scholarly journals What can we learn from COVID-19 data by using epidemic models with unidentified infectious cases?

2021 ◽  
Author(s):  
quentin Griette ◽  
Jacques Demongeot ◽  
pierre magal
Keyword(s):  
Social Interactions ◽  
Reproduction Number ◽  
Transmission Rate ◽  
Social Effects ◽  
Time Dependent ◽  
Reproduction Numbers ◽  
The Social ◽  
The World ◽  
Early Beginning ◽  
Case Data

Background: The COVID-19 epidemic, which started in late December 2019 and rapidly spread throughout the world, was accompanied by an unprecedented release of reported case data. Our objective is to propose a fresh look at this data by coupling a phenomenological description to the epidemiological dynamics. Methods: We use a phenomenological model to describe and regularize the data. This model can be matched by a single mathematical model reproducing the epidemiological dynamics with a time-dependent transmission rate. We provide a method to compute this transmission rate and reconstruct the changes in the social interactions between people as well as changes in host-pathogen interactions. This method is applied to the cumulative case data of 8 different geographic areas. Findings: We reconstruct the transmission rate from the data, therefore we are in position to understand the contribution of the dynamical effects of social interactions (contacts between individuals) and the contribution of the dynamics of the epidemic. We deduce from the comparison of several instantaneous reproduction numbers that the social effects are the most important in the dynamic of COVID-19. We obtain an instantaneous reproduction number that stays below $3.5$ from early beginning of the epidemic. Conclusion: The instantaneous reproduction number staying below $3.5$ implies that it is sufficient to vaccinate $71\%$ of the population in each state or country considered in our study. Therefore assuming the vaccines will remain efficient against the new variants, and to be more confident it is sufficient to vaccinate $75-80\%$ to get rid of COVID-19 in each state or country. Funding: This research was funded by the Agence Nationale de la Recherche in France (Project name: MPCUII (PM) and (QG))

scholarly journals What can we learn from COVID-19 data by using epidemic models with unidentified infectious cases?

2021 ◽  
Vol 19 (1) ◽  
pp. 537-594
Author(s):  
Quentin Griette ◽  
◽  
Jacques Demongeot ◽  
Pierre Magal ◽  
Keyword(s):  
Social Interactions ◽  
Phenomenological Model ◽  
Epidemic Model ◽  
Reproduction Number ◽  
Transmission Rate ◽  
Time Dependent ◽  
Wave Dynamics ◽  
Dependent Rate ◽  
Reproduction Numbers ◽  
The One

<abstract><p>The COVID-19 outbreak, which started in late December 2019 and rapidly spread around the world, has been accompanied by an unprecedented release of data on reported cases. Our objective is to offer a fresh look at these data by coupling a phenomenological description to the epidemiological dynamics. We use a phenomenological model to describe and regularize the reported cases data. This phenomenological model is combined with an epidemic model having a time-dependent transmission rate. The time-dependent rate of transmission involves changes in social interactions between people as well as changes in host-pathogen interactions. Our method is applied to cumulative data of reported cases for eight different geographic areas. In the eight geographic areas considered, successive epidemic waves are matched with a phenomenological model and are connected to each other. We find a single epidemic model that coincides with the best fit to the data of the phenomenological model. By reconstructing the transmission rate from the data, we can understand the contributions of the changes in social interactions (contacts between individuals) on the one hand and the contributions of the epidemiological dynamics on the other hand. Our study provides a new method to compute the instantaneous reproduction number that turns out to stay below $ 3.5 $ from the early beginning of the epidemic. We deduce from the comparison of several instantaneous reproduction numbers that the social effects are the most important factor in understanding the epidemic wave dynamics for COVID-19. The instantaneous reproduction number stays below $ 3.5 $, which implies that it is sufficient to vaccinate $ 71\% $ of the population in each state or country considered in our study. Therefore, assuming the vaccines will remain efficient against the new variants and adjusting for higher confidence, it is sufficient to vaccinate $ 75-80\% $ to eliminate COVID-19 in each state or country.</p></abstract>

