scholarly journals Modeling of suppression and mitigation interventions in the COVID-19 epidemics

2021 ◽  
Author(s):  
YueXing Han ◽  
ZeYang Xie ◽  
YiKe Guo ◽  
Bing Wang
Keyword(s):  
Intervention Strategy ◽  
Periodic Wave ◽  
Periodic Waves ◽  
Infection Level ◽  
Medical Resources ◽  
Daily Lives ◽  
Epidemic Dynamics ◽  
Intervention Measures ◽  
Negative Impacts ◽  
Short Time

Abstract Background: The global spread of the COVID-19 pandemic has become the most fundamental threat to humanealth. In the absence of vaccines and effective therapeutical solutions, non-pharmaceutic interventions have become a major way for controlling the epidemics. Soft mitigation interventions are able to slow down the epidemic but not to halt it well. While strict suppression interventions are efficient for controlling the epidemics, long-term measures are likely to have negative impacts on economics and people’s daily lives. Hence, dynamically balancing the interventions of suppression and mitigation plays a fundamental role in manipulating the epidemic curves.Methods: We collected data of the number of infections for several countries during the COVID-19 pandemics and found a clear phenomenon of periodic waves of infections. Based on the observation, by connecting the infection level with the medical resources and a tolerance parameter, we propose a mathematical model by combining intervention measures to understand the epidemic dynamics.Results: Depending on the parameters of the medical resources, tolerance level, and the starting time of interventions, the combined intervention measure dynamically changes with the infection level, resulting in a periodic wave of infections con-trolled within an accepted level. The study reveals that, (a) with an immediate, strict suppression, the number of infections and deaths is well controlled with a significant reduction in very short time period; (b) an appropriate, dynamical combination of suppression and mitigation may find a feasible way in reducing the impacts of epidemics on people’s lives and economics.Conclusions: While the assumption of interventions deployed with a cycle of period in the model is limited and unrealistic, the phenomenon of periodic waves of infections in reality is captured by our model. These results provide helpful insights for policy-makers to dynamically deploy an appropriate intervention strategy to effectively battle against the COVID-19.

scholarly journals Modeling of suppression and mitigation interventions in the COVID-19 epidemics

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuexing Han ◽  
Zeyang Xie ◽  
Yike Guo ◽  
Bing Wang
Keyword(s):  
Intervention Strategy ◽  
Periodic Wave ◽  
Periodic Waves ◽  
Infection Level ◽  
Medical Resources ◽  
Epidemic Curve ◽  
Epidemic Dynamics ◽  
Intervention Measures ◽  
Negative Impacts ◽  
Short Time

Abstract Background The global spread of the COVID-19 pandemic has become the most fundamental threat to human health. In the absence of vaccines and effective therapeutical solutions, non-pharmaceutic intervention has become a major way for controlling the epidemic. Gentle mitigation interventions are able to slow down the epidemic but not to halt it well. While strict suppression interventions are efficient for controlling the epidemic, long-term measures are likely to have negative impacts on economics and people’s daily live. Hence, dynamically balancing suppression and mitigation interventions plays a fundamental role in manipulating the epidemic curve. Methods We collected data of the number of infections for several countries during the COVID-19 pandemics and found a clear phenomenon of periodic waves of infection. Based on the observation, by connecting the infection level with the medical resources and a tolerance parameter, we propose a mathematical model to understand impacts of combining intervention measures on the epidemic dynamics. Results Depending on the parameters of the medical resources, tolerance level, and the starting time of interventions, the combined intervention measure dynamically changes with the infection level, resulting in a periodic wave of infections controlled below an accepted level. The study reveals that, (a) with an immediate, strict suppression, the numbers of infections and deaths are well controlled with a significant reduction in a very short time period; (b) an appropriate, dynamical combination of suppression and mitigation may find a feasible way in reducing the impacts of epidemic on people’s live and economics. Conclusions While the assumption of interventions deployed with a cycle of period in the model is limited and unrealistic, the phenomenon of periodic waves of infections in reality is captured by our model. These results provide helpful insights for policy-makers to dynamically deploy an appropriate intervention strategy to effectively battle against the COVID-19.

