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  • Open Access
    Authors: 
    Emma Hubert; Thibaut Mastrolia; Dylan Possamaï; Xavier Warin;
    Publisher: Springer Science and Business Media LLC
    Countries: United States, France
    Project: ANR | PACMAN (ANR-16-CE05-0027)

    In this work, we provide a general mathematical formalism to study the optimal control of an epidemic, such as the COVID-19 pandemic, via incentives to lockdown and testing. In particular, we model the interplay between the government and the population as a principal-agent problem with moral hazard, à la Cvitanić et al. (Finance Stoch 22(1):1-37, 2018), while an epidemic is spreading according to dynamics given by compartmental stochastic SIS or SIR models, as proposed respectively by Gray et al. (SIAM J Appl Math 71(3):876-902, 2011) and Tornatore et al. (Phys A Stat Mech Appl 354(15):111-126, 2005). More precisely, to limit the spread of a virus, the population can decrease the transmission rate of the disease by reducing interactions between individuals. However, this effort-which cannot be perfectly monitored by the government-comes at social and monetary cost for the population. To mitigate this cost, and thus encourage the lockdown of the population, the government can put in place an incentive policy, in the form of a tax or subsidy. In addition, the government may also implement a testing policy in order to know more precisely the spread of the epidemic within the country, and to isolate infected individuals. In terms of technical results, we demonstrate the optimal form of the tax, indexed on the proportion of infected individuals, as well as the optimal effort of the population, namely the transmission rate chosen in response to this tax. The government's optimisation problems then boils down to solving an Hamilton-Jacobi-Bellman equation. Numerical results confirm that if a tax policy is implemented, the population is encouraged to significantly reduce its interactions. If the government also adjusts its testing policy, less effort is required on the population side, individuals can interact almost as usual, and the epidemic is largely contained by the targeted isolation of positively-tested individuals.

  • Open Access English
    Authors: 
    Schultz, Émilien; Atlani-Duault, L; Peretti-Watel, p; Ward, J,;
    Publisher: HAL CCSD
    Country: France

    Objectives In the early stages of the coronavirus disease 2019 (COVID-19) pandemic, chloroquine and its derivatives such as hydroxychloroquine (HCQ) were widely commented upon both within the scientific community and in the media. This paper explores the different factors that influenced public perceptions in France of the efficacy of HCQ as well as their evolution between April 2020 and June 2021. Methods This article draws on 5 surveys conducted among representative samples of the French population (projects COCONEL and TRACTRUST; quota method, n = 1006; 1004; 2006; 1014 and 1005). We asked questions on the effectiveness of chloroquine against COVID-19. We also collected sociodemographic variables and attitudes toward politics and science. Results Between April and June 2021, the proportion of respondents who believed in the efficacy of HCQ decreased rapidly from 35% to 14%. The proportion of respondents who believed that HCQ is ineffective rose gradually from 6% to 21%. After adjusting for the temporal effect, the logistic regression showed a very strong association between political orientation and the belief in the efficacy of HCQ. Respondents who felt closest to the more radical parties (far-right and far-left) were more likely to believe in the efficacy of HCQ than those who felt closest to the political center (O.R. 2.48 [1.95–3.15] and 1.87 [1.44–2.43]). The role of trust in the government and in science and of the degree of political engagement were investigated in the two waves conducted after the scientific consensus was established during the summer of 2020. High levels of trust in the government and in science and of politicization are associated with belief of HCQ proven inefficacy. Across the whole period, a majority of respondents were uncertain. Even in 2021, 41.5% stated that the data were insufficient to decide whether or not HCQ is effective and 25.2% stating that they did not know. Conclusion Because media coverage of scientific controversies is higher in times of uncertainty than after these controversies have died down, the publicization of therapeutic promises can have lasting consequences on attitudes towards science and medicine.

  • Open Access English
    Authors: 
    Mariana Galvão Ferrarini; Aguiar-Pulido; Eric T. Dawson; Andrea Guarracino; Andreas Gruber; Lukas Heumos; Alexander Kanitz; Amit Kumar Lal; Brett E. Pickett; Rita Rebollo; +15 more
    Publisher: HAL CCSD
    Country: France

    As part of the virtual BioHackathon 2020, we formed a working group that focused on the analysis of gene expression in the context of COVID-19. More specifically, we performed transcriptome analyses on published datasets in order to better understand the interaction between the human host and the SARS-CoV-2 virus.The ideas proposed during this hackathon were divided into five projects. Projects 1 and 2 aimed to identify human genes that are important in the process of viral infection of human cells. Projects 3 and 4 aimed to take the candidate genes identified in projects 1 and 2, as well as by independent studies, and relate them to clinical information and to possible therapeutic interventions. Finally, Project 5 aimed to package and containerize software and workflows used and generated here in a reusable manner, ultimately providing scalable and reproducible workflows.