COVID-19: Time-Dependent Effective Reproduction Number and Sub-notification Effect Estimation Modeling (Preprint)

2020 ◽  
Author(s):  
Eduardo Atem De Carvalho ◽  
Rogerio Atem De Carvalho
Keyword(s):  
New York ◽  
Reproduction Number ◽  
Moving Average ◽  
Real Data ◽  
Time Dependent ◽  
Initial Value ◽  
Health Authorities ◽  
Reproduction Numbers ◽  
Effect Estimation ◽  
The Impact

BACKGROUND Since the beginning of the COVID-19 pandemic, researchers and health authorities have sought to identify the different parameters that govern their infection and death cycles, in order to be able to make better decisions. In particular, a series of reproduction number estimation models have been presented, with different practical results. OBJECTIVE This article aims to present an effective and efficient model for estimating the Reproduction Number and to discuss the impacts of sub-notification on these calculations. METHODS The concept of Moving Average Method with Initial value (MAMI) is used, as well as a model for Rt, the Reproduction Number, is derived from experimental data. The models are applied to real data and their performance is presented. RESULTS Analyses on Rt and sub-notification effects for Germany, Italy, Sweden, United Kingdom, South Korea, and the State of New York are presented to show the performance of the methods here introduced. CONCLUSIONS We show that, with relatively simple mathematical tools, it is possible to obtain reliable values for time-dependent, incubation period-independent Reproduction Numbers (Rt). We also demonstrate that the impact of sub-notification is relatively low, after the initial phase of the epidemic cycle has passed.

scholarly journals Fractional SIR-Model for Estimating Transmission Dynamics of COVID-19 in India

J ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 86-100
Author(s):  
Nita H. Shah ◽  
Ankush H. Suthar ◽  
Ekta N. Jayswal ◽  
Ankit Sikarwar
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Transmission Rate ◽  
Sir Model ◽  
Time Dependent ◽  
Contact Rate ◽  
Distribution Maps ◽  
Fundamental Parameters ◽  
Different Order ◽  
The Basic Reproduction Number

In this article, a time-dependent susceptible-infected-recovered (SIR) model is constructed to investigate the transmission rate of COVID-19 in various regions of India. The model included the fundamental parameters on which the transmission rate of the infection is dependent, like the population density, contact rate, recovery rate, and intensity of the infection in the respective region. Looking at the great diversity in different geographic locations in India, we determined to calculate the basic reproduction number for all Indian districts based on the COVID-19 data till 7 July 2020. By preparing district-wise spatial distribution maps with the help of ArcGIS 10.2, the model was employed to show the effect of complete lockdown on the transmission rate of the COVID-19 infection in Indian districts. Moreover, with the model's transformation to the fractional ordered dynamical system, we found that the nature of the proposed SIR model is different for the different order of the systems. The sensitivity analysis of the basic reproduction number is done graphically which forecasts the change in the transmission rate of COVID-19 infection with change in different parameters. In the numerical simulation section, oscillations and variations in the model compartments are shown for two different situations, with and without lockdown.

scholarly journals Estimation of the Time-dependent Reproduction Number of Influenza A(H1N1)pdm2009 in South Korea

2020 ◽  
Author(s):  
Yunjeong Lee ◽  
Dong Han Lee ◽  
Hee-Dae Kwon ◽  
Changsoo Kim ◽  
Jeehyun Lee
Keyword(s):  
South Korea ◽  
Influenza A ◽  
Reproduction Number ◽  
Time Estimation ◽  
Time Dependent ◽  
Estimation Of Parameters ◽  
Transmission Potential ◽  
Reproduction Numbers ◽  
Influenza A H1n1 ◽  
Feasible Range

