/articles

  • Une modélisation pour limiter la transmission des maladies infectieuses dans les aéroports et les gares - Salle de presse de l’Inserm
    https://presse.inserm.fr/une-modelisation-pour-limiter-la-transmission-des-maladies-infectieuses-dans-les-aeroports-et-les-gares/66702


    Le modèle s’intéresse au cas de Heathrow à Londres.
    © Unsplash

    Dans les lieux à forte densité de population, comme dans les aéroports ou les gares, la distanciation sociale peut difficilement être maintenue et le risque de transmission des maladies infectieuses est accru. Afin de réduire ce risque, il est essentiel de mieux comprendre les dynamiques de transmission dans ces espaces et les mesures d’atténuation efficaces qui peuvent être mises en place à moindre coût. C’est l’objectif d’un modèle mathématique développé par des équipes de l’Inserm et de Sorbonne Université à Institut Pierre Louis d’épidémiologie et de santé publique avec l’Institut espagnol CSIC-IFISC.

    En prenant l’exemple de l’aéroport de Heathrow à Londres et de maladies comme la grippe H1N1 et la Covid-19, ce modèle permet d’identifier les lieux où le risque de transmission est le plus grand au sein d’espaces à forte densité de population. En ciblant uniquement ces lieux avec des mesures comme la filtration de l’air ou l’utilisation de lampe Far-UVC, les scientifiques montrent aussi qu’il est possible de réduire les contaminations de manière significative. Les résultats complets sont publiés dans Nature Communications.

    • l’article original

      Spatial immunization to abate disease spreading in transportation hubs | Nature Communications
      https://www.nature.com/articles/s41467-023-36985-0


      Heatmap showing the cells in the airport area in which contagions occur when running the SIR model. In a, after one day of simulation and in b after two days. Color code normalized for each period considered.

      Abstract
      Proximity social interactions are crucial for infectious diseases transmission. Crowded agglomerations pose serious risk of triggering superspreading events. Locations like transportation hubs (airports and stations) are designed to optimize logistic efficiency, not to reduce crowding, and are characterized by a constant in and out flow of people. Here, we analyze the paradigmatic example of London Heathrow, one of the busiest European airports. Thanks to a dataset of anonymized individuals’ trajectories, we can model the spreading of different diseases to localize the contagion hotspots and to propose a spatial immunization policy targeting them to reduce disease spreading risk. We also detect the most vulnerable destinations to contagions produced at the airport and quantify the benefits of the spatial immunization technique to prevent regional and global disease diffusion. This method is immediately generalizable to train, metro and bus stations and to other facilities such as commercial or convention centers.

  • UN high seas treaty is a landmark – but science needs to fill the gaps
    https://www.nature.com/articles/d41586-023-00757-z

    As the planet warms, the Arctic’s permanent ice cover is melting, and China is planning a shipping route through the Central Arctic #Ocean. This could become a regular passageway for shipping between Asia and Europe within a decade. In the Pacific, mining companies are exploring the deep sea bed for metals that they say are needed for the batteries that will power the coming green-energy transition. But these activities won’t face scrutiny under the treaty, because the treaty’s provisions don’t overrule regulations laid down by the authorities that oversee existing high seas activities. These include the International Maritime Organization, which is responsible for shipping; the International Seabed Authority, which oversees deep-sea mining; and some 17 regional fisheries management organizations tasked with regulating fisheries in various parts of the ocean, including Antarctica. Military activities and existing fishing and commercial shipping are, in fact, exempt from the treaty.

    This means, for example, that the treaty cannot create protected areas in places already covered by fishing agreements, even if that fishing is unsustainable and depleting stocks. This is a gaping hole. [...] Once the treaty becomes law (after it has been ratified in the national parliaments of at least 60 countries), it can demand that proposed ocean activities — such as climate-intervention experiments — are subject to stringent environmental impact assessments. But it cannot do the same for activities already under way.

    Nor will the treaty end current offshore environmental violations. [...]

    Nonetheless, as humanity’s first serious attempt to challenge the carnage that prevails offshore, the high seas treaty is a triumph for diplomacy, particularly at a time when multilateralism is under sustained pressure. At present, just 1% of international waters are protected. That proportion is now set to grow, and this will help to maintain the health of our oceans and stem biodiversity loss. In securing this deal, the international community has given itself a fighting chance of coming good on earlier promises — most recently reiterated under the UN Convention on Biological Diversity — to protect 30% of the ocean by 2030.