scholarly journals Role of suppression and mitigation interventions in controlling the COVID-19 epidemics

2020 ◽  
Author(s):  
YueXing Han ◽  
Bing Wang ◽  
YiKe Guo
Keyword(s):  
Intervention Strategy ◽  
Periodic Wave ◽  
Mitigation Strategy ◽  
Negative Effects ◽  
Infection Level ◽  
Daily Lives ◽  
Low Level ◽  
Epidemic Dynamics ◽  
Negative Effect ◽  
Combined Intervention

Abstract Background: The global spread of the COVID-19 pandemic has become the most fundamental threat to human lives. In the absence of vaccines and effective therapeutical solutions, non-pharmaceutic interventions have been a major way to control the epidemics. Relaxed mitigation interventions can slow down the epidemics but cannot control it well, while strict suppression interventions can efficiently halt the spread of epidemics, bringing negative effects on economics and people’s daily lives. Hence, suppression strategy and mitigation strategy play different roles in manupulating the epidemic curves.Methods: Here, we propose a mathematical model to understand the rols of suppression and mitigation in changing the epidemic dynamics. By connecting the infection level with the consideration of the medical resources and a tolerence parameter, a combined intervention strategy of suppression and mitigation is proposed. Results: The combined intervention strategy is able to adaptively change with the infection level, resulting in a periodic wave of controlled infections. Depending on the tolerance level, the mitigation strategy can be adaptively switched on or off. The combined intervention can efficiently reduce the numbers of deaths and confirmed cases, and keep the infection within a low level, while such a wave of infection may exist for a long time before the availability of vaccines.Conclusion: In order to control the epidemics, policy-makers have to consider the issues of human lives and economics. To solve such a dilemma, we propose a combined intervention stategy of suppression and mitigation, which can adaptively alternate with the epidemic dynamics. The combined strategy of suppression and mitigation is able to effectively control the epidemics within a low level, it can also reduce the negative effect on economics and human’s normal lives.

scholarly journals Will the Large-scale Vaccination Succeed in Containing the COVID-19 Epidemic and How Soon?

2021 ◽  
Author(s):  
Shilei Zhao ◽  
Tong Sha ◽  
Yongbiao Xue ◽  
Chung-I Wu ◽  
Hua Chen
Keyword(s):  
United States Of America ◽  
Vaccine Efficacy ◽  
Large Scale ◽  
Herd Immunity ◽  
Vaccination Rate ◽  
Epidemic Dynamics ◽  
Intervention Measures ◽  
Vaccination Scheme ◽  
Mutant Strains ◽  
Promising Solution

The availability of vaccines provides a promising solution to containing the COVID-19 pandemic. Here, we develop an epidemiological model to quantitatively analyze and predict the epidemic dynamics of COVID-19 under vaccination. The model is applied to the daily released numbers of confirmed cases of Israel and United States of America to explore and predict the trend under vaccination based on their current epidemic status and intervention measures. For Israel, of which 53.83% of the population was fully vaccinated, under the current intensity of NPIs and vaccination scheme, the pandemic is predicted to end between May 14, 2021 to May 16, 2021 depending on an immunity duration between 180 days and 365 days; Assuming no NPIs after March 24, 2021, the pandemic will ends later, between July 4, 2021 to August 26, 2021. For USA, if we assume the current vaccination rate (0.268% per day) and intensity of NPIs, the pandemic will end between February 3, 2022 and August 17, 2029 depending on an immunity duration between 180 days and 365 days. However, assuming an immunity duration of 180 days and with no NPIs, the pandemic will not end, and instead reach an equilibrium state with a proportion of the population remaining actively infected. Overall the daily vaccination rate should be chosen according to the vaccine efficacy and the immunity duration to achieve herd immunity. In some situations, vaccination alone cannot stop the pandemic, and NPIs are necessary both to supplement vaccination and accelerate the end of the pandemic. Considering that vaccine efficacy and duration of immunity may be reduced for new mutant strains, it is necessary to remain cautiously optimistic about the prospect of the pandemic under vaccination.

