Daily Chart - How long can the novel coronavirus survive on surfaces and in the air ? | Graphic detail | The Economist
▻https://www.economist.com/graphic-detail/2020/03/19/how-long-can-the-novel-coronavirus-survive-on-surfaces-and-in-the-air?fsrc=scn/tw/te/bl/ed/dailycharthowlongcanthenovelcoronavirussurviveonsurfacesandintheairgraphi
#contamination
Je vais pas m’inscrire pour voir le reste.
A new study shows that SARS-CoV-2 can linger in the air for hours and on some materials for days
AT A TIME when many people have taken to washing hands and sanitising the objects they hold dear—frequently—a pesky question has loomed. How long does the SARS-CoV-2 virus stick around? A new paper in the New England Journal of Medicine, one of the first to examine the lifespan of the virus on common surfaces, offers some answers.
Like the common cold, covid-19 spreads through virus-laden droplets of moisture released when an infected person coughs, sneezes or merely exhales. A team of researchers, including scientists from America’s National Institute of Allergy and Infectious Diseases, simulated how an infected individual might spread the virus in the air and on plastic, cardboard, stainless steel and copper. They then measured how long the virus remained infectious in those environments.
They found that SARS-CoV-2 stays more stable on plastic and steel than on cardboard or copper. Traces of the virus were detected on plastic and steel up to three days after contamination. SARS-CoV-2 survived on cardboard for up to one day. On copper, the most hostile surface tested, it lasted just four hours (see chart). In the air, the team found that the virus can stick around for at least three hours. In the air, as elsewhere, the virus’s ability to infect people diminished sharply over time. In the air, for instance, its estimated median half-life—the time it takes for half of the virus particles to become inactive—was just over an hour. And the levels of the virus that do remain in the air are not high enough to pose a risk to most people who are not in the immediate vicinity of an infected person.
These findings are likely to assuage some fears. Homebound consumers worried about contagion from cardboard delivery boxes may have less to worry about the next time Amazon rings (unless they are used to same-day delivery). At the same time, the findings will amplify concerns about airborne transmission, which some experts had not considered possible. The research may change the way medical workers interact with infected patients, who with close contact may transmit the virus onto protective gear.
Why the virus can survive longer on some surfaces rather than others still remains something of a mystery. Maybe it has to do with the consistency of the object playing host to the virus. Cardboard, of course, is much more porous than steel, plastic or copper. But the authors noted that there was more variation in their experiment for cardboard than for other surfaces, and the results should be interpreted with caution. No doubt consumers are used to treating their surroundings that way by now.
Un essai randomisé contrôlé du Remdesivir contre le Covid-19 : effet légèrement positif.
Remdesivir for the Treatment of Covid-19 — Preliminary Report
►https://www.nejm.org/doi/full/10.1056/NEJMoa2007764
A total of 1063 patients underwent randomization. The data and safety monitoring board recommended early unblinding of the results on the basis of findings from an analysis that showed shortened time to recovery in the remdesivir group. Preliminary results from the 1059 patients (538 assigned to remdesivir and 521 to placebo) with data available after randomization indicated that those who received remdesivir had a median recovery time of 11 days (95% confidence interval [CI], 9 to 12), as compared with 15 days (95% CI, 13 to 19) in those who received placebo (rate ratio for recovery, 1.32; 95% CI, 1.12 to 1.55; P<0.001). The Kaplan-Meier estimates of mortality by 14 days were 7.1% with remdesivir and 11.9% with placebo (hazard ratio for death, 0.70; 95% CI, 0.47 to 1.04). Serious adverse events were reported for 114 of the 541 patients in the remdesivir group who underwent randomization (21.1%) and 141 of the 522 patients in the placebo group who underwent randomization (27.0%).
Wrong but Useful — What #Covid-19 Epidemiologic Models Can and Cannot Tell Us | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMp2016822?source=nejmfacebook&medium=organic-social
Comme en France avec le #Tocilizumab (►https://seenthis.net/messages/848280) aux Etats-Unis on attend toujours les résultats définitifs du traitement par le #Remdesivir (▻https://seenthis.net/messages/845382#message849124)
Where’s the data ? Now is no time to sit on Covid-19 trial results
▻https://www.statnews.com/2020/05/13/wheres-the-data-in-a-pandemic-now-is-no-time-to-sit-on-covid-19-trial-resu
In the absence of full results, we lack further insight into safety or how the drug may work on subsets of patients. And for now, the extent to which remdesivir can prevent deaths – a key metric – is unsettled. Fewer patients died while on the drug than placebo, but the findings were not statistically significant and need further analysis. Fauci, however, insisted “the conclusion will not change.”
