scholarly journals Modeling the COVID-19 transmission in Italy: The roles of asymptomatic cases, social distancing, and lockdowns in the first and the second waves

2021 ◽  
Author(s):  
Muhamad Khairul Bahri
Keyword(s):  
Behavioral Measures ◽  
Seir Model ◽  
Social Distancing ◽  
The World ◽  
Second Wave ◽  
Very High

AbstractThe SEIR model of COVID-19 is developed to investigate the roles of physical distancing, lockdowns and asymptomatic cases in Italy. In doing so, two types of policies including behavioral measures and lockdown measures are embedded in the model. Compared with existing models, the model successfully reproduces similar multiple observed outputs such as infected and recovered patients in Italy by July 2020. This study concludes that the first policy is important once the number of infected cases is relatively low. However, once the number of infected cases is very high so the society cannot identify infected and disinfected people, the second policy must be applied soon. It is thus this study suggests that relaxed lockdowns lead to the second wave of the COVID-19 around the world. It is hoped that the model can enhance our understanding on the roles of behavioral measures, lockdowns, and undocumented cases, so-called asymptomatic cases, on the COVID-19 flow.

scholarly journals Modeling the Effect of Asymptomatic Cases, Social Distancing, and Lockdowns in the First and Second waves of the COVID-19 Pandemic: A Case Study of Italy

2021 ◽  
Vol 3 (3) ◽  
pp. 265-273
Author(s):  
Muhamad Khairulbahri
Keyword(s):  
Full Text ◽  
Behavioral Measures ◽  
Seir Model ◽  
Social Distancing ◽  
The World ◽  
Second Wave

The SEIR model of COVID-19 is developed to investigate the roles of physical distancing, lockdowns, and asymptomatic cases in Italy. In doing so, two types of policies including behavioral measures and lockdown measures are embedded in the model. Compared with existing models, the model successfully reproduces similar multiple observed outputs such as infected and recovered patients in Italy by July 2020. This study concludes that the first policy is important once the number of infected cases is relatively low. However, once the number of infected cases is too high, so the society cannot identify infected and disinfected people, the second policy must be applied soon. It is thus this study suggests that relaxed lockdowns lead to the second wave of the COVID-19 around the world. It is hoped that the model can enhance our understanding of the roles of behavioral measures, lockdowns, and undocumented cases, so-called asymptomatic cases, on the COVID-19 flow. Doi: 10.28991/SciMedJ-2021-0303-8 Full Text: PDF

scholarly journals Bayesian small-area modelling of COVID-19 cases and deaths in England and association with key risk factors: a combined space–time Susceptible-Exposed-Infected-Removed (SEIR) model

2020 ◽  
Author(s):  
Benn Sartorius ◽  
Andrew Lawson ◽  
Rachel L. Pullan
Keyword(s):  
Risk Factors ◽  
Small Area ◽  
Mortality Rates ◽  
Space Time ◽  
Spatiotemporal Variability ◽  
Population Mobility ◽  
Seir Model ◽  
Social Distancing ◽  
The Impact ◽  
Second Wave

Abstract Background: COVID-19 caseloads in England appear have passed through a first peak, with evidence of an emerging second wave. To ensure continued response to the epidemic is most effective, it is imperative to better understand both retrospectively and prospectively the geographical evolution of COVID-19 caseloads and deaths, identify localised areas in space-time at significantly higher risk, quantify the impact of changes in localised population mobility (or movement) on caseloads, identify localised risk factors for increased mortality and project the likely course of the epidemic at small-area resolution in coming weeks.Methods: We applied a Bayesian space–time SEIR model to assess the spatiotemporal variability of COVID-19 caseloads (transmission) and deaths at small-area scale in England (Middle Layer Super Output Area [MSOA], 6791 units) and by week (using observed data from week 5 to 34), including key determinants, the modelled transmission dynamics and spatial-temporal random effects. We also estimate the number of cases and deaths at small-area resolution with uncertainty projected forward in time by MSOA (up to week 51 of 2020), the impact mobility reductions (and subsequent easing) have had on COVID-19 caseloads and quantify the impact of key socio-demographic risk factors on COVID-19 related mortality risk by MSOA.Results: Reductions in population mobility due the course of the first lockdown had a significant impact on the reduction of COVID-19 caseloads across England, however local authorities have had a varied rate of reduction in population movement which our model suggest has substantially impacted the geographic heterogeneity in caseloads at small-area scale. The steady gain in population mobility, observed from late April, appears to have contributed to a slowdown in caseload reductions towards late June and subsequent steady increase signalling the start of the second wave. MSOA with higher proportions of elderly (70+ years of age) and elderly living in deprivation, both with very distinct geographic distributions, have a significantly elevated COVID-19 mortality rates.Conclusions: While non-pharmaceutical interventions (that is, reductions in population mobility and social distancing) had a profound impact on the trajectory of the first wave of the COVID-19 outbreak in England, increased population mobility appears to have contributed to the current increase signalling the start of the second wave. A number of contiguous small-areas appear to be at a significant elevated risk of high COVID-19 transmission, many of which are also at increased risk for higher mortality rates. A geographically staggered re-introduction of intensified social distancing measures is advised and limited cross MSOA movement if the magnitude and geographic extent of the second wave is to be reduced.

scholarly journals Understanding the First and the Second Waves of the COVID-19 in Germany: Is our Social Behavior Enough to Protect us from the Pandemic?