Dynamical Behavior of Supernonlinear Positron-Acoustic Periodic Waves and Chaos in Nonextensive Electron-Positron-Ion Plasmas

2019 ◽  
Vol 74 (6) ◽  
pp. 499-511 ◽  
Author(s):  
Jharna Tamang ◽  
Asit Saha
Keyword(s):  
Periodic Orbit ◽  
Homoclinic Orbit ◽  
Dynamical Behavior ◽  
Periodic Wave ◽  
Phase Portraits ◽  
Periodic Waves ◽  
Periodic Force ◽  
Positive Ions ◽  
Qualitative Approaches ◽  
Electron Positron

AbstractPropagation of nonlinear and supernonlinear positron-acoustic periodic waves is examined in an electron-positron-ion plasma composed of static positive ions, mobile cold positrons, and q-nonextensive electrons and hot positrons. Employing the phase plane theory of planar dynamical systems, all qualitatively different phase portraits that include nonlinear positron-acoustic homoclinic orbit, nonlinear positron-acoustic periodic orbit, supernonlinear positron-acoustic homoclinic orbit, and supernonlinear positron-acoustic periodic orbit are demonstrated subjected to the parameters $q,{\mu_{1}},{\mu_{2}},{\sigma_{1}},{\sigma_{2}}$, and V. The nonlinear and supernonlinear positron-acoustic periodic wave solutions are reported for different situations through numerical computations. It is observed that the nonextensive parameter (q) acts as a controlling parameter in the dynamic motion of nonlinear and supernonlinear positron-acoustic periodic waves. The dynamic motions for the positron-acoustic traveling waves with the influence of an extrinsic periodic force are investigated through distinct qualitative approaches, such as phase portrait analysis, sensitivity analysis, time series analysis, and Poincaré section. The results of this paper may be applicable in understanding nonlinear, supernonlinear positron-acoustic periodic waves, and their chaotic motion in space plasma environments.

scholarly journals Coronavirus and Halal Tourism and Hospitality Industry: Is It a Journey to the Unknown?

2020 ◽  
Vol 12 (21) ◽  
pp. 9260 ◽  
Author(s):  
Hatem El-Gohary
Keyword(s):  
Global Economy ◽  
Hospitality Industry ◽  
Well Being ◽  
Tourism Industry ◽  
Research Papers ◽  
Negative Impacts ◽  
Travel Industry ◽  
Tourism And Hospitality Industry ◽  
Tourism And Hospitality ◽  
Short Time

Coronavirus (COVID-19) gained and will continue to gain a lot of global attention over the coming months (and maybe the coming few years). Since its outbreak in Wuhan (China), it has turned into one of the major challenges affecting the whole world. In a comparatively short time, the virus outbreak turned into a pandemic that led to massive negative impacts not only on people health and well-being, but also on the global economy, travel industry, pharmaceutical industry, tourism industry, and many other industries. This research paper aims to investigate the different effects of coronavirus on the global Halal tourism and Halal hospitality industry and whether the coronavirus pandemic is the end of Halal tourism and hospitality as we know it or not. The paper offers an in-depth theoretical examination of the different aspect of the pandemic on Halal tourism and hospitality industry and provides guidance on how to address these different aspects. The current paper is one of very few research papers addressing coronavirus on the tourism and hospitality industry.

