considering that the imported and secondary cases contracted by the imported cases can pose a different risk to community spread.We have developed an “easy-to-use” mathematical framework extending from a meta-population model embedding city-to-city connections to stratify the dynamics of transmission waves caused by imported, secondary, and others from an outbreak source region when control measures are considered. Using the dynamics of the secondary cases, we are able to determine the probability of community spread.Using the top 10 visiting cities from Wuhan in China as an example, we first demonstrated that the arrival time and the dynamics of the outbreaks at these cities can be successfully predicted under the reproductive number R0 = 2.92 and latent period τ = 5.2 days. Next, we showed that although control measures can gain extra 32.5 and 44.0 days in arrival time through a high intensive border control measure and a shorter time to quarantine under a low R0 (1.4), if the R0 is higher (2.92), only 10 extra days can be gained for each of the same measures. This suggests the importance of lowering the incidence at source regions together with infectious disease control measures in susceptible regions. The study allows us to assess the effects of border control and quarantine measures on the emergence and the global spread in a fully connected world using the dynamics of the secondary cases.

scholarly journals Estimating the risk on outbreak spreading of 2019-nCoV in China using transportation data

2020 ◽  
Author(s):  
Hsiang-Yu Yuan ◽  
M. Pear Hossain ◽  
Mesfin Tsegaye ◽  
Xiaolin Zhu ◽  
Pengfei Jia ◽  
...  
Keyword(s):  
Arrival Time ◽  
Critical Time ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Mathematical Framework ◽  
Cumulative Number ◽  
Border Control ◽  
Imported Cases ◽  
Novel Virus

AbstractA novel corona virus (2019-nCoV) was identified in Wuhan, China and has been causing an unprecedented outbreak in China. The spread of this novel virus can eventually become an international emergency. During the early outbreak phase in Wuhan, one of the most important public health tasks is to prevent the spread of the virus to other cities. Therefore, full-scale border control measures to prevent the spread of virus have been discussed in many nearby countries. At the same time, lockdown in Wuhan cityu (border control from leaving out) has been imposed. The challenge is that many people have traveled from Wuhan to other cities before the border control. Thus, it is difficult to forecast the number of imported cases at different cities and estimate their risk on outbreak emergence.Here, we have developed a mathematical framework incorporating city-to-city connections to calculate the number of imported cases of the novel virus from an outbreak source, and the cumulative number of secondary cases generated by the imported cases. We used this number to estimate the arrival time of outbreak emergence using air travel frequency data from Wuhan to other cities, collected from the International Air Transport Association database. In addition, a meta-population compartmental model was built based on a classical SIR approach to simulate outbreaks at different cities.We consider the scenarios under three basic reproductive number (R0) settings using the best knowledge of the current findings, from high (2.92), mild (1.68), to a much lower numbers (1.4). The mean arrival time of outbreak spreading has been determined. Under the high R0, the critical time is 17.9 days after December 31, 2019 for outbreak spreading. Under the low R0, the critical time is between day 26.2 to day 35 after December 31, 2019. To make an extra 30 days gain, under the low R0 (1.4), the control measures have to reduce 87% of the connections between the source and target cities. Under the higher R0 (2.92), the effect on reducing the chance of outbreak emergence is generally low until the border control measure was enhanced to reduce more than 95% of the connections.

scholarly journals Risk Assessment of Novel Coronavirus COVID-19 Outbreaks Outside China

2020 ◽  
Vol 9 (2) ◽  
pp. 571 ◽  
Author(s):  
Péter Boldog ◽  
Tamás Tekeli ◽  
Zsolt Vizi ◽  
Attila Dénes ◽  
Ferenc A. Bartha ◽  
...  
Keyword(s):  
Control Measure ◽  
Mainland China ◽  
Destination Country ◽  
Control Measures ◽  
Cumulative Number ◽  
Travel Restrictions ◽  
Imported Cases ◽  
Major Outbreak ◽  
Novel Coronavirus ◽  
Local Reproduction