  • English
    Authors: 
    Radtchenko-Draillard, Svetlana;
    Publisher: HAL CCSD
    Country: France

    After having carried out the analysis of numerous intercultural comparative studies and my theoretical-empirical studies on the state of mental health in the academic spheres of different countries, the purpose of my article is to describe the major causes and consequences of the mental health of students, teachers and researchers in recent years and in particular during the Covid 19 epidemic, then synthesize the main reflections on the effectiveness of medicalpsychological centers for their optimization.; Après avoir réalisé l’analyse de nombreuses études comparatives interculturelles et mes études théoriques-empiriques sur l’état de santé mentale dans les sphères académiques de différents pays, le but de mon article est de décrire les causes et conséquences majeures de la santé mentale des étudiants, enseignants et chercheurs ces dernières années et en particulier pendant l’épidémie de Covid 19, puis synthétiser les principales réflexions sur l’efficacité des centres médico-psychologiques pour leur optimisation. Mots-clés : santé mentale, dépression, anxiété, stress, burn-out, épidémie de coronavirus (Covid 19), soins médico-psychologiques.

  • Open Access
    Authors: 
    Katarzyna Polak; Noémie Greze; Maëlle Lachat; Delphine Merle; Steve Chiumento; Christelle Bertrand-Gaday; Bernadette Nadine Trentin; Robert Z. Mamoun;
    Publisher: Cold Spring Harbor Laboratory
    Country: France

    AbstractExtracellular vesicles (EVs) emerge as essential mediators of intercellular communication. DNA vaccines encoding antigens presented on EVs efficiently induce T-cell responses and EV-based vaccines containing the Spike (S) proteins of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) are highly immunogenic in mice. Thus, EVs may serve as vaccine platforms against emerging diseases, going beyond traditional strategies, with the antigen displayed identically to the original protein embedded in the viral membrane and presented as such to the immune system. Compared to their viral and pseudotyped counterparts, EV-based vaccines overcome many safety issues including pre-existing immunity against these vectors. Here, we applied our technology in natural EV’s engineering, to express the S proteins of SARS-CoV-2 embedded in the EVs, which mimic the virus with its fully native spikes. Immunizations with a two component CoVEVax vaccine, comprising DNA vector (DNAS-EV) primes, allowing in situ production of Spike harbouring EVs, and a boost using S-EVs produced in mammalian cells, trigger potent neutralizing and cellular responses in mice, in the absence of any adjuvants. CoVEVax would be the prototype of vaccines, where the sole exchange of the envelope proteins on EVs leads to the generation of new vaccine candidates against emerging viruses.

  • English
    Authors: 
    Lobbé, Quentin; Chavalarias, David; Delanoë, Alexandre; Ferrand, Gabriel; Cohen-Boulakia, Sarah; Ravaud, Philippe; Boutron, Isabelle;
    Publisher: HAL CCSD
    Country: France

    This paper aims at reconstructing the evolution of all the available COVID-19 vaccines trials extracted from the COVID-NMA database by applying the phylomemy reconstruction process. We visualize the textual contents of 1,794 trials descriptions and explore their collective structure along with their semantic dynamics. We map the continuous progress of the main COVID-19 vaccine platforms from their early-stage trials in February 2020 to their most recent combinations driven by the rise of variants of concern, third dose issues and heterologous vaccinations. This paper brings insights for the global coordination between research teams especially in crisis situations such as the COVID-19 pandemic.