scholarly journals Networks and epidemic models

2005 ◽  
Vol 2 (4) ◽  
pp. 295-307 ◽  
Author(s):  
Matt J Keeling ◽  
Ken T.D Eames
Keyword(s):  
Network Theory ◽  
Disease Dynamics ◽  
Approximation Techniques ◽  
Individual Level ◽  
Epidemic Dynamics ◽  
Intervention Measures ◽  
The Social ◽  
Finite Set ◽  
Random Mixing ◽  
The Individual

Networks and the epidemiology of directly transmitted infectious diseases are fundamentally linked. The foundations of epidemiology and early epidemiological models were based on population wide random-mixing, but in practice each individual has a finite set of contacts to whom they can pass infection; the ensemble of all such contacts forms a ‘mixing network’. Knowledge of the structure of the network allows models to compute the epidemic dynamics at the population scale from the individual-level behaviour of infections. Therefore, characteristics of mixing networks—and how these deviate from the random-mixing norm—have become important applied concerns that may enhance the understanding and prediction of epidemic patterns and intervention measures. Here, we review the basis of epidemiological theory (based on random-mixing models) and network theory (based on work from the social sciences and graph theory). We then describe a variety of methods that allow the mixing network, or an approximation to the network, to be ascertained. It is often the case that time and resources limit our ability to accurately find all connections within a network, and hence a generic understanding of the relationship between network structure and disease dynamics is needed. Therefore, we review some of the variety of idealized network types and approximation techniques that have been utilized to elucidate this link. Finally, we look to the future to suggest how the two fields of network theory and epidemiological modelling can deliver an improved understanding of disease dynamics and better public health through effective disease control.

scholarly journals Numerical calculation of N -periodic wave solutions to coupled KdV–Toda-type equations

2021 ◽  
Vol 477 (2245) ◽  
pp. 20200752
Author(s):  
Yingnan Zhang ◽  
Xingbiao Hu ◽  
Jianqing Sun
Keyword(s):  
Toda Lattice ◽  
Kdv Equation ◽  
Direct Method ◽  
Periodic Wave ◽  
Periodic Waves ◽  
Periodic Wave Solutions ◽  
Wave Solutions ◽  
Numerical Process ◽  
Relativistic Toda Lattice ◽  
Ito Equation

In this paper, we study the N -periodic wave solutions of coupled Korteweg–de Vries (KdV)–Toda-type equations. We present a numerical process to calculate the N -periodic waves based on the direct method of calculating periodic wave solutions proposed by Akira Nakamura. Particularly, in the case of N  = 3, we give some detailed examples to show the N -periodic wave solutions to the coupled Ramani equation, the Hirota–Satsuma coupled KdV equation, the coupled Ito equation, the Blaszak–Marciniak lattice, the semi-discrete KdV equation, the Leznov lattice and a relativistic Toda lattice.

scholarly journals THE EFFECT OF DAILY LIFE TRACES DUE TO CULTURAL CHANGE ON FIKRET MUALLA'S ART

2021 ◽  
Vol 10 (86) ◽  
Keyword(s):  
Cultural Change ◽  
Social Life ◽  
Cultural Difference ◽  
Daily Life ◽  
Relevant Literature ◽  
Human Beings ◽  
Daily Lives ◽  
The People ◽  
The Social ◽  
Short Time

Culture is the values that constitute the unity of life, thought and belief that a society creates in the historical and social development process. These values, which determine the lifestyle of a nation, people and society, have been passed down from generation to generation. The unique life models, art, morality, laws and order of the society determine the culture of that society and shape the daily lives of the people who make up the society. When the social structure and life of different nations are examined, it is noteworthy that the cultures differ significantly and diverge from each other. While human beings adapt to all kinds of changes with the instinct of survival, they consciously or unconsciously keep pace with their social life in order to continue their social life within the changing cultural structure. Fikret Mualla, a Turkish painter, was born in 1903, until his mid-thirties naturally lived and produced works by being influenced by Turkish culture and society. Although he went abroad for a short time many times during this period, he went to Paris in 1939 and lived there for twenty-six years. During this long period, his art, like himself, was influenced by the culture he lived in, and he reflected the daily life in Paris and artistic expression forms on his works. Cafes, circuses and streets in Paris have become the main subject of the artist's works. To analyze the effects of contemporary life in the context of cultural change through artists and works of art; It is aimed to contribute to the relevant literature by examining the changes brought by the French culture and life in Fikret Mualla's works. In addition, it is aimed to examine how the cultural difference affects the works of the artist in question in terms of subject and technique. Qualitative research methods and techniques were used in the study in which general scanning model was used. Keywords: Culture, Turkish Art, Fikret Mualla