We developed a computational tool to assess the risks of novel coronavirus outbreaks outside of China. We estimate the dependence of the risk of a major outbreak in a country from imported cases on key parameters such as: (i) the evolution of the cumulative number of cases in mainland China outside the closed areas; (ii) the connectivity of the destination country with China, including baseline travel frequencies, the effect of travel restrictions, and the efficacy of entry screening at destination; and (iii) the efficacy of control measures in the destination country (expressed by the local reproduction number R loc ). We found that in countries with low connectivity to China but with relatively high R loc , the most beneficial control measure to reduce the risk of outbreaks is a further reduction in their importation number either by entry screening or travel restrictions. Countries with high connectivity but low R loc benefit the most from policies that further reduce R loc . Countries in the middle should consider a combination of such policies. Risk assessments were illustrated for selected groups of countries from America, Asia, and Europe. We investigated how their risks depend on those parameters, and how the risk is increasing in time as the number of cases in China is growing.

scholarly journals Analysis of Imported Cases of COVID-19 in Taiwan: A Nationwide Study

2020 ◽  
Vol 17 (9) ◽  
pp. 3311 ◽  
Author(s):  
Jui-Yao Liu ◽  
Tzeng-Ji Chen ◽  
Shinn-Jang Hwang
Keyword(s):  
Control Measures ◽  
Contact Tracing ◽  
Border Control ◽  
Symptom Presentation ◽  
Symptom Screening ◽  
Imported Cases ◽  
Infection Source ◽  
Community Transmission ◽  
Strict Enforcement ◽  
Novel Coronavirus

In the early stages of the 2019 novel coronavirus disease (COVID-19) pandemic, containment of disease importation from epidemic areas was essential for outbreak control. This study is based on publicly accessible data on confirmed COVID-19 cases in Taiwan extracted from the Taiwan Centers for Disease Control website. We analysed the characteristics, infection source, symptom presentation, and route of identification of the 321 imported cases that were identified from 21 January to 6 April 2020. They were mostly returned Taiwanese citizens who had travelled to one or more of 37 countries for tourism, business, work, or study. Half of these cases developed symptoms before arrival, most of the remainder developed symptoms 1–13 days (mean 4.0 days) after arrival, and 3.4% never developed symptoms. Three-quarters of the cases had respiratory symptoms, 44.9% had fever, 13.1% lost smell or taste, and 7.2% had diarrhoea. Body temperature and symptom screening at airports identified 32.7% of the cases. Of the remainder, 27.7% were identified during home quarantining, 16.2% were identified via contact tracing, and 23.4% were reported by hospitals. Under the strict enforcement of these measures, the incidence of locally acquired COVID-19 cases in Taiwan remains sporadic. In conclusion, proactive border control measures are effective for preventing community transmission of this disease.

scholarly journals Impact of international travel and border control measures on the global spread of the novel 2019 coronavirus outbreak

2020 ◽  
Vol 117 (13) ◽  
pp. 7504-7509 ◽  
Author(s):  
Chad R. Wells ◽  
Pratha Sah ◽  
Seyed M. Moghadas ◽  
Abhishek Pandey ◽  
Affan Shoukat ◽  
...  
Keyword(s):  
Mainland China ◽  
International Travel ◽  
Control Measures ◽  
Chinese Government ◽  
Border Control ◽  
The Novel ◽  
Public Health Response ◽  
Global Spread ◽  
Travel Restrictions ◽  
The Impact

The novel coronavirus outbreak (COVID-19) in mainland China has rapidly spread across the globe. Within 2 mo since the outbreak was first reported on December 31, 2019, a total of 566 Severe Acute Respiratory Syndrome (SARS CoV-2) cases have been confirmed in 26 other countries. Travel restrictions and border control measures have been enforced in China and other countries to limit the spread of the outbreak. We estimate the impact of these control measures and investigate the role of the airport travel network on the global spread of the COVID-19 outbreak. Our results show that the daily risk of exporting at least a single SARS CoV-2 case from mainland China via international travel exceeded 95% on January 13, 2020. We found that 779 cases (95% CI: 632 to 967) would have been exported by February 15, 2020 without any border or travel restrictions and that the travel lockdowns enforced by the Chinese government averted 70.5% (95% CI: 68.8 to 72.0%) of these cases. In addition, during the first three and a half weeks of implementation, the travel restrictions decreased the daily rate of exportation by 81.3% (95% CI: 80.5 to 82.1%), on average. At this early stage of the epidemic, reduction in the rate of exportation could delay the importation of cases into cities unaffected by the COVID-19 outbreak, buying time to coordinate an appropriate public health response.

scholarly journals An integrative review of the limited evidence on international travel bans as an emerging infectious disease disaster control measure