Maybe not, but until the data are released, doctors are left with a mix of facts and assumptions.
Résultats définitifs parus récemment
Remdesivir for the Treatment of Covid-19 — Final Report | NEJM
►https://www.nejm.org/doi/full/10.1056/NEJMoa2007764
Concluent à l’efficacité du Remdesivir (avec même moins d’effets secondaires que le placebo)
Serious adverse events were reported in 131 of the 532 patients who received remdesivir (24.6%) and in 163 of the 516 patients who received placebo (31.6%).
Le coronavirus se propage-t-il par voie aérienne ? Publications et désaccords
Par Amélie Poinssot
▻https://www.mediapart.fr/journal/france/290420/le-coronavirus-se-propage-t-il-par-voie-aerienne-publications-et-desaccord
Une nouvelle étude italienne, contestée, a trouvé des traces d’ARN du Covid-19 sur des particules fines à Bergame, la ville de la péninsule la plus touchée par l’épidémie. Une étude américaine montre que le virus peut rester viable trois heures dans l’air. Tour d’horizon des dernières publications scientifiques.
C’est l’impensé des politiques publiques actuelles, et un champ encore largement inexploré. Le Covid-19 pourrait-il se transmettre par voie aérienne ? Jusqu’à présent, seuls les contacts entre individus, gouttelettes humaines (toux, éternuement), et avec des surfaces infectées ont été reconnus par l’Organisation mondiale de la santé (OMS) comme facteurs de transmission du coronavirus. Les mesures sanitaires ont été prises au regard de ces connaissances.
Une étude italienne [1], publiée le 24 avril par la revue MedRχiν, ouvre de nouvelles perspectives et fait le lien avec la pollution atmosphérique. Ce travail provient de la même équipe qui avait mis en évidence, fin mars, que la plaine du Pô – région la plus industrialisée du pays et celle dont la concentration en particules fines a systématiquement dépassé la limite considérée comme acceptable de 50 mg/m³ (pendant la période examinée) – a connu, passé le délai des quatorze jours d’incubation de la maladie, la progression la plus forte du nombre de personnes infectées par le Covid. Elle avait alors émis l’hypothèse que les particules fines ont pu agir comme agent vecteur du virus et accélérer sa propagation, sans toutefois identifier une présence de Covid-19 sur ces particules.
C’est chose faite cette fois-ci. À partir d’échantillons prélevés entre le 21 février et le 13 mars dans l’air de Bergame, la ville italienne la plus touchée par l’épidémie, ces chercheurs ont réussi, selon leurs résultats, à identifier sur certaines particules fines l’ARN du SARS-Cov-2, c’est-à-dire le matériel génétique du virus à l’origine de l’épidémie actuelle. Pour cela, ils ont fait analyser 35 échantillons de PM10 (particules fines d’un diamètre inférieur à 10 micromètres) par le laboratoire de l’université de Trieste et parallèlement par l’hôpital universitaire local : au total, sept d’entre eux ont été testés positifs à l’ARN du virus.
Dans une rue de Paris, le 28 avril 2020. © Mehdi Taamallah / NurPhoto via AFP« C’est la première preuve préliminaire que l’ARN du SARS-Cov-2 peut être présent sur des particules en suspension, suggérant par conséquent que dans des conditions de stabilité atmosphérique et de fortes concentrations de particules fines, le SARS-Cov-2 pourrait créer des groupes avec des particules fines dans l’air et – en réduisant leur coefficient de diffusion – augmenter la persistance du virus dans l’atmosphère », concluent les chercheurs.