scholarly journals The ecological dynamics of the coronavirus epidemics during transmission from outside sources when R 0 is successfully managed below one

2021 ◽  
Vol 8 (6) ◽  
pp. 202234
Author(s):  
Steinar Engen ◽  
Huaiyu Tian ◽  
Ruifu Yang ◽  
Ottar N. Bjørnstad ◽  
Jason D. Whittington ◽  
...  
Keyword(s):  
World Health ◽  
Reproductive Number ◽  
Model Framework ◽  
Epidemic Dynamics ◽  
Intervention Measures ◽  
Individual Based Models ◽  
Rapid Prediction ◽  
Asymptomatic Infections ◽  
Age Structured ◽  
Health Organization

Since COVID-19 spread globally in early 2020 and was declared a pandemic by the World Health Organization (WHO) in March, many countries are managing the local epidemics effectively through intervention measures that limit transmission. The challenges of immigration of new infections into regions and asymptomatic infections remain. Standard deterministic compartmental models are inappropriate for sub- or peri-critical epidemics (reproductive number close to or less than one), so individual-based models are often used by simulating transmission from an infected person to others. However, to be realistic, these models require a large number of parameters, each with its own set of uncertainties and lack of analytic tractability. Here, we apply stochastic age-structured Leslie theory with a long history in ecological research to provide some new insights to epidemic dynamics fuelled by external imports. We model the dynamics of an epidemic when R 0 is below one, representing COVID-19 transmission following the successful application of intervention measures, and the transmission dynamics expected when infections migrate into a region. The model framework allows more rapid prediction of the shape and size of an epidemic to improve scaling of the response. During an epidemic when the numbers of infected individuals are rapidly changing, this will help clarify the situation of the pandemic and guide faster and more effective intervention.

scholarly journals COVID-19 pandemic control: balancing detection policy and lockdown intervention under ICU sustainability

2020 ◽  
Author(s):  
Arthur Charpentier ◽  
Romuald Elie ◽  
Mathieu Laurière ◽  
Viet Chi Tran
Keyword(s):  
Social Interactions ◽  
Optimal Strategies ◽  
Economic Cost ◽  
Limited Capacity ◽  
Epidemic Dynamics ◽  
Optimal Intervention ◽  
Intervention Measures ◽  
Capacity Level ◽  
Parametric Specification ◽  
Short Transition

AbstractWe consider here an extended SIR model, including several features of the recent COVID-19 outbreak: in particular the infected and recovered individuals can either be detected (+) or undetected (−) and we also integrate an intensive care unit capacity. Our model enables a tractable quantitative analysis of the optimal policy for the control of the epidemic dynamics using both lockdown and detection intervention levers. With parametric specification based on literature on COVID-19, we investigate sensitivity of various quantities on optimal strategies, taking into account the subtle tradeoff between the sanitary and the economic cost of the pandemic, together with the limited capacity level of ICU. We identify the optimal lockdown policy as an intervention structured in 4 successive phases: First a quick and strong lockdown intervention to stop the exponential growth of the contagion; second a short transition phase to reduce the prevalence of the virus; third a long period with full ICU capacity and stable virus prevalence; finally a return to normal social interactions with disappearance of the virus. We also provide optimal intervention measures with increasing ICU capacity, as well as optimization over the effort on detection of infectious and immune individuals.

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