2020 ◽  
Vol 18 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Nicole A. Errett, PhD, MSPH ◽  
Lauren M. Sauer, MS ◽  
Lainie Rutkow, PhD, JD, MPH
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
Control Measure ◽  
Middle Eastern ◽  
Emerging Infectious Diseases ◽  
Geographic Region ◽  
International Travel ◽  
Control Measures ◽  
Integrative Review ◽  
Global Spread

In our increasingly interconnected world, the potential for emerging infectious diseases (EIDs) to spread globally is of paramount concern. Travel bans—herein defined as the complete restriction of travel from at least one geographic region to at least one other international geographic region—are a potential policy solution to control the global spread of disease. The social, economic, and health-related consequences of travel bans, as well as the available evidence on the effectiveness of travel restrictions in preventing the global spread of influenza, have been previously described. However, the effectiveness of travel bans in reducing the spread of noninfluenza EIDs, characterized by different rates and modes of transmission, is less well understood. This study employs an integrative review approach to summarize the minimal evidence on effectiveness of travel bans to decrease the spread of severe acute respiratory syndrome (SARS), Middle Eastern respiratory syndrome (MERS), Ebola virus disease (EVD), and Zika virus disease (ZVD). We describe and qualify the evidence presented in six modeling studies that assess the effectiveness of travel bans in controlling these noninfluenza EID events. We conclude that there is an urgent need for additional research to inform policy decisions on the use of travel bans and other control measures to control  oninfluenza EIDs in advance of the next outbreak.

scholarly journals Shigellosis Dynamics: Modelling the Effects of Treatment, Sanitation, and Education in the Presence of Carriers

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Stephen Edward ◽  
Eunice Mureithi ◽  
Nyimvua Shaban
Keyword(s):  
Potential Role ◽  
Control Strategies ◽  
Control Measure ◽  
Control Measures ◽  
Reproductive Number ◽  
Direct Transmission ◽  
Multiple Control ◽  
Globally Asymptotically Stable ◽  
Indirect Transmission ◽  
Dynamics Modelling

A mathematical model for Shigellosis including disease carriers with multiple control strategies is developed. We compute the effective reproductive number Re, which is used to analyze the local stability of the equilibria, while the comparison theorem is used to prove global stability. By constructing a suitable Lyapunov function, the model endemic equilibrium is globally asymptotically stable when Re>1. Sensitivity analysis is performed to investigate the parameters that have a high impact on the transmission dynamics of the disease with direct transmission contributing more infections than indirect transmission. The effects of control measures are then investigated both analytically and numerically. Numerical results show that there is a reduction in the number of infections when at least a single control measure is applied efficiently. However, as the number of control interventions increases, Shigellosis elimination is more possible. Results also show that carriers play a potential role in the prevalence of Shigellosis and ignoring these individuals could potentially undermine the efforts of containing this epidemic.

scholarly journals Risk Assessment of Novel Coronavirus COVID-19 Outbreaks Outside China

2020 ◽  
Author(s):  
Péter Boldog ◽  
Tamás Tekeli ◽  
Zsolt Vizi ◽  
Attila Dénes ◽  
Ferenc A. Bartha ◽  
...  
Keyword(s):  
Control Measure ◽  
Mainland China ◽  
Destination Country ◽  
Control Measures ◽  
Cumulative Number ◽  
Travel Restrictions ◽  
Imported Cases ◽  
Major Outbreak ◽  
Novel Coronavirus ◽  
Local Reproduction

AbstractWe developed a computational tool to assess the risks of novel coronavirus outbreaks outside of China. We estimate the dependence of the risk of a major outbreak in a country from imported cases on key parameters such as: (i) the evolution of the cumulative number of cases in mainland China outside the closed areas; (ii) the connectivity of the destination country with China, including baseline travel frequencies, the effect of travel restrictions, and the efficacy of entry screening at destination; and (iii) the efficacy of control measures in the destination country (expressed by the local reproduction number Rloc). We found that in countries with low connectivity to China but with relatively high Rloc, the most beneficial control measure to reduce the risk of outbreaks is a further reduction in their importation number either by entry screening or travel restrictions. Countries with high connectivity but low Rloc benefit the most from policies that further reduce Rloc. Countries in the middle should consider a combination of such policies. Risk assessments were illustrated for selected groups of countries from America, Asia, and Europe. We investigated how their risks depend on those parameters, and how the risk is increasing in time as the number of cases in China is growing.