Abstract Background: The reproduction number is one of the most crucial parameters in determining disease dynamics, providing a summary measure of the transmission potential. However, estimating this value is particularly challenging owing to the characteristics of epidemic data, including non-reproducibility and incompleteness.Methods: In this study, we propose mathematical models with different population structures; each of these models can produce data on the number of cases of the influenza A(H1N1)pdm09 epidemic in South Korea. These structured models incorporating the heterogeneity of age and region are used to estimate the time-dependent effective reproduction numbers. Subsequently, the age- and region-specific reproduction numbers are also computed to analyze the differences illustrated in the incidence data.Results: The basic SIR fails to provide a reasonable estimation of the reproduction numbers. The estimated values demonstrate a large variation and remains outside of the feasible range for the influenza, regardless of the time period for data. Real-time estimation using age- and region-structured models demonstrated that the effective reproduction number rose sharply during mid-October when the ㅜumber of patients increased dramatically. The reproduction number fell below unity at the end of October and stayed lower than unity indicating that the epidemic starts decreasing, which is consistent with the incidence data.Conclusions: Numerical results reveal that the introduction of heterogeneity into the population to represent the general characteristics of dynamics is essential for the robust estimation of parameters.

scholarly journals Indigenous Cosmopolitanisms of Music in Sámi Theatre

2021 ◽  
Vol 33 ◽  
pp. 119-146
Author(s):  
Klisala Harrison
Keyword(s):  
Social Interactions ◽  
Social Processes ◽  
Set Design ◽  
Musical Experience ◽  
Sound Effects ◽  
The Social ◽  
Theatre Companies ◽  
The World ◽  
Theatrical Performances ◽  
Musical Genres

Which kinds of Sáminess are expressed and engaged with music in Sámi theatre? Through descriptions of the kinds of musical genres and sounds presented, the article argue that the music of Sámi theatre can typically be described as cosmopolitan. As the musical expressions and engagements convey what is Sáminess, they present cosmopolitan versions of Sáminess. The author interprets performance moments as presenting types of Indigenous cosmopolitanism, in other words, Indigenous cosmopolitanisms. The article approaches music as musicking, which refers to all of the social interactions that go into creating a musical experience. Because this is theatre, this includes the social processes of staging other theatre values that relate with the music during theatrical performances. Other theatre values include costumes, set design, props, lighting, sound effects beyond music and movement such as dance and blocking. Overall, the productions perform a dynamic and fluid Sáminess that incorporates sounds, sights and movements from around the world, while often being “rooted” in what it is to be Sámi today and historically. Although most productions include identifiably Sámi music genres such as joik, it is worthwhile to note that some don’t. In these productions, the author identifies specific varieties of cosmopolitanism, such as vernacular cosmopolitanism, different forms of rooted cosmopolitanism and pan-Indigenous cosmopolitanism. The article examines case studies from Sámi theatre companies in Norway, Beaivváš Sámi Našunálateáhter and Åarjelhsaemien Teatere. The cases, among other productions, are the joik operas The Frost Haired and the Dream Seer and Allaq; the dance theatre productions Eatnemen Vuelieh and Gïeje; and the stage plays Silbajárviand Almmiriika.

scholarly journals Assessment of Vaccination and Underreporting on COVID-19 Infections in Turkey Based On Effective Reproduction Number

2021 ◽  
Author(s):  
Tuğba Akman Yıldız ◽  
Emek Köse ◽  
Necibe Tuncer
Keyword(s):  
Critical Parameter ◽  
Reproduction Number ◽  
Transmission Rate ◽  
Vaccination Rate ◽  
Future Trend ◽  
Time Dependent ◽  
Modified Model ◽  
Department Of Health ◽  
Number Of Patients ◽  
The Impact

AbstractIn this paper, we introduce a SEIR type COVID-19 model where the infected class is further divided into individuals in intensive care (ICUs) and ventilation units. The model is validated with the COVID-19 cases, deaths, and the number of patients in ICUs and ventilation units as reported by Turkey Department of Health for the period March 11 through May 30 when the nationwide lockdown is in order. COVID-19 interventions in Turkey are incorporated into the model to detect the future trend of the outbreak accurately. The lockdown is lifted on June 1, and the model is modified to include a time dependent transmission rate which is linked to the effective reproduction number ℛt through basic reproduction number ℛ0. The modified model captures the changing dynamics and peaks of the outbreak successfully. With the onset of vaccination on 13 January 2021, we augment the model with the vaccination class to investigate the impact of vaccination rate and efficacy. We observe that vaccination rate is a more critical parameter than the vaccine efficacy to eliminate the disease successfully.