Si cette hypothèse était avérée, cela signifierait que les zones denses en particules fines, donc les régions touchées par un fort trafic routier, la pollution industrielle ou encore l’agriculture intensive – trois facteurs réunis dans le cas de Bergame et de la plaine du Pô – favoriseraient la circulation du virus. Autrement dit, qu’il faudrait combattre la pollution tout autant qu’adopter la distanciation sociale pour freiner la propagation de la maladie.
« Cette étude démontre que le virus peut être véhiculé par les particules fines mais on ne sait pas encore combien de temps il peut rester infectant dans l’air, ni si la charge virale est suffisante, explique le radiologue strasbourgeois Thomas Bourdrel, membre du collectif Air Santé Climat. Ce qui est sûr, c’est qu’il ne peut pas y avoir une transmission de la maladie sur plusieurs kilomètres, mais une contamination sur courte distance – quelques dizaines ou centaines de mètres par exemple – en cas de pollution aux particules peut être envisagée. On peut imaginer également que dans un espace confiné chargé en particules comme le souterrain du métro, l’effet “transporteur” des particules pourrait avoir des conséquences importantes. »
Cette étude cependant est à prendre avec des pincettes : elle n’a pas fait l’objet d’évaluation par les pairs, comme il est de règle dans la communauté scientifique ; ce n’est qu’une pré-publication. Le consortium Actris, réseau rassemblant des infrastructures de recherche européennes travaillant sur les aérosols atmosphériques, l’a d’ailleurs pointé dans un communiqué [2].
« Il faut vérifier les procédures et la méthode utilisée, vérifier qu’il n’y a pas eu contamination pendant la manipulation », indique ainsi Jean-François Doussin, professeur de chimie atmosphérique à l’université Paris-Est-Créteil et au CNRS.
Ce chercheur, qui travaille depuis plus de vingt ans sur la pollution, émet par ailleurs de sérieux doutes sur la conclusion de l’étude italienne. D’une part, la détection d’ARN du SARS-Cov-2 sur les particules fines ne donne aucune indication sur la question de savoir si le virus est contaminant ou pas : « On ne sait pas à partir de quelle quantité dans l’air le virus peut être infectieux. » D’autre part, « la probabilité pour que des particules de pollution s’agrègent avec des particules contenant le virus et le fassent voyager est extrêmement faible. Celles-ci n’ont d’ailleurs pas besoin de ces supports pour être transportées. »
Les particules issues de l’évaporation des gouttelettes humaines, poursuit le chercheur, sont en effet susceptibles de véhiculer le virus. « En ce sens, l’aérocontamination est possible, et ce serait alors davantage dans les espaces fermés qu’en extérieur qu’il faudrait être vigilant. Cela pose la question de l’aération des bâtiments. »
Sans vouloir nier le facteur environnement dans l’évolution de la maladie, Jean-François Doussin estime que, si une corrélation entre exposition à la pollution aux particules fines et propagation du Covid-19 était confirmée, c’est aussi du côté de la sensibilisation de l’organisme humain qu’il faudrait chercher, la pollution atmosphérique étant à l’origine de détresse respiratoire chronique et de maladies. « La pollution est responsable de 40 000 à 50 000 décès prématurés en France chaque année », rappelle-t-il.
À l’université Clermont-Auvergne, le physicien Laurent Deguillaume et le microbiologiste Pierre Amato expriment des réserves similaires sur la publication italienne. « C’est une première étude, qui a le mérite d’exister. Mais cela ne signifie pas qu’il y a un lien effectif et démontré entre propagation de l’épidémie et particules de pollution », expliquent ces deux chercheurs, affiliés respectivement au Laboratoire de météorologie physique pour le premier, au CNRS et à l’Institut de chimie de Clermont-Ferrand pour le second. « La survie du virus dans l’air peut dépendre des U.V., de la chaleur, des conditions météorologiques… Elle est très difficile à évaluer. Par ailleurs, détecter l’ARN comme l’a fait cette équipe italienne ne nous dit rien sur les protéines de surface du virus, qui peuvent être détériorées et donc tuer sa virulence, comme sous l’effet du savon. Il faut rester prudent, en attendant de nouvelles études plus robustes. »
Sans que le lien soit établi avec la pollution atmosphérique, plusieurs travaux scientifiques publiés ces dernières semaines sont venus renforcer l’hypothèse d’une propagation du coronavirus par voie aérienne.