  • English
    Authors: 
    Becher, Michael; Longuet Marx, Nicolas; Pons, Vincent; Brouard, Sylvain; Foucault, Martial; Galasso, Vincenzo; Kerrouche, Éric; León Alfonso, Sandra; Stegmueller, Daniel;
    Publisher: HAL CCSD
    Country: France
  • Open Access
    Authors: 
    Cheikh Talla; Cheikh Loucoubar; Jerlie Loko Roka; Aliou Barry; Seynabou Ndiaye; Maryam Diarra; Oumar Faye; Moussa Dia; Adama Tall; Oumar Ndiaye; +14 more
    Publisher: Elsevier BV
    Country: France

    Background: Senegal reported the first COVID-19 case on March 2, 2020. A nationwide cross-sectional epidemiological survey was conducted to capture the true extent of COVID-19 exposure. Methods: Multi-stage random cluster sampling of households was carried out between October 24 and November 26, 2020, at the end of the first wave of COVID-19 transmission. Anti-SARS-CoV-2 antibodies (IgG and/or IgM) were screened using three distinct ELISA assays. Adjusted prevalence for the survey design were calculated for each test separately, and thereafter combined. Crude, adjusted prevalence based on tests performances and weighted prevalence by sex-age strata were estimated to assess the seroprevalence. Findings: Of the 1,463 participants included in this study, 58·8% were women and the mean age of participants was 29·2 years (range 0·25–82·0). The national seroprevalence was estimated at 28 . 4% (95% CI: 26·1-30·8). There was substantial regional variability. Four regions recorded the highest seroprevalence: Ziguinchor (56·7%), Sedhiou (48·0%), Dakar (44·0%) and Kaolack (32·7%) whereas, Louga (11·1%) and Matam (11·2%), located in the Center-North, were less impacted in our analysis. All age groups were impacted and the prevalence of SARS-CoV-2 was comparable in symptomatic and asymptomatic groups. We estimated 4,744,392 SARS-CoV-2 (95% CI: 4,360,164 – 5,145,327) potential infected in Senegal compared to 16,089 COVID-19 RT-PCR laboratory-confirmed cases reported at the time of the survey. Interpretation: These results provide an estimate of SARS-CoV-2 virus dissemination in the Senegalese population. Preventive and control measures need to be reinforced in the country and especially in the south border regions. Funding Information: This work was supported by US Centers for Disease Control and Prevention (CDC), the Senegalese Ministry of Health, the Senegalese National Statistics and Demography Agency (ANSD), the WHO Unity program and the COVID-19 Task-force of the International Pasteur Institute Network (IPIN, REPAIR project). Declaration of Interests: We declare no competing interests. Ethics Approval Statement: All participants have consented to participate in the study. For people younger than 18 years, a legal representative provided informed consent. The study was approved by the Senegalese National Ethics Committee for Research in Health (reference number N°0176/MSAS/DPRS/CNERS, 10 October 2020).

  • English
    Authors: 
    Hua, Ping;
    Publisher: HAL CCSD
    Country: France

    By using panel data of 15 Chinese manufacturing industries over the 2005-2014 period from OECD TiVA and WIOD databases, the impact of China's GVCs participation on labor productivity is estimated. We find that while the productivity elasticity of the share of sector's foreign value added relative to sector's exports known as sector backward linkages is negative, that relative to China's gross exports named structure backward linkage is positive. As the annual average growth rates of both backward linkages are negative, China's backward linkages have contributed to productivity growth of 6.41% per year on average. We find that the positive productivity elasticity of the share of domestic intermediate goods embodied in exports of third countries relative to sector's exports, named sector forward linages together with a positive annual average growth rate, and that relative to China's exports named structure forward linkages together with a negative annual average growth rate, have increased productivity of 1.97% per year on average. We find finally that GVCs position is improved from 0.3 in 2005 to 0.7 in 2014. China's GVCs participation exerted positive productivity effects via optimizing resource allocation inside sectors towards more efficiency ones, via moving up from low productivity backward linkages to higher productivity forward linkages and via improving its position. This diminished the risk to be entrenched in low-profitability low productivity growth GVCs activities in China. However, the productivity contribution of backward linkages 3 times higher than that of forward linkage suggests that the future positive productivity impact of GVCs moving up may be much more difficult in a less favorable context (trade war between China and USA, reindustrialization and trade protection related to Covid-19 for example).

  • French
    Authors: 
    Mondello, Gérard;
    Publisher: HAL CCSD
    Country: France

    La pandémie de Covid-19 a bouleversé non seulement l'économie de la plupart des pays, mais aussi le domaine scientifique médical. Les opinions publiques se sont immiscées dans les choix des essais thérapeutiques comme le montrent les controverses autour des protocoles utilisant l'hydroxychloroquine. Le choix du public pour ces traitements est expliqué comme l'application d'un "pari de Pascal". Cet article analyse la formation du système de croyance des individus en appliquant la théorie de l'ambiguïté et la théorie de l'entropie d'information. Il montre que les choix du public sont le fruit de stratégies communication choisies par les promoteurs de tel ou tel traitement.

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