    #haute_mer

  • Google Translate : « L’examen par les pairs est au cœur du processus scientifique et de l’avancement professionnel des scientifiques, mais les préjugés à diverses étapes du processus d’examen désavantagent certains auteurs. Ici, nous utilisons les données d’examen par les pairs de 312 740 manuscrits de sciences biologiques dans 31 études pour (1) examiner les preuves des résultats différentiels de l’examen par les pairs en fonction de la démographie des auteurs, (2) évaluer l’efficacité des solutions pour réduire les biais et (3) décrire le paysage actuel de politiques d’examen par les pairs pour 541 revues d’écologie et d’évolution. Nous avons trouvé des résultats d’examen nettement moins bons (par exemple, des taux d’acceptation globaux plus faibles) pour les auteurs dont les affiliations institutionnelles étaient en Asie, pour les auteurs dont la langue principale du pays n’est pas l’anglais et dans les pays avec des indices de développement humain relativement faibles. Nous avons trouvé peu de données évaluant l’efficacité des interventions en dehors de la réduction des préjugés sexistes par le biais d’un examen en double aveugle ou de la diversification des comités d’examen/de rédaction. Malgré les preuves d’écarts de résultats d’examen basés sur la démographie des auteurs, peu de revues mettent actuellement en œuvre des politiques visant à atténuer les biais (par exemple, 15,9 % des revues pratiquaient l’examen en double aveugle et 2,03 % avaient des directives d’examen mentionnant les questions de justice sociale). Le manque d’équité démographique signale un besoin urgent de mieux comprendre et de mettre en œuvre des stratégies d’atténuation des biais fondées sur des données probantes. »

    Peer review perpetuates barriers for historically excluded groups | Nature Ecology & Evolution
    https://www.nature.com/articles/s41559-023-01999-w

    Peer review is central to the scientific process and scientists’ career advancement, but bias at various stages of the review process disadvantages some authors. Here we use peer review data from 312,740 biological sciences manuscripts across 31 studies to (1) examine evidence for differential peer review outcomes based on author demographics, (2) evaluate the efficacy of solutions to reduce bias and (3) describe the current landscape of peer review policies for 541 ecology and evolution journals. We found notably worse review outcomes (for example, lower overall acceptance rates) for authors whose institutional affiliations were in Asia, for authors whose country’s primary language is not English and in countries with relatively low Human Development Indices. We found few data evaluating efficacy of interventions outside of reducing gender bias through double-blind review or diversifying reviewer/editorial boards. Despite evidence for review outcome gaps based on author demographics, few journals currently implement policies intended to mitigate bias (for example, 15.9% of journals practised double-blind review and 2.03% had reviewer guidelines that mentioned social justice issues). The lack of demographic equity signals an urgent need to better understand and implement evidence-based bias mitigation strategies.

  • Fed up and burnt out: ‘quiet quitting’ hits academia

    Many researchers dislike the term, but the practice of dialling back unrewarded duties is gaining traction.

    When Isabel Müller became an assistant professor in 2021, she started working 16 hours a day, 7 days a week. Although nobody expected her to work this much, she says, she couldn’t find a way to fit all her research, teaching and mentoring efforts into fewer hours. But as the first term progressed, Müller realized her pace was unsustainable. She needed to set boundaries if she wanted to continue working in academia: “It took another term, but now I try to stick to some rules.”

    Müller, a mathematician at the American University in Cairo, is not alone in her efforts to redefine her relationship with work by setting limits to protect her mental health and stave off burnout. The desire for work–life balance is nothing new — but the COVID-19 pandemic and its aftermath have brought academic workers a greater appreciation of its importance. Last August, the discussion on how best to achieve work–life balance went viral with a TikTok video about ‘quiet quitting’ — the idea that workers should no longer go above and beyond their job requirements and subscribe to ‘hustle culture’. In academia, that translates into no longer performing unpaid, unrecognized or underappreciated tasks.

    To Müller, quiet quitting describes working hours that allow her to have a life outside her job and to take care of herself. “I really dislike the name. Everybody that’s trying to restrict their hours already feels horrible about it,” says Müller. “Quiet quitting has such a negative connotation; it makes you feel even worse.” Many researchers disdain the term, noting that they’re neither quitting nor being quiet about their desire to create healthier work–life boundaries, prioritize their mental health and reject toxic workplace cultures.

    Nature spoke to Müller and other researchers about how and why they’re resetting their boundaries, and what they want from their employers. Some were respondents to an online Nature poll, which ran from 7 to 15 November last year, to evaluate the prevalence of quiet quitting in scientists, their motivations for doing so and which activities they cut back on most (see ‘Dialling back’).

    Sick of the status quo

    Since the pandemic began, many scientists have reduced their working hours and cut back on extraneous projects and activities. According to Nature’s poll, 75% of the 1,748 self-selected respondents had dialled back their work efforts since March 2020. The vast majority worked in academia (73%); others were in industry (9%), government (8%), clinical roles (4%), non-profit organizations (4%) and other workplaces (3%). Respondents were also at a range of career stages: 19% were master’s or PhD students; 17% were postdoctoral fellows or research associates; 17% were research or staff scientists; 10% were assistant professors; 22% were senior professors or lecturers; 7% were middle or senior management; and 8% were in other positions.

