Journée COVID (31 Mai 2021)

La journée scientifique de la structure fédérative mathSTIC (LAGA-LIPN-L2TI) aura lieu 31 mai 2021.

La journée aura lieu à distance à cet adresse BBB .

Cette journée sera l'occasion pour reprendre l'activité scientifique de la Federation.

  8h45 Accueil
  9h20 -  9h30 Presentation de la federation et ses activitées (Roberto Wolfler Calvo)
 9h30 - 10h30

Principes et limites de la modélisation de l'épidémie de COVID-19 à différentes échelles et au cours de ses différentes vagues (Laurent Dumas)

 10h30 - 11h30

A stochastic SIR model with contact-tracing (Chi Tran)

 11h30 - 12h30

SafeCityMap project: What habits in people's mobility can reveal from a metropolitan area, before and during lockdown restrictions? (Aline Carneiro Viana)

 14h00 - 15h00 CTVI-COVID : image de la ventilation à partir de scanners tomodensitométriques pour la caractérisation précoce des patients COVID19 (David Sarrut)

 15h00 - 16h00

Modelling the impact of Covid-19 on older-age mortality (Andrew Cairns)

   

Résumés des exposés:

Laurent Dumas (Université de Versailles) : Principes et limites de la modélisation de l'épidémie de COVID-19 à différentes échelles et au cours de ses différentes vagues

On présente ici les principes généraux de la modélisation mathématique en épidémiologie et son application au cas particulier de l'épidémie de COVID-19 à différentes échelles (pays, région ou service hospitalier) et à différentes périodes depuis mars 2020. On montrera également  comment les  mesures sanitaires (confinement, port du masque), l'évolution de la maladie (variants) et de son traitement (vaccin) peuvent être prises en compte dans la modélisation.

 

Chi Tran (Université Gustave Eiffel) : A stochastic SIR model with contact-tracing

In this talk, we present a stochastic SIR model accounting for contact-tracing as well as a statistical method to estimate the parameters when the infective population is not observed. Approximate Bayesian Computation is used to overcome this problem. Applications for the AIDS epidemics and the Covid-19 epidemics are carried.

 

Aline Carneiro Viana (DR INRIA) : SafeCityMap project: What habits in people's mobility can reveal from a metropolitan area, before and during lockdown restrictions?

The COVID-19 pandemic highly perturbed our mobility patterns and use of urban spaces. This raises two important questions, addressed in the SafeCityMap project. First of all, we investigate how mobility patterns at an urban scale were affected by the pandemic, and especially by harsh lockdown conditions in Spring 2020. As such, 1st-phase SafeCityMap works toward the tracking of the evolution in space and time of population habits in mobility. Second, we believe that the modelling of such patterns as well as the analysis of how they were impacted by the 1st lockdown can provide useful intuitions on the epidemic spread, such as for COVID-19, on different areas of a city. This latter is related to the observation that high population concentration at certain hours and geographical area intuitively increases the probability of agglomeration and, consequently, the contamination and propagation risks. This is particularly probable in small and highly dense geographical zones. Still, this claim needs to be investigated from the epidemiological point of view and constitutes not-validated intuitions, which is left for the 2nd-phase of SafeCityMap. I will thus present the SafeCityMap's data-driven mobility analytics performed on two large-scale datasets collected in Ile de France region, and more particularly, in Paris departments, before and during the first lockdown. Such analysis corresponds to the results of the first phase of SafeCityMap. 

 

David Sarrut (DR1 CNRS) : CTVI-COVID : image de la ventilation à partir de scanners tomodensitométriques pour la caractérisation précoce des patients COVID19

Nous cherchons à évaluer l'intérêt des images de ventilation, dite CTVI (Computed Tomography Ventilation Image), quantifiant la répartition spatiale de la ventilation dans le poumon. Les CTVI sont calculées à partir de deux images tomodensitométriques (CT) acquises en blocage respiratoire en fin d'expiration et fin d'inspiration. Dans ces images, une estimation quantitative de la capacité de ventilation est disponible par voxel, permettant d'effectuer des analyses régionales. Cette répartition spatiale de la ventilation dans le poumon pourrait servir de biomarqueur (sévérité, pronostic, etc). De manière plus générale, les méthodes développées ne sont pas uniquement spécifiques au COVID et peuvent être utiles également pour d'autres SDRA et COPD. Nous présenterons également la base de données COVID-CTPRED (CHU Saint Etienne) et les différentes activités associées (https://covid.creatis.insa-lyon.fr)