2021 ◽  
Vol 18 (15) ◽  
Author(s):  
Muhamad KHAIRULBAHRI
Keyword(s):  
Young People ◽  
Computer Model ◽  
Health Workers ◽  
Public Spaces ◽  
Unknown Parameters ◽  
Behavioral Measures ◽  
Seir Model ◽  
Resource Needs ◽  
Second Wave ◽  
Death Cases

Like other European countries, Germany has experienced the 2nd wave of the COVID-19 amid obligations of social distancing and wearing of face masks in public spaces. Although Germany successfully contained the virus during the 1st wave, it has faced difficulties in controlling the COVID-19 during the 2nd wave. This study develops a computer model representing the COVID-19 flow in Germany by comparing the effects of the measures taken during the 1st and the 2nd waves. The computer model is based on the SEIR concept and the system dynamics (SD) approach in which some unknown parameters are estimated through the calibration process. Moreover, the SEIR computer model is developed by considering different cases in older and young people and the SEIR model successfully reproduces similar patterns of infected, recovered, and death cases in the 1st and the 2nd waves in Germany. The SEIR model also shows that the measures taken in the 1st wave have different efficacies than those in the 2nd wave, leading to higher infected cases during the 2nd wave. Since the SEIR model can successfully reproduce similar patterns, the SEIR model can be a basis for further studies in estimating other resource needs such as health workers, and bed capacities. HIGHLIGHTS The SEIR model estimates the efficacies of behavioral measures and lockdowns Behavioral measures are less effective than lockdowns Germany experienced higher infected cases in the first wave than in the second wave Relaxed lockdowns lead to higher infected cases in the second wave Lockdowns are the key to curb COVID-19 flow GRAPHICAL ABSTRACT

scholarly journals Epidemic Model Analysis of Covid-19

2021 ◽  
Vol 328 ◽  
pp. 06002
Author(s):  
Dayat Hidayat ◽  
Edwin Setiawan Nugraha
Keyword(s):  
Epidemic Model ◽  
Asymptotically Stable ◽  
Globally Asymptotically Stable ◽  
Seir Model ◽  
Infected People ◽  
Rate Of Spread ◽  
The World ◽  
Disease Free ◽  
Very High ◽  
Two Equilibria

Covid-19 is a very extraordinary case not only in one country but all countries in the world. The number of deaths caused by Covid-19 is very large and the rate of spread of this disease is very high and fast. In this paper, we perform an analysis of a covid-19 epidemic model. This model is a development of the SEIR model in general which is equipped with a Quarantine (Q), Fatality (F) compartment, and there is a separation between detected and undetected infected people (I). Our analysis shows that there are two equilibria, namely, disease free equilibrium and endemic equilibrium. by using, Lyapunov function, we demonstrated that disease free is globally asymptotically stable if R0 < 1, and disease-free becomes unstable if R0 > 1. This result reveal that the intervention of infection rate and quarantine process are important to control and achieve global stability of disease-free equilibrium

scholarly journals Modelling the second wave of COVID-19 infections in France and Italy via a Stochastic SEIR model

2021 ◽  
Author(s):  
Davide Faranda ◽  
Tommaso Alberti
Keyword(s):  
Initial Conditions ◽  
Asymptotic Estimates ◽  
Seir Model ◽  
Actual Knowledge ◽  
The World ◽  
Log Normal ◽  
Long Term Behavior ◽  
Second Wave ◽  
Log Normal Distribution

&lt;p&gt;COVID-19 has forced quarantine measures in several countries across the world. These measures have proven to be effective in significantly reducing the prevalence of the virus. To date, no effective treatment or vaccine is available. In the effort of preserving both public health as well as the economical and social textures, France and Italy governments have partially released lockdown measures. Here we extrapolate the long-term behavior of the epidemics in both countries using a Susceptible-Exposed-Infected-Recovered (SEIR) model where parameters are stochastically perturbed with a log-normal distribution to handle the uncertainty in the estimates of COVID-19 prevalence and to simulate the presence of super-spreaders. Our results suggest that uncertainties in both parameters and initial conditions rapidly propagate in the model and can result in different outcomes of the epidemics leading or not to a second wave of infections. Furthermore, the presence of super-spreaders adds instability to the dynamics, making the control of the epidemics more difficult. Using actual knowledge, asymptotic estimates of COVID-19 prevalence can fluctuate of order of ten millions units in both countries.&lt;/p&gt;

scholarly journals A modified SEIR Model with Confinement and Lockdown of COVID-19 for Costa Rica