    Nearly half of the respondents had cut back on hours or activities because they did not want to work unpaid overtime (48%), felt their supervisor did not sufficiently recognize their activities (45%), did not have enough time for their personal lives (44%) or were not receiving a financial incentive (44%). Respondents could select more than one reason, which is why percentages don’t add up to 100. However, the main reason researchers said they introduced boundaries was burnout (67%).

    “Individuals have been pushed so hard for so long, that apathy sets in, motivations wane and people are exhausted. No more bringing work home and perpetuating the imbalance between work and home life,” says one anonymous respondent (see ‘What ‘quiet quitting’ means to Nature readers’).

    A student pursuing an experimental-physics PhD in Switzerland who, like one other researcher interviewed, asked to remain anonymous to avoid harm to their career, began dialling back their efforts when they felt burnt out and uninspired. When they started their programme in 2018, they had been highly motivated and brimming with research ideas. As the years progressed, their work received less attention from their supervisor and collaborators. “You don’t feel like you’re contributing to something important,” the student says. “You start to detach yourself from the vision of seeing yourself in that field [in the future].”

    Burnout and lack of appreciation have also led established scientists to step back from their careers. One scientist in a senior management position in government responded in the poll, “People [are] looking to stop taking on the ‘other duties as assigned’ component of their job because they believe they are not adequately compensated or appreciated.”

    A professor who taught medical students in the US midwest also dialled back her efforts once her workload felt like too much. “There came a point where I was exhausted by the demands of my job — not just the hours or workload — but by the culture of the institution and all of the emotional labour that I was performing,” she says. For instance, she spent time counselling students about problems such as domestic violence and mental-health issues, despite not having training in these areas. In response to the exhaustion, she shortened her working days from 12 hours to 8 on average, avoided going to campus when it was not required and pulled back from optional activities.

    But doing so did not make her feel better. “I never wanted to be anything other than a professor,” she says. “I felt like I was failing on every front because the demands were so excessive.”
    Culling duties

    In our poll, researchers revealed several ways that they have cut back their work efforts, to help them find a more sustainable work–life balance. Nearly two-thirds of investigators and administrative staff who responded said they had reduced their participation at conferences, and more than half have dialled back their peer-review efforts. Nearly half of senior researchers also reported limiting their committee memberships. By contrast, nearly one-quarter of early-career researchers said they had reduced their efforts in mentoring, diversity, equity and inclusion and in outreach, and one-fifth had reduced their efforts in teaching. More than one-quarter of early-career researchers commented that they had reduced their efforts in other ways, largely by focusing on fewer side projects and collaborations and limiting working hours.

    Early-career scientist Ryan Swimley set balanced work habits starting with his first industry job. After earning a bachelor’s degree from Montana State University in Bozeman, he took a position as an analytical-chemistry technician at Nature’s Fynd, a small company in Bozeman that makes fungus-based, vegan protein substitutes. He went from working up to 16 hours a day, spread among classes, research and studying, to a more regular 9-to-5 schedule at the company. “My mental health is better now. I get to figure out what hobbies I want to do outside of work and pursue them,” he says.

    Scientists are also cutting back on activities that don’t contribute to their own career growth or receive appreciation. “I’m more selective now,” says Jeroen Groeneveld, a palaeoceanographer at National Taiwan University in Taipei. “This month, I have two grant-proposal deadlines, so I’m not going to accept any requests to peer review other journal articles,” he says. (He is far from alone — earlier this month, Nature reported that peer-reviewer fatigue is at an all-time high.)

    Groeneveld studies foraminifera, single-celled organisms whose calcite shells can be preserved in marine sediments and used to reconstruct past environmental conditions. Before August 2022, he had spent a lot of time preparing and analysing samples for other researchers in his field. Now, instead, he invites them to his laboratory to learn the techniques themselves. “That is also a form of quiet quitting in the sense that it’s not saying yes to everything any more,” he says. Doing so not only saves Groeneveld time, but also establishes his lab as a place for learning new methods and for collaboration.