scholarly journals COVID-19 Time-varying Reproduction Numbers Worldwide: An Empirical Analysis of Mandatory and Voluntary Social Distancing

2021 ◽  
Author(s):  
Alexander Chudik ◽  
M. Hashem Pesaran ◽  
Alessandro Rebucci
Keyword(s):  
Reproduction Number ◽  
Transmission Rate ◽  
Economic Incentives ◽  
Moment Condition ◽  
Time Varying ◽  
Linear Interaction ◽  
Susceptible Population ◽  
Social Distancing ◽  
Transmission Rates ◽  
Reproduction Numbers

AbstractThis paper estimates time-varying COVID-19 reproduction numbers worldwide solely based on the number of reported infected cases, allowing for under-reporting. Estimation is based on a moment condition that can be derived from an agent-based stochastic network model of COVID-19 transmission. The outcomes in terms of the reproduction number and the trajectory of per-capita cases through the end of 2020 are very diverse. The reproduction number depends on the transmission rate and the proportion of susceptible population, or the herd immunity effect. Changes in the transmission rate depend on changes in the behavior of the virus, re-flecting mutations and vaccinations, and changes in people’s behavior, reflecting voluntary or government mandated isolation. Over our sample period, neither mutation nor vaccination are major factors, so one can attribute variation in the transmission rate to variations in behavior. Evidence based on panel data models explaining transmission rates for nine European countries indicates that the diversity of outcomes resulted from the non-linear interaction of mandatory containment measures, voluntary precautionary isolation, and the economic incentives that gov-ernments provided to support isolation. These effects are precisely estimated and robust to various assumptions. As a result, countries with seemingly different social distancing policies achieved quite similar outcomes in terms of the reproduction number. These results imply that ignoring the voluntary component of social distancing could introduce an upward bias in the estimates of the effects of lock-downs and support policies on the transmission rates.JEL ClassificationD0, F6, C4, I120, E7

Précis of How the brain got language: The Mirror System Hypothesis

2013 ◽  
Vol 5 (2-3) ◽  
pp. 107-131 ◽  
Author(s):  
Michael A. Arbib
Keyword(s):  
Social Interactions ◽  
Cultural Evolution ◽  
Language Change ◽  
Homo Sapiens ◽  
Biological Evolution ◽  
Social Structures ◽  
Short Answer ◽  
The Social ◽  
The World ◽  
The Brain

The short answer to the question of How the Brain Got Language is “through biological and cultural evolution.” The challenge is to be more specific. I use the term “the language-ready brain” to suggest that the brain of early Homo sapiens was adequate to support language but that it required tens of millennia for humans to be able to exploit these innate neural capabilities to develop, cumulatively, languages and the societies that made languages possible and necessary. The ability to surf the World Wide Web is a recent example of society's expanding ability to develop technologies and social structures which allow humans to exploit their neural capabilities in ways that were not part of the adaptive pressures for biological evolution.The two-fold challenge of the book, then, is to understand (i) what are the mechanisms of the language-ready brain and what adaptive pressures evolved them biologically; and (ii) how did those mechanisms support the emergence of language as well as modern-day patterns of language change, acquisition and use, and the social interactions which support them?

scholarly journals Stepping out of lockdown should start with school re-openings while maintaining distancing measures. Insights from mixing matrices and mathematical models.