scholarly journals Effectiveness of quarantine measure on transmission dynamics of COVID-19 in Hong Kong

2020 ◽  
Author(s):  
Hsiang-Yu Yuan ◽  
Axiu Mao ◽  
Guiyuan Han ◽  
Hsiangkuo Yuan ◽  
Dirk Pfeiffer
Keyword(s):  
Hong Kong ◽  
Symptom Onset ◽  
Mainland China ◽  
Economic Loss ◽  
Control Measures ◽  
Rapid Expansion ◽  
Transmission Dynamics ◽  
Reproductive Number ◽  
Suspected Case ◽  
Infected Case

AbstractThe rapid expansion of COVID-19 has caused a global pandemic. Although quarantine measures have been used widely, the critical steps among them to suppress the outbreak without a huge social-economic loss remain unknown. Hong Kong, unlike other regions in the world, had a massive number of travellers from Mainland China during the early expansion period, and yet the spread of virus has been relatively limited. Understanding the effect of control measures to reduce the transmission in Hong Kong can improve the control of the virus spreading.We have developed a susceptible-exposed-infectious-quarantined-recovered (SEIQR) meta-population model that can stratify the infections into imported and subsequent local infections, and therefore to obtain the control effects on transmissibility in a region with many imported cases. We fitted the model to both imported and local confirmed cases with symptom onset from 18 January to 29 February 2020 in Hong Kong with daily transportation data and the transmission dynamics from Wuhan and Mainland China.The model estimated that the reproductive number was dropped from 2.32 to 0.76 (95% CI, 0.66 to 0.86) after an infected case was estimated to be quarantined half day before the symptom onset, corresponding to the incubation time of 5.43 days (95% CI, 1.30-9.47). If the quarantine happened about one day after the onset, community spread would be likely to occur, indicated by the reproductive number larger than one. The results suggest that the early quarantine for a suspected case before the symptom onset is a key factor to suppress COVID-19.

scholarly journals On the Optimal Control of a Malware Propagation Model

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1518
Author(s):  
Jose Diamantino Hernández Guillén ◽  
Ángel Martín del Rey ◽  
Roberto Casado Vara
Keyword(s):  
Optimal Control ◽  
Control Measure ◽  
Propagation Model ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Security Measures ◽  
Epidemic Process ◽  
Malware Propagation ◽  
Prevention Measure

An important way considered to control malware epidemic processes is to take into account security measures that are associated to the systems of ordinary differential equations that governs the dynamics of such systems. We can observe two types of control measures: the analysis of the basic reproductive number and the study of control measure functions. The first one is taken at the beginning of the epidemic process and, therefore, we can consider this to be a prevention measure. The second one is taken during the epidemic process. In this work, we use the theory of optimal control that is associated to systems of ordinary equations in order to find a new function to control malware epidemic through time. Specifically, this approach is evaluate on a particular compartmental malware model that considers carrier devices.

scholarly journals Accounting for imported cases in estimating the time-varying reproductive number of COVID-19

2021 ◽  
Author(s):  
Tim K. Tsang ◽  
Peng Wu ◽  
Eric H. Y. Lau ◽  
Benjamin J. Cowling
Keyword(s):  
Public Health ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Reproductive Number ◽  
Considerable Proportion ◽  
Time Varying ◽  
Health Measures ◽  
Imported Cases ◽  
The Impact ◽  
Local Transmission

ABSTRACTBackgroundEstimating the time-varying reproductive number, Rt, is critical for monitoring transmissibility of an emerging infectious disease during outbreaks. When local transmission is effectively suppressed, imported cases could substantially impact transmission dynamics.MethodsWe developed methodology to estimate separately the Rt for local cases and imported cases, since certain public health measures aim only to reduce onwards transmission from imported cases. We applied the framework to data on COVID-19 outbreaks in Hong Kong.ResultsWe estimated that the Rt for local cases decreased from above one in the early phase of outbreak to below one after tightening of public health measures. Assuming the same infectiousness of local and imported cases underestimated Rt for local cases due to control measures targeting travelers.ConclusionsWhen a considerable proportion of all cases are imported, the impact of imported cases in estimating Rt is critical. The methodology described here can allow for differential infectiousness of local imported cases.

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