    Müller, the medical educator and other scientists have improved their work–life balance by not responding to e-mails or messages from students at night or weekends. Müller advocates for not scheduling exams during weekends, because it’s more inclusive for those with care responsibilities. “I try to tell my students and the other instructors, if it doesn’t fit into five days, it’s just too much.”
    More-humane workplaces

    Although scientists can restructure their own relationships with work, many argue that institutions should do more to address the conditions driving burnout in the first place. “This idea that you have to be working 24 hours a day, 365 days a year, has got to change,” says the medical educator. “There’s so little acknowledgement that people have difficult, complicated lives outside of work.” She suggests that US academic institutions provide employees with more sick days, paid parental and care leave, subsidized care for children and ageing relatives, flexible tenure clocks and more automatic sabbatical breaks. Institutions could also hire more teaching, lab and administrative-support staff members to help spread out heavy workloads.

    Institutions and companies can provide better support for overwhelmed scientists by checking in with employees about their workloads and stress levels. Swimley notes that his direct supervisor asks about his bandwidth to take on new projects, and understands if he needs more time to complete his work. The experimental-physics student suggests that supervisors who don’t have the capacity to offer guidance or career support should reconsider bringing new students into their group. “Don’t treat people like they’re expendable,” the student says.

    Nearly half of the respondents said they have dialled back efforts because of a lack of appreciation from supervisors, or a lack of financial compensation. “I think the main thing universities can do is change their priorities to take care of employees and create a workplace where people feel appreciated and seen,” Müller says. Even simple but personalized e-mail recognition of recent publications, grant successes or positive student evaluations from supervisors would go a long way, she adds.

    When scientists set their own boundaries, it not only improves personal well-being, but also signals to peers that such limits are acceptable and healthy, says Müller. “It does not mean I’m lazy if I don’t want to answer e-mails on the weekend,” she says. “I hope it becomes the new normal to say, ‘My life matters. My work is an important part, but I decide what my life looks like, not my employer.’”

    For a few scientists, quiet quitting can progress into quitting academia altogether. In July 2021, the tenured medical educator left her institution for a position with a non-profit organization, where she still uses her education and publishing skills. Part of her new job involves facilitating meetings with subject-matter specialists, working with authors and copy-editing educational materials. “I’m constantly learning new things,” she says.

    In addition, she feels appreciated by her colleagues and grateful for her improved work–life balance. “I work 100% remote from 8 a.m. to 4 p.m. At the end of the day, I shut the laptop and I walk away. No more working nights. No more working weekends,” she describes.

    Her new schedule has freed up time for her to engage more with members of her professional community. She now serves in a women’s mentoring network and facilitates a monthly mentorship group for people interested in careers outside academia.

    Although she says the transition out of academia wasn’t easy — she was concerned about how her peers would view her decision — she found that almost everyone was supportive. “I’ve gotten lots of back-door inquiries and quiet messages from people who are like, ‘How did you do that?’”

    https://www.nature.com/articles/d41586-023-00633-w

    #burn-out #conditions_de_travail #travail #université #ESR #enseignement_supérieur #santé_mentale #charge_de_travail

    ping @_kg_

  • The impact of satellite trails on Hubble Space Telescope observations | Nature Astronomy
    https://www.nature.com/articles/s41550-023-01903-3

    The recent launch of low Earth orbit satellite constellations is creating a growing threat for astronomical observations with ground-based telescopes that has alarmed the astronomical community. Observations affected by artificial satellites can become unusable for scientific research, wasting a growing fraction of the research budget on costly infrastructures and mitigation efforts. Here we report the first measurements, to our knowledge, of artificial satellite contamination on observations from a low Earth orbit made with the Hubble Space Telescope. With the help of volunteers on a citizen science project (www.asteroidhunter.org) and a deep learning algorithm, we scanned the archive of Hubble Space Telescope images taken between 2002 and 2021. We find that a fraction of 2.7% of the individual exposures with a typical exposure time of 11 minutes are crossed by satellites and that the fraction of satellite trails in the images increases with time. This fraction depends on the size of the field of view, exposure time, filter used and pointing. With the growing number of artificial satellites currently planned, the fraction of Hubble Space Telescope images crossed by satellites will increase in the next decade and will need further close study and monitoring.

  • COVID pill is first to cut short positive-test time after infection
    https://www.nature.com/articles/d41586-023-00548-6

    The antiviral #ensitrelvir, which is not approved in the United States, shortens symptoms in people with mild COVID and might reduce risk of long #COVID — but more data are needed.

    Covid-19 : l’ensitrelvir, un nouvel antiviral japonais prometteur évalué aux États-Unis | Le Quotidien du Médecin
    https://www.lequotidiendumedecin.fr/specialites/infectiologie/covid-19-lensitrelvir-un-nouvel-antiviral-japonais-prometteur-e

    Cet essai, randomisé contre placebo, recrutera environ 1 500 patients hospitalisés à la suite d’une infection sévère par le Sars-CoV-2. Le premier jour, les patients traités recevront trois doses de 125 mg, puis une dose par jour pendant quatre jours. Le suivi total sera de 60 jours.