 

Andrew Cairns (Heriot-Watt University) : Modelling the impact of Covid-19 on older-age mortality

This presentation will look at Covid-19 mortality experience (mainly in the 50+ age group) and what impact this has had over the last two years and might have on future mortality. We will first look at how Covid-19 mortality experience compares with all-cause mortality using English data, once we have allowed for varying infection rates across the population. A key conclusion is that there is a strong proportionality relationship between Covid-19 death rates and all-cause mortality by age and by socio-economic group (e.g. by deprivation). What we then observe as higher death rates in specific groups can then mainly be attributable to variations in infection rates (e.g. regional or socio-economic variation). Second, we will look at the future mortality prospects for those who survive the pandemic. A simple model will be presented that allows us to explore this question. In the absence of secondary effects of the pandemic, survivors are likely to be healthier than the pre-pandemic population, with a corresponding small increase in life expectancies. However, further adjustments will need to be made when we begin to quantify the secondary impacts of Covid including long-term impairments ("long Covid") and the impact of delayed treatments for other illnesses such as cancers.

 

Short bio des intervenants

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Laurent Dumas est Professeur en Mathématiques Appliquées au Laboratoire de Mathématiques de l'Université de Versailles (UVSQ). Directeur de l'UFR des Sciences depuis Nov. 2020. Depuis 2015: co-directeur (et fondateur) de l'Institut IMOSE (rattaché à l'UVSQ). ses intérêts de recherche sont : l’optimisation et applications médicales ou industrielles; la modélisation et simulation de phénomènes complexes; la théorie cinétique. Il a été directeur du département de mathématiques de l'UVSQ de 2012 à 2016 et responsable du Master Paris Saclay Analyse, Modélisation et Simulation (2012-2020)

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C. Tran est Professeur à l'Université Gustave-Eiffel (Marne-la Vallée). Spécialiste de mathématiques appliquées à la biologie et à la médecine (plusieurs articles avec Yazdanpanah, directeur de l'ANRS). Il est un des plus proches collaborateurs de notre collègue Jean-Stéphane Dhersin, avec qui il a plusieurs publications et une codirection de thèse (Thi Phuong Thuy Vo).

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Aline Carneiro Viana is a Senior Reseach Director (DR) at Inria, where she leads the TRiBE team. After a 1-year sabbatical leave at the TKN Group of the TU-Berlin, Germany, she got her habilitation degree from UPMC - Sorbonne Universités, France in 2011. Dr. Viana got her PhD in Computer Science from the UPMC - Sorbonne Universit\'{e}s in 2005. Her research addresses the design of solutions for tactful networking, smart cities, mobile and self-organizing networks with the focus on human behavior analysis. She is a recipient of the French Scientific Excellence award since 2015 and for 6 years now and was nominated in 2016 as one of the "10 women in networking/communications that you should Watch" (1st-year nomination of N2Women community).

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D. Sarrut (DR1 CNRS) works in the fields of medical image processing, simulations and medical physics. The principal applications are related to the treatment of cancer by radiotherapy and imaging with ionizing radiation (x-ray tomography, nuclear imaging). He co-authored more than 80 international journal articles, more than 70 papers in international conferences and participated in 10 European and ANR projects. He supervised 15 defended PhD theses (3 on-going). He obtained the HDR ("Habilitation à Diriger des Recherche") in 2008. He is the leader of the team "Tomoradio" at CREATIS laboratory ("Tomographic imaging and therapy with radiation") partly located in the Léon Bérard cancer center in Lyon.

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A. Cairns est Professeur à Heriot-Watt University, Édimbourg. Spécialiste de la recherche en actuariat. Membre de la Royal Society of Edinburg (l'équivalent de l'académie des sciences en Écosse). Prix et distinctions : Halmstad Prize (2008), Society of Actuaries Annual Prize (2009), Robert I. Mehr Award (2016).