2020 ◽  
Author(s):  
Emma Sue McBryde ◽  
James M Trauer ◽  
Adeshina Adekunle ◽  
Romain Ragonnet ◽  
Michael T Meehan
Keyword(s):  
Spectral Radius ◽  
Reproduction Number ◽  
Positive Outcome ◽  
Attendance Rates ◽  
Considerable Uncertainty ◽  
Effective Contact ◽  
Reproduction Numbers ◽  
The World ◽  
The Impact ◽  
Sensitivity And Uncertainty Analysis

Australia is one of a few countries which has managed to control COVID-19 epidemic before a major epidemic took place. Currently with just under 7000 cases and 100 deaths, Australia is seeing less than 20 new cases per day. This is a positive outcome, but makes estimation of current effective reproduction numbers difficult to estimate. Australia, like much of the world is poised to step out of lockdown and looking at which measures to relax first. We use age-based contact matrices, calibrated to Chinese data on reproduction numbers and difference in infectiousness and susceptibility of children to generate next generation matrices (NGMs) for Australia. These matrices have a spectral radius of 2.49, which is hence our estimated basic reproduction number for Australia. The effective reproduction number (Reff) for Australia during the April/May lockdown period is estimated by other means to be around 0.8. We simulate the impact of lockdown on the NGM by first applying observations through Google Mobility Report for Australia at 3 locations: home (increased contacts by 18%), work (reduced contacts by 34%) and other (reduced contacts by 40%), and we reduce schools to 3% reflecting attendance rates during lockdown. Applying macro-distancing to the NGM leads to a spectral radius of 1.76. We estimate that the further reduction of the reproduction number to current levels of Reff = 0.8 is achieved by a micro-distancing factor of 0.26. That is, in a given location, people are 26% as likely as usual to have an effective contact with another person. We apply both macro and micro-distancing to the NGMs to examine the impact of different exit strategies. We find that reopening schools is estimated to reduce Reff from 0.8 to 0.78. This is because increase in school contact is offset by decrease in home contact. The NGMs all estimate that adults aged 30-50 are responsible for the majority of transmission. We also find that micro-distancing is critically important to maintain Reff <1. There is considerable uncertainty in these estimates and a sensitivity and uncertainty analysis is presented.

scholarly journals Simple Forward Finite Difference for Computing Reproduction Number of COVID-19 in Indonesia During the New Normal

2021 ◽  
Vol 5 (1) ◽  
pp. 88
Author(s):  
Suryasatriya Trihandaru ◽  
Hanna Arini Parhusip ◽  
Bambang Susanto ◽  
Yohanes Sardjono
Keyword(s):  
Finite Difference ◽  
Reproduction Number ◽  
Research Result ◽  
Sir Model ◽  
Rate Of Change ◽  
Time Dependent ◽  
Normal System ◽  
New Normal ◽  
Reproduction Numbers ◽  
Normal Period

The research purpose shown in this article is describing the time dependent reproduction number of coronavirus called by COVID-19 in the new normal period  for 3 types areas, i.e. small, medium and global areas by considering the number of people in these areas.  It is known that in early June 2020, Indonesia has claimed to open activities during the pandemic with the new normal system. Though the number of COVID-19 cases is still increasing in almost infected areas, normal activities are coming back with healty care protocols where public areas are opened as usual with certain restrictions. In order to have observations of spreading impact of COVID-19, the basic reproduction number (Ro)  i.e. the reproduction number (Ro) is the ratio between 2 parameters of SIR model where SIR stands for Susceptible individuals, Infected individuals, and Recovered individuals respectively. The reproduction numbers  are computed as discrete values depending on time. The used research method is  finite difference scheme for computing rate of change parameters in SIR models based on the COVID-19 cases in Indonesia (global area), Jakarta (medium area) and Salatiga (small area) by considering the number of people in these areas respectively. The simple forward finite difference is employed to the SIR model to have time dependent of parameters. The second approach is using the governing linear system to obtain the values of parameter daily. These parameters are computed for each day such that the values of Ro are obtained as function of time. The research result shows that 3 types areas give the same profiles of parameters that the rate of changes of reproduction numbers are decreasing with respect to time. This concludes that the reproduction numbers are most likely decreasing.

Sign in / Sign up

Export Citation Format

Share Document