  • Les villes côtières américaines sous-estiment les risques que pose la #montée_des_eaux
    https://www.courrierinternational.com/article/climat-les-villes-cotieres-americaines-sous-estiment-les-risq

    “D’après une étude, plus de la moitié des villes côtières américaines sous-estiment la hausse du niveau de la mer que le réchauffement climatique pourrait provoquer dans leur région”, rapporte Nature. Les chercheurs, qui publient leurs travaux dans Earth’s Future, se sont intéressés à la façon dont les projections scientifiques sont prises en compte concrètement dans les plans d’aménagement des territoires.

    Source :
    US coastal communities underestimate the danger posed by rising seas
    https://www.nature.com/articles/d41586-023-00384-8

    #etats-unis #climat

  • Study: 15 million people live under threat of glacial floods | AP News
    https://apnews.com/article/floods-science-india-peru-pakistan-51368bb5eef49a240d3d466775e34ed6

    As #glaciers melt and pour massive amounts of water into nearby lakes, 15 million people across the globe live under the threat of a sudden and deadly outburst flood, a new study finds.

    More than half of those living in the shadow of the disaster called glacial lake outburst floods are in just four countries: India, Pakistan, Peru and China, according to a study in Tuesday’s Nature Communications. A second study, awaiting publication in a peer-reviewed journal, catalogs more than 150 glacial flood outbursts in history and recent times.

    It’s a threat Americans and Europeans rarely think about, but 1 million people live within just 6 miles (10 kilometers) of potentially unstable glacial-fed lakes, the study calculated.

    #source : Glacial lake outburst floods threaten millions globally | Nature Communications
    https://www.nature.com/articles/s41467-023-36033-x

    #inondations

  • Glacial lake floods threaten communities in Asia, South America | Reuters
    https://www.reuters.com/business/environment/glacial-lake-floods-threaten-communities-asia-south-america-2023-02-07/?taid=63e2a46a58449200011e8733
    https://www.reuters.com/resizer/vqbGkUePiVpll2V4FeLJN0LFFTM=/1200x628/smart/filters:quality(80)/cloudfront-us-east-2.images.arcpublishing.com/reuters/BKHZDOIYXJP2PELM3EDMTZG4QM.jpg

    Melting mountain glaciers pose a growing flood risk to some 15 million people around the world, researchers said in a report published on Tuesday, with communities in Asia facing the biggest danger.

    Runoff from melting glaciers often pools in shallow lakes, held back by rocks and debris. The risk comes when a lake overfills, bursting through its natural barrier and sending a torrent of water rushing down mountain valleys.

    Scientists have assessed for the first time how many people globally are at risk from these floods, finding that more than half of vulnerable populations live in India, Pakistan, China, and Peru.

    Glacial lake outburst floods threaten millions globally
    https://www.nature.com/articles/s41467-023-36033-x

    #climat #montagne #glacier #fonte #inondation

  • How quickly does COVID immunity fade? What scientists know
    https://www.nature.com/articles/d41586-023-00124-y

    New evidence suggests that ‘hybrid’ immunity, the result of both #vaccination and a bout of #COVID-19, can provide partial protection against #reinfection for at least eight months1. It also offers greater than 95% protection against severe disease or hospitalization for between six months and a year after an infection or vaccination, according to estimates from a meta-analysis2. Immunity acquired by booster vaccination alone seems to fade somewhat faster.

    But the durability of immunity is much more complex than the numbers suggest. How long the immune system can fend off #SARS-CoV-2 infection depends not only on how much immunity wanes over time but also on how well immune cells recognize their target. “And that has more to do with the virus and how much it mutates,” says Deepta Bhattacharya, an immunologist at the University of Arizona College of Medicine in Tucson. If a new #variant finds ways to escape the existing immune response, then even a recent infection might not guarantee protection.

    […]

    Thålin understands how frustrating the caveats and uncertainty can be, but says that researchers aren’t likely to pin down an answer anytime soon. “The virus is evolving so fast,” she says. “What’s true today might not be true tomorrow.”

    #immunité

  • LivWell: a sub-national Dataset on the Living Conditions of Women and their Well-being for 52 Countries | Scientific Data
    https://www.nature.com/articles/s41597-022-01824-2

    Abstract
    Data on women’s living conditions and socio-economic development are important for understanding and addressing the pronounced challenges and inequalities faced by women worldwide. While such information is increasingly available at the national level, comparable data at the sub-national level are missing. We here present the LivWell global longitudinal dataset, which includes a set of key indicators on women’s socio-economic status, health and well-being, access to basic services and demographic outcomes. It covers 447 regions in 52 countries and includes a total of 265 different indicators. The majority of these are based on 199 Demographic and Health Surveys (DHS) for the period 1990–2019 and are complemented by extensive information on socio-economic and climatic conditions in the respective regions. The resulting dataset offers various opportunities for policy-relevant research on gender inequality, inclusive development and demographic trends at the sub-national level.