Dans The New England Journal of Medecine, une équipe d’une quinzaine de chercheurs issus de différentes universités américaines (parmi lesquelles Princeton) et de l’Institut national américain des allergies et maladies infectieuses, a publié le 16 avril un article [3] faisant état d’une expérience comparée en laboratoire sur la stabilité et la décomposition des deux coronavirus suivant l’environnement dans lequel ils se trouvent (SARS-Cov-1, responsable de la première épidémie en 2002-2003 qui avait fait 349 morts et infecté 5 327 personnes, et SARS-Cov-2).
Résultat, les deux virus présentent des trajectoires similaires : trois heures de viabilité dans l’air, jusqu’à 72 heures de viabilité sur du plastique et de l’acier inoxydable, jusqu’à huit heures de viabilité pour le premier SARS sur du cuivre et du carton ; le deuxième SARS pouvant être viable quant à lui jusqu’à quatre heures sur du cuivre et vingt-quatre heures sur du coton.
« Nos résultats montrent que la transmission de SARS-Covid-2 par des vecteurs et des particules en suspension est plausible, puisque le virus peut rester viable et infectieux dans les aérosols pendant trois heures », conclut l’équipe américaine.
Une autre étude, chinoise celle-ci, vient étayer cette thèse. Publiée le 10 mars [4] par la revue spécialisée bioRχiν puis ce lundi [5] par la célèbre revue scientifique Nature, elle se base sur des échantillons collectés dans deux hôpitaux de Wuhan entre le 17 février et le 2 mars. Au total, 35 échantillons d’aérosol prélevés dans les espaces des différents usagers (patients, équipe médicale, public) ont été analysés. Dans plusieurs d’entre eux, la présence du virus a été diagnostiquée. L’équipe de chercheurs en conclut que le SARS-CoV-2 peut avoir été transmis par voie aérienne, et qu’il convient de ventiler les pièces, de désinfecter, et de travailler en milieu ouvert le plus possible afin de limiter la propagation du virus.
Une étude similaire a été réalisée dans l’hôpital universitaire du Nebraska, aux États-Unis. Des échantillons d’aérosol et de particules de surface ont été prélevés début mars dans les chambres de treize individus isolés, contaminés par le Covid-19. Dans une pré-publication [6] parue le 26 mars dans la revue medRχiν, les scientifiques à l’origine de ces prélèvements expliquent que 63,2 % des échantillons d’aérosol ont été testés positifs à l’ARN du SARS-CoV-2 – preuve, écrivent-ils, d’une « contamination virale dans l’air ».
À la lecture de ces travaux, deux inconnues majeures perdurent : le nombre d’entités de SARS-Cov-2 et la durée d’exposition nécessaires pour causer une infection chez l’être humain. Mais une certitude semble communément partagée, si l’on en croit la chercheuse Lidia Morawska, de l’université de technologie de Queensland, en Australie : « Dans l’esprit des scientifiques travaillant là-dessus, il n’y a absolument aucun doute que le virus se propage dans l’air », disait-elle début avril à la revue Nature dans un article [7] posant les bases de cette question scientifique.
[1] ▻https://www.medrxiv.org/content/10.1101/2020.04.15.20065995v2
[2] ▻https://www.actris.fr/propagationdusars-cov-2etparticulesatmospheriques
[3] ▻https://www.nejm.org/doi/10.1056/NEJMc2004973
[4] ▻https://www.biorxiv.org/content/10.1101/2020.03.08.982637v1
[5] ►https://www.nature.com/articles/s41586-020-2271-3
[6] ▻https://www.medrxiv.org/content/10.1101/2020.03.23.20039446v2
[7] ▻https://www.nature.com/articles/d41586-020-00974-w
Don’t Wear a Mask for Yourself - The Atlantic
►https://www.theatlantic.com/health/archive/2020/04/dont-wear-mask-yourself/610336
If you feel confused about whether people should wear masks and why and what kind, you’re not alone. COVID-19 is a novel disease and we’re learning new things about it every day. However, much of the confusion around masks stems from the conflation of two very different functions of masks.