2020 ◽  
Author(s):  
Tomas de-Camino-Beck
Keyword(s):  
Costa Rica ◽  
Fast Moving ◽  
Modern Society ◽  
Emerging Diseases ◽  
Time Varying ◽  
Seir Model ◽  
Contagious Disease ◽  
The World ◽  
Second Wave ◽  
Pharmaceutical Interventions

The fast moving post-modern society allows for individuals to move fast in and between different countries, making it a perfect situation for the spread of emerging diseases. COVID-19 emerged with properties of a highly contagious disease, that has spread rapidly around the world. SIR/SEIR models are generally used to explain the dynamics of epidemics, however Coronavirus has shown dynamics with constant non-pharmaceutical interventions, making it difficult to model with these simple models. We extend an SEIR model to include a confinement compartment (SEICR) and use this to explain data from COVID-19 epidemic in Costa Rica. Then we discuss possible second wave of infection by adding a time varying function in the model to simulate cyclic interventions.

Two Years after the Crisis: Do Risks of the Second Wave Become Stronger?

2011 ◽  
pp. 4-20
Author(s):  
M. Ershov
Keyword(s):  
High Risk ◽  
World Economy ◽  
External Shocks ◽  
Global Imbalances ◽  
Russian Economy ◽  
The World ◽  
The Future ◽  
Second Wave

With signs of normalization seemingly in place in the world economy, a number of problems show the possibility of aggravation in the future. The volume of derivatives in American banks grows significantly, high risk instruments are back in place and their use becomes more active, global imbalances increase. All of the above requires thorough approaches when creating mechanisms which can neutralize external shocks for the Russian economy and make it possible to develop in the new post-crisis environment.

IMPACT OF NATIONAL DISASTER COVID-19, INDONESIA TOWARDS ECONOMIC RECESSION

2020 ◽  
Author(s):  
endang naryono
Keyword(s):  
Developing Countries ◽  
Economic Recession ◽  
Developed Countries ◽  
Social Distancing ◽  
Poor Countries ◽  
Corona Virus ◽  
The World ◽  
History Of ◽  
National Disaster

Covid-19 or the corona virus is a virus that has become a disaster and a global humanitarian disaster began in December 2019 in Wuhan province in China, April 2020 the spread of the corona virus has spread throughout the world making the greatest humanitarian disaster in the history of human civilization after the war world II, Already tens of thousands of people have died, millions of people have been infected with the conona virus from poor countries, developing countries to developed countries overwhelmed by this virus outbreak. Increasingly, the spread follows a series of measurements while patients who recover recover from a series of counts so that this epidemic becomes a very frightening disaster plus there is no drug or vaccine for this corona virus yet found, so that all countries implement strategies to reduce this spread from social distancing, phycal distancing to with a city or country lockdown.

The chronicle of COVID-19: possible strategies to curb the pandemic

2020 ◽  
Vol 27 ◽  
Author(s):  
Rajesh Kumar ◽  
Seetha Harilal ◽  
Abdullah G. Al-Sehemi ◽  
Githa Elizabeth Mathew ◽  
Simone Carradori ◽  
...  
Keyword(s):  
Life Cycle ◽  
Research And Development ◽  
Vaccine Development ◽  
Therapeutic Strategies ◽  
Antiviral Drugs ◽  
Limited Data ◽  
Social Distancing ◽  
The World ◽  
Novel Virus ◽  
Day By Day

: COVID-19, an epidemic that emerged in Wuhan, has become a pandemic affecting worldwide and is in a rapidly evolving condition. Day by day, the confirmed cases and deaths are increasing many folds. SARS-CoV-2 is a novel virus; therefore, limited data are available to curb the disease. Epidemiological approaches, isolation, quarantine, social distancing, lockdown, and curfew are being employed to halt the spread of the disease. Individual and joint efforts all over the world are producing a wealth of data and information which are expected to produce therapeutic strategies against COVID-19. Current research focuses on the utilization of antiviral drugs, repurposing strategies, vaccine development as well as basic to advanced research about the organism and the infection. The review focuses on the life cycle, targets, and possible therapeutic strategies, which can lead to further research and development of COVID-19 therapy.

How India Fights with COVID-19 with Learning from Highly Affected Countries

2020 ◽  
Vol 15 ◽  
Author(s):  
Pooja Sharma ◽  
Karan Veer
Keyword(s):  
Risk Assessment ◽  
Gene Sequencing ◽  
Lessons Learned ◽  
World Health ◽  
Global Risk ◽  
The World ◽  
Global Risk Assessment ◽  
Health Organization ◽  
Very High ◽  
Breathing Problem

: It was 11 March 2020 when the World Health Organization (WHO) declared the name COVID-19 for coronavirus disease and also described it as a pandemic. Till that day 118,000 cases were confirmed of pneumonia with breathing problem throughout the world. At the start of New Year when COVID-19 came into knowledge a few days later, the gene sequencing of the virus was revealed. Today the number of confirmed cases is scary, i.e. 9,472,473 in the whole world and 484,236 deaths have been recorded by WHO till 26 June 2020. WHO's global risk assessment is very high [1]. The report is enlightening the lessons learned by India from the highly affected countries.

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