    […]
    In this article, we present LivWell4: a global longitudinal dataset at the sub-national level, which is mainly derived from Demographic and Health Survey (DHS) data5 ( https://dhsprogram.com/data ). LivWell is based on the answers of millions of women and collected in 199 DHS surveys in 52 countries. The microdata were aggregated to the sub-national regional level (geo admin 1). The resulting macro-level dataset covers 447 harmonized sub-national regions over a 30-year period from 1990 to 2019. It includes 114 indicators on women’s status and wealth, education, household characteristics, (reproductive) health, fertility and infant health (Fig. 1, Supplementary Table 1). In addition, we included 20 indicators on domestic violence and decision-making power which are particularly difficult to obtain from other sources.
    […]
    The LivWell dataset consists of 5 groups of indicators (Fig. 1 and Supplementary Table 1 and 2 for a full list of indicators). The first group of indicators is based on individual level DHS data (103 indicators) and contains information on women’s living conditions, decision making power, reproductive health, fertility, and issues related to domestic violence. The second and third group of indicators are also based on DHS data and reflect composite measures of child mortality and household wealth. The fourth group of indicators includes regional socio-economic indicators (HDI and GDP per capita) derived from external gridded data provided by Kummu et al.9. Finally, the fifth group of indicators reflects the environmental and climatic conditions in a region and is derived from the gridded climate data provided by the CRU of the University of East Anglia.

  • SARS-CoV-2 variant biology : immune escape, transmission and fitness | Nature Reviews Microbiology
    https://www.nature.com/articles/s41579-022-00841-7

    #SARS-CoV-2 shows a complicated relationship among virus antigenicity, transmission and virulence, which has unpredictable implications for the future trajectory and disease burden of COVID-19.

  • #Long_COVID: major findings, mechanisms and recommendations | Nature Reviews Microbiology
    https://www.nature.com/articles/s41579-022-00846-2

    The incidence is estimated at 10–30% of non-hospitalized cases, 50–70% of hospitalized cases and 10–12% of vaccinated cases.

    Long COVID is associated with all ages and acute phase disease severities, with the highest percentage of diagnoses between the ages of 36 and 50 years, and most long COVID cases are in non-hospitalized patients with a mild acute illness, as this population represents the majority of overall COVID-19 cases.

    #post_covid #covid_long

  • Make electric vehicles lighter to maximize climate and safety benefits [octobre 2021]
    https://www.nature.com/articles/d41586-021-02760-8

    One issue that has received too little attention, in our view, is the increasing weight of vehicles. Pick-up trucks and sport utility vehicles (SUVs) now account for 57% of US sales, compared with 30% in 1990. The mass of a new vehicle sold in the United States has also risen — cars, SUVs and pick-up trucks have gained 12% (173 kilograms), 7% (136 kg) and 32% (573 kg), respectively, since 1990. That’s equivalent to hauling around a grand piano and pianist. Similar trends are seen elsewhere in the world.

    Electrifying vehicles adds yet more weight. Combustible, energy-dense petroleum is replaced by bulky batteries. And the rest of the vehicle must get heavier to provide the necessary structural support1. The electric F-150 weighs 700 kg more than its petrol-powered predecessor. Smaller electric cars are heavier than their petrol equivalents, too.

    Why does this matter? First and foremost is safety. The likelihood of passengers being killed in a collision with another vehicle increases by 12% for every 500-kg difference between vehicles. [...] Pedestrians will also be at risk. If US residents who switched to SUVs over the past 20 years had stuck with smaller cars, more than 1,000 pedestrian deaths might have been averted, according to one study.

    Heavier vehicles also generate more particulate pollution from tyre wear. They require more materials and energy to build and propel them, adding to emissions and energy use.

    How big a problem is this extra weight? A rough comparison between mortality costs and climate benefits shows that it is significant. Under the energy systems operating in most countries today, the cost of extra lives lost from a 700-kg increase in the weight of an electrified truck rivals the climate benefits of avoided greenhouse-gas emissions.

    Parmi les solutions proposées : taxer les véhicules en fonction de leur poid et faire en sorte que les gains d’efficacité des batteries servent à réduire leur taille plutôt qu’à en augmenter la puissance et l’autonomie.
    #transport #voitures_électriques

  • #SARS-CoV-2 infection and persistence in the human body and brain at autopsy | Nature
    https://www.nature.com/articles/s41586-022-05542-y

    Abstract

    Coronavirus disease 2019 (COVID-19) is known to cause multi-organ dysfunction during acute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some patients experiencing prolonged symptoms, termed post-acute sequelae of SARS-CoV-2. However, the burden of infection outside the respiratory tract and time to viral clearance are not well characterized, particularly in the brain

    Here we carried out complete autopsies on 44 patients who died with COVID-19, with extensive sampling of the central nervous system in 11 of these patients, to map and quantify the distribution, replication and cell-type specificity of SARS-CoV-2 across the human body, including the brain, from acute infection to more than seven months following symptom onset.