Masks can be worn to protect the wearer from getting infected or masks can be worn to protect others from being infected by the wearer. Protecting the wearer is difficult: It requires medical-grade respirator masks, a proper fit, and careful putting on and taking off. But masks can also be worn to prevent transmission to others, and this is their most important use for society. If we lower the likelihood of one person’s infecting another, the impact is exponential, so even a small reduction in those odds results in a huge decrease in deaths. Luckily, blocking transmission outward at the source is much easier. It can be accomplished with something as simple as a cloth mask.
The good news is that preventing transmission to others through egress is relatively easy. It’s like stopping gushing water from a hose right at the source, by turning off the faucet, compared with the difficulty of trying to catch all the drops of water after we’ve pointed the hose up and they’ve flown everywhere. Research shows that even a cotton mask dramatically reduces the number of virus particles emitted from our mouths—by as much as 99 percent. This reduction provides two huge benefits. Fewer virus particles mean that people have a better chance of avoiding infection, and if they are infected, the lower viral-exposure load may give them a better chance of contracting only a mild illness.
COVID-19 has been hard to control partly because people can infect others before they themselves display any symptoms—and even if they never develop any illness. Three recent studies show that nearly half of patients are infected by people who aren’t coughing or sneezing yet. Many people have no awareness of the risk they pose to others, because they don’t feel sick themselves, and many may never become overtly ill.
Models show that if 80 percent of people wear masks that are 60 percent effective, easily achievable with cloth, we can get to an effective R0 of less than one. That’s enough to halt the spread of the disease. Many countries already have more than 80 percent of their population wearing masks in public, including Hong Kong, where most stores deny entry to unmasked customers, and the more than 30 countries that legally require masks in public spaces, such as Israel, Singapore, and the Czech Republic. Mask use in combination with physical distancing is even more powerful.
We know a vaccine may take years, and in the meantime, we will need to find ways to make our societies function as safely as possible. Our governments can and should do much—make tests widely available, fund research, ensure medical workers have everything they need. But ordinary people are not helpless; in fact, we have more power than we realize. Along with keeping our distance whenever possible and maintaining good hygiene, all of us wearing just a cloth mask could help stop this pandemic in its tracks.
This reduction provides two huge benefits. Fewer virus particles mean that people have a better chance of avoiding infection, and if they are infected, the lower viral-exposure load may give them a better chance of contracting only a mild illness.
C’est la réponse à la question que je posais, @monolecte : si on est contaminé par une plus faible charge virale, on s’en sort mieux et plus vite et on s’immunise.
Liens vers
▻https://www.preprints.org/manuscript/202004.0203/v1
▻https://www.nejm.org/doi/full/10.1056/NEJMc2007800
▻https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30196-1/fulltext
►https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30232-2/fulltext
▻https://nymag.com/intelligencer/2020/03/is-viral-load-key-to-understanding-coronaviruss-severity.html
Ageist “Triage” Is a Crime Against Humanity
My cohort of over-65 people are supposed to be enjoying the new Age of Longevity. But do some younger people still associate us older folks with dying — however unconsciously — so that our premature demise may come to seem — sadly — normal? These questions arise with more gravity because the pandemic Covid-19 may become an atrocity-producing situation for older persons. Will anxiety, which already runs high, come to be focused on the figure of an old person who is seen as expendable? This depends on how panicked different nation-states become, and how discourse about victims is structured by governments and the media.
The ethical position is that old people have equal claims to life with anyone else. Arthur L. Caplan, head of the Division of Medical Ethics at NYU’s School of Medicine, writes, “It seems to me that we want to guide our decisions about access to healthcare not by biases about being too old or treatments being too expensive, but first and foremost, we want to ask whether there is benefit. Does it work? Is it going to help the individual?” The ethical responsibility is clear: If a 90-year-old can benefit and wants to have a necessary treatment, give it to her. Risks to older people arise in societies when health care systems are overwhelmed. Given the government delays, this is likely to happen in the United States now: “What will happen when there are 100, or a 1000 people who need the hospital and only a few ICU places are left?” Matthew K. Wynia and John L. Hick, who helped write the Guidelines for Establishing Crisis Standards of Care, give the standard answer, “The ethical justification for withholding or removing potentially lifesaving care from one person or group without their consent and giving it to another is that the latter person or group has a significantly better chance at long-term survival.”
General guidelines become questionable, however, if younger people in power are already implicitly biased, thinking that people much older than they are close to death, or that they have had “full lives,” or that they no longer care to survive. Do you believe this? Doctors may not recognize the ageist prejudice involved in any of these prejudgments. Or they may admit these beliefs, assuming — because ageism is so common — that everyone agrees. An otherwise healthy 75-old gets pneumonia, as does a 37-year-old with end-stage lung cancer. “Which very sick patient gets intensive care?” If the 37-year-old would die even on a respirator … you save the “old man” who could have 25 good years.
In Italy and Switzerland, where the epidemic has stressed the medical system, doctors asking this question are sometimes answering, it seems, on the basis of age alone. In Switzerland, the head of an infectious disease unit, Pietro Vernazza, projects that they will have to weigh “a patient of a certain age in desperate conditions” against “a younger sick person.” But verbally, this is already wrongly decided, by labelling the older person’s condition “desperate” while the younger person is only “sick.” The mayor of Bergamo said that in some cases in Lombardy the gap between resources and the enormous influx of patients “forced the doctors to decide not to intubate some very old patients,” essentially leaving them to die. “Were there more intensive care units,” he added, “it would have been possible to save more lives.”
In a crisis like this, ethical decision-making going case by case must fight every societal bias of long standing: refusing to weigh the life of a white person as worth more than that of a person of color, the life of a man more than a woman, a cis person over a trans person, or a younger person over an older person. And what of an old black woman, or someone else whose intersectional category may activate prejudice? Ethical triage focuses on the individual’s condition, not the sociological category. Training for doctors must include not only clinical guidance, but situational awareness about potential bias.
This ethical trial of rapid decision-making (who will be allowed to survive?) is often foisted on front-line medical personnel who do not have such training. After the Covid-19 epidemic is over, do we want to be forced to conclude that elders died more frequently than younger people (as some early mortality statistics show they do) because, in many cases, age-bias denied them treatment?
Denying anyone medical care is heartbreaking, but denying someone out of bias is exponentially worse. Once aware of the high stakes of medical ageism, some responsible people, particularly as they grow older, may find themselves left with a lifetime of shame and growing remorse.
The advice from the European Society of Intensive Care Medicine’s Task Force on avoiding the tragedies of triage is obvious: “Hospitals should increase their ICU beds to the maximal extent by expanding ICU capacity and expanding ICUs into other areas. Hospitals should have appropriate beds and monitors for these expansion areas.” The real crime at the governmental levels, and at the level of hospital administration, is to not open enough hospital beds and intensive care units, fast enough. Preparation is the task of yesterday, and certainly today. We must do everything we can to avoid hastening the deaths of the old.
As a society, we will be grieving all deaths. Triage is tragic in itself, whether on the battlefield or in civilian hospitals. But only bias makes it criminal. In this saddened state, we should be able to go forward without the added burden of fearing that our country, and our medical personnel, were guilty of a crime against humanity.
▻https://lareviewofbooks.org/short-takes/ageist-triage-covid-19
#tri #crime_contre_l'humanité #âge #coronavirus #covid-19 #vieux #âgisme
Avoiding Ageist Bias and Tragedy in #Triage. Even a lottery is fairer than triage by age
Triage means exclusion from treatment. In parts of the US, triage may become grievously necessary, as pandemic peaks overwhelm resources. Setting proper criteria for such decision-making is crucial for avoiding injustice, guilt, and tragedy. Sorrowfully, a medical consensus on whom to exclude has been forming, in “guidelines” from universities and state commissions, that often works explicitly against the old, and implicitly against people with disabilities, people of color, poor people, and those who live in crowded nursing homes, who are over 75, or 60, or even over 40. Bias in triage decisions is a danger to those whom society has made vulnerable.
“The transition from conventional to , , , crisis care comes with a concomitant increase in morbidity and mortality,” warns a document on “crisis standards of care” transmitted to the Trump Task Force on March 28. [i] This essay responds to recent arguments justifying crisis exclusions that are erroneous and, to my mind, unethical, but, because they are authoritatively presented or widely held, dangerous.
“One thing everyone agrees on is that the most morally defensible way to decide would be to ask the patients,” Dr. Wynia, a bioethicist, is quoted as saying in a survey of opinions reported by Sheri Fink for the New York Times. [ii] This sounds plausible: In health, some people make living wills requesting that if unable to speak for themselves (because of e.g., severe cognitive impairment, coma), they be kept alive with “heroic” measures, or not. Consent is indeed necessary from Covid-19 patients who can speak for themselves, who are gasping and scared and might benefit from ICU or intubation if offered. Would such patients sign the same advance directive now? This is supposed to be a moment of choice, involving reassuring explanations from medical personnel about options (even induced coma).[iii] A danger emerges: some candidates for scarce resources might eliminate (“sacrifice”) themselves.
Consider that internalization of inferiority is real and affects wide swaths of the population. As the feminist and disability rights movements have taught, many people feel they must be self-abnegating: Others’ lives are worth more than theirs, Depressed people may agree to relinquish their chance—but many older people are depressed by the pandemic. We are told often that our lives are more at risk than the lives of others. Family members will be unavailable if we are hospitalized. And, because we are suddenly framed as less valuable by popular opinion and some medical guidelines, older and disabled people may feel expendable.
The elderly and disabled category has had pointed aggressive societal pressure aimed at them for a long time. Vehemently denied but still widely held, is the feeling that the older the patient, the more undeserving of treatment. “So close to death already.” The attitude spreads, first unconsciously and now explicitly, that younger adults are more valuable than older adults; the healthy more desirable than the less abled.
Ageism permeating the medical profession, a widespread problem, adds to triage confusion. Older people–not deaf and not cognitively impaired—complain in conventional situations that their doctors often ignore them, preferring to talk to their adult children. We are not seen. We may insultingly be considered “burdens”–too costly, too unproductive, too time-consuming.
Equal treatment, a constitutional right and an existential necessity, is likely to be ignored in the crisis situation. The University of Pittsburgh guidelines, a model, don’t mince words. The tie-breaker should be age. (A tie means all patients with that score have an equal likelihood of survival.) These guidelines give priority to younger patients within these age groups: 12 to 40, 41 to 60, 61 to 75, over 75+. (Massachusetts’ new guidelines are similar, as reported on April 13th.) The Pittsburgh document calls this “the life-cycle principle.” [iv] A principle! That sounds not just plausible but lofty. Less so if we call it “culling the old.” The United States has seen a growth of longevity that any nation could be proud of. Now their longevity may be used against people as young as forty.
Do the math. If age is the tie-breaker, let’s say there are 10 ventilators, and 100 people who are tied in terms of equal benefit. One is 83 years old, 4 are 70; 22 are 60, 35 are 50; the rest are under 40. All 10 of those under 40 would get the ventilators; none of the others. That is culling the old. Some triage guidelines suggest patients be warned their ventilator could be taken away from them. Some triage guidelines suggest patients be warned their ventilator could be taken away from them.[v] Isn’t a lottery more fair? A lottery system (for a brief time of crisis) may horrify some people, but in the long run “the ice floe” principle is far more perilous for a society.
With hostile ageism rampant, as we see, mere chronology counts more than an individual’s medical condition. An article in NEJM gives “priority to those who are worst off in the sense of being at risk of dying young and not having a full life.” [vi] The retired veteran New York philosopher, Andrew Wengraf, argues against the “full-life” argument.
Age may be a vivid sociological category, but to age is just to go on living. It is true that when Bertrand Russell died age 97 he was said to have had a fulfilled life, a life not free of disappointments but certainly fulfilled. . . . And inasmuch as life is finite, we are nearer death when we are old. But Russell was not obliged to die because of having enjoyed a long, rich life. The burden of proof is on anyone who thinks Russell has a duty to die prematurely. That person needs to explain how Russell could acquire that discriminatory outcome as an obligation. Without that, it cannot simply be imposed upon him in a triage queue.
New York state’s guidelines are not ageist; Governor Andrew Cuomo said categorically, “My mother is not expendable.” Justice in Aging, a San Francisco legal NGO that protects low-income older people, has co-written a letter to California health officials asking that treatment discussions “include an explicit prohibition on triage and triage guidance that consider an individual’s estimated remaining number of years of life and other factors that cannot realistically be operationalized without taking age into account.”[vii] The Johns Hopkins criteria for treatment, which rightly depended on public input, ask no more than one year of potential life, thus respecting people in their nineties. I have a dear aunt who is 99, healthy, practicing social isolation, not ready to die. At 79, I assert that my life is worth no more than that of my aunt, nor less than that of a 30-year-old.
Ethicists rightly omit most exclusion criteria (color, gender, low income). Future perceived value ought to be another no-no. Behind the mask, fortunately, a doctor cannot tell if that person with double pneumonia is Einstein or a homeless person of the same age. But age is as visible as gender and race. If we were to exclude people because of age, we would lose many of our current leaders. The UK would lose Queen Elizabeth. And some disabilities are clearly visible.
In a hospital crisis, ethical decision-making going case by case must fight every societal bias of long standing: refusing to weigh the life of a white person as worth more than that of a person of color, the life of a man more than a woman, a cis person over a trans person, an apparently able person over a person with an obvious disability, or a younger person over an older person. And what of an old black woman, or someone else whose visible intersectional category may activate prejudice? Ethical triage even in crisis care should focus on the individual’s medical condition, not the sociological category. Training for doctors and nurses must include not only clinical guidance, but situational awareness about potential bias.
Having to decide on triage occurs at many stages, from EMTs to the bedside. Excluding people or withdrawing treatment from some may feel tragic to doctors, as well as for the patients who die, and for their families. Where bias rules, however, triage becomes criminal. The government document to the Trump Task Force, wants all healthcare workers to have “adequate guidance and legal protections . . . from unwarranted liability” (p.4).
But even the best-designed bias training cannot prevent the appearance at these multiple decision points of many people suffering from long-term health inequalities based on gender, race, national origin, or immigrant status, and low income. For them discrimination starts in utero, with inadequate prenatal care. Early deficiencies may grow worse (toxic environments, substandard housing) throughout life, as sociologist Dale Dannefer has shown through his concept of cumulative disadvantage. [viii] Middle ageism—causing people to lose jobs early in life, preventing them from finding work again—leads to family dysfunction, foreclosure, diseases of stress. Inequality goes on so relentlessly that such people are inevitably at more risk if Covid-19 hits them. Injustice is clearly built into any crisis standard of care that prioritizes the likelihood of highest long-term survival, in a society that has lacked Medicare for All for the past sixty years.
The most just answer seems to be that all those with similar conditions and equal chances of one-year survival, participate in a lottery. A petition to this effect, addressed to the US Surgeon General, called “Just Rationing,” can be signed at Change.org/JustRationing
The US government, burdened with racist, market-driven, small-government ideology, for decades denied the poor the right to health care and exacerbated inequality. Under Trump the government underfunded its public health service, disregarded science, procrastinated in preparations. The underfunding of nursing homes, the overwork and underpayment of staff, have already led to uncountable deaths. In many countries, the excess deaths of the pandemic will be the fault of the state. The deaths incurred thereby are crimes against humanity.
But suppose the curve flattens–we are spared triage! Eventually the data will tell us how many died after having suffered a life of disadvantages. What has been revealed already, however, through these calm, ostensibly reasonable, “ethical” medical guidelines, is a frightening explosion of explicit hate speech against people who are simply older. Older than the valued young. An entire nation has learned that this is normal and expectable. When pinch comes to shove, we alone have a duty to die, cursed by our date of birth. In the midst of grief, outrage.
——————————————————-
[i] National Academies of Sciences, Engineering, and Medicine. 2020. Rapid Expert Consultation on Crisis Standards of Care for the COVID-19 Pandemic (March 28, 2020). Washington, DC: The National Academies Press, p. 3.. ▻https://doi.org/10.17226/25765. ▻https://www.nap.edu/catalog/25765/rapid-expert-consultation-on-crisis-standards-of-care-for-the-covid-19-pandemic
[ii] Sheri Fink, “The Hardest Questions Doctors May Face: Who Will Be Saved? Who Won’t?
▻https://www.nytimes.com/2020/03/21/us/coronavirus-medical-rationing.html
[iii] See for example, the interview with a respiratory therapist at Newton-Wellesley Hospital, Boston Globe, April 15, 