    We show that SARS-CoV-2 is widely distributed, predominantly among patients who died with severe COVID-19, and that virus replication is present in multiple respiratory and non-respiratory tissues, including the brain, early in infection. Further, we detected persistent SARS-CoV-2 RNA in multiple anatomic sites, including throughout the brain, as late as 230 days following symptom onset in one case. Despite extensive distribution of SARS-CoV-2 RNA throughout the body, we observed little evidence of inflammation or direct viral cytopathology outside the respiratory tract . Our data indicate that in some patients SARS-CoV-2 can cause systemic infection and persist in the body for months.

  • La #dette_immunitaire : argument utile ou réalité scientifique ? | Le Quotidien du Médecin
    https://www.lequotidiendumedecin.fr/specialites/infectiologie/la-dette-immunitaire-argument-utile-ou-realite-scientifique

    CONTRIBUTION - La théorie de la « dette immunitaire » est née en 2021, dans un article d’opinion publié dans la revue « Infectious Diseases Now » par une équipe de pédiatres français. Elle a été ensuite reprise sur les plateaux télé et par les politiques, afin de justifier l’ampleur de l’épidémie de bronchiolite de l’automne 2022. L’hypothèse paraît séduisante, mais est-elle réellement fondée et que recouvre-t-elle exactement  ? Un groupe de médecins et de chercheurs remet en cause le concept.

    Au cours des deux premiers hivers de la crise #Covid-19, dans l’hémisphère nord, les cas d’infections par la grippe, le virus respiratoire syncytial (VRS) ou d’autres pathogènes respiratoires, ont beaucoup diminué ou leur temporalité a été modifiée, par comparaison aux années pré-pandémiques. C’est un fait, autant la protection conférée par le masque que les mesures de prévention contre les infections respiratoires ont rapidement atténué sa mortalité initiale de 1 % du Covid-19.

    La « dette immunitaire » est présentée par ses inventeurs comme la conséquence d’un « défaut de stimulation » du système immunitaire en l’absence d’agents pathogènes. D’être trop « inactif », il s’affaiblirait tel un muscle non sollicité, et la dette deviendrait la conséquence « logique » des mesures sanitaires (masques, distanciation, couvre-feu, etc.). Ses promoteurs affirment donc que le système immunitaire serait comptable d’une dette à l’égard des agents infectieux, se traduisant par d’importantes vagues épidémiques une fois les mesures sanitaires levées, d’où la recrudescence des bronchiolites, infections à streptocoque, etc.

    Cette dette concernerait l’immunité adaptative spécifique et l’immunité innée non spécifique. Le premier phénomène, appelé en réalité immunity gap (lacune d’immunité), et connu depuis les années 70, repose sur des mécanismes bien décrits et fait largement consensus. Si une proportion d’individus au sein d’une population est immunitairement naïve vis-à-vis d’un pathogène, cela expose toute la population à l’émergence d’une épidémie avec explosion du nombre de cas de la maladie associée, non pas à cause d’une augmentation de la virulence du pathogène, ni d’un « affaiblissement » du système immunitaire des individus naïfs, mais parce que le pathogène se propage facilement en l’absence de mémoire immunitaire spécifique (aussi en cas de couverture vaccinale insuffisante ou persistance limitée de la mémoire spécifique). Or, la théorie de la dette n’est pas équivalente à l’immunity gap, car ses auteurs postulent, sans le démontrer, un affaiblissement du système immunitaire inné (et non adaptatif) à l’échelle individuelle et non populationnelle.

    Non fondée scientifiquement et contreproductive

    Le concept « sexy » de dette immunitaire ne fait pas consensus car il ne repose sur aucune preuve épidémiologique ou expérimentale et souffre de nombreuses incohérences : 1) Le système immunitaire est actif en permanence, même en l’absence de pathogènes (immunité constitutive). Les pathogènes lui échappant suscitent en revanche une activation plus importante (inflammation), limitée dans le temps car elle produit des effets délétères. 2) Les systèmes immunitaires inné et adaptatif sont déjà fonctionnels in utero, sans avoir préalablement rencontré de pathogènes. 3) Le système immunitaire inné reconnaît les organismes étrangers par leurs caractéristiques moléculaires conservées, y compris pour l’immense diversité des non-pathogènes du microbiote, qui stimulent donc aussi le système immunitaire. 4) Personne n’a vécu depuis février 2020 dans un environnement aseptique : des micro-organismes partageant les mêmes caractéristiques sont partout (environnement, air, objets manipulés, personnes, sur et dans notre nourriture, etc.). 5) Les centaines de millions d’individus infectés au SARS-CoV-2 depuis 3 ans, dont 28 millions rien qu’en France en 2022, et les réinfections, témoignent de l’impossibilité d’une « non-stimulation » virale généralisée, à moins de supposer que le SARS-CoV-2 ne stimulerait pas le système immunitaire. 6) Les pays dans lesquels les mesures de protection n’ont pas été généralisées ne devraient pas connaître de « dette ». Or, la recrudescence de cas de bronchiolites liés à une infection virale (VRS, SARS-CoV-2, metapneumovirus, adénovirus, etc.) est également enregistrée dans les pays sans aucune politique de santé publique forte en faveur du port du masque chez les enfants (UK, Suède, certains États US).

    Recourir au lexique financier de la dette qu’il faut payer un jour ou l’autre est une façon de réinventer un phénomène immunologique connu (immunity gap) afin de lui adjoindre une double dimension, financière et in fine surtout morale, ce qui n’appartient pas au champ scientifique : la faute serait d’avoir eu recours à des mesures de prévention non pharmaceutiques. Or, cette théorie est précisément promue par des opposants de la première heure à ces mesures dans les écoles, les mêmes qui ont initialement été très réticents à la vaccination des enfants, car leur infection massive était supposée favoriser l’immunité de groupe.

    La théorie non démontrée de la dette immunitaire paraît donc actuellement surtout ad hoc et opportuniste, susceptible d’éviter de prendre des mesures peu populaires en une période où règnent l’oubli et le déni de l’épidémie.

    Des études scientifiques récentes (ici# ou là##) s’intéressent actuellement à la perturbation du système immunitaire suite au Covid-19, hypothèse encore peu évoquée hors du champ scientifique, ce qui pose question et doit tous nous alerter sur la nécessité de nous protéger en promouvant les mesures non pharmaceutiques pragmatiques et simples à mettre en œuvre, telles que le port du masque, l’amélioration de la qualité de l’air en zones à risques, ou l’élargissement des possibilités de travail distanciel en cas de symptômes, afin de protéger la population.

    # https://www.nature.com/articles/s41590-021-01113-x

    ##
    https://www.frontiersin.org/articles/10.3389/fimmu.2022.1034159/full

  • Les scientifiques ont découvert pourquoi le méthane a connu une hausse spectaculaire dans l’atmosphère en 2020
    https://www.lemonde.fr/planete/article/2022/12/14/les-scientifiques-ont-decouvert-pourquoi-le-methane-a-connu-une-hausse-spect

    Les fortes augmentations de ce gaz à effet de serre très puissant sont liées à la baisse de la pollution de l’air et à la progression des émissions des zones humides. Deux causes qui risquent d’aggraver encore le dérèglement climatique.

  • Degrowth can work — here’s how science can help
    https://www.nature.com/articles/d41586-022-04412-x

    The question is no longer whether growth will run into limits, but rather how we can enable societies to prosper without growth, to ensure a just and ecological future

    #services_publics #réduire_les_inégalités #économie_d'énergie #décarbonation #économiser_les_ressources #réduire_la_consommation

  • How a dangerous stew of air #pollution is choking the United States
    https://www.nature.com/articles/d41586-022-04333-9

    The country has some of the strongest environmental regulations in the world, and has made significant progress cleaning its skies since the 1970s. Regulations such as the Clean Air Act drastically cut levels of air pollution — including lead, sulfur dioxide, nitrogen dioxide, ozone and fine particles — from vehicles, power plants, factories and other sources. But the air-quality success story has been swamped in the past decade by staggering environmental shifts due to a warming climate.

    Beyond spurring forest fires, climate change has also made the region more susceptible to droughts that dry out soils and expose lake beds, leading to vast plumes of airborne dust. Adding to the problem are emissions from agriculture, transportation and fossil-fuel development in California and the southwestern states, which lead to high levels of ground-level ozone and other types of pollution. Some 40% of Americans — more than 137 million people, mostly in the West — are living in places that have unhealthy levels of particle pollution or ozone, according to the American Lung Association’s State of the Air 2022 report.

    The changes are putting tens of millions of people at risk — not only in the western states, but across the country. “The Clean Air Act was not designed for today’s sources of pollution,” says Marshall Burke, an Earth-systems scientist at Stanford University in California. Amid all these changes, researchers are struggling to find ways to tackle the West’s harmful air.

    #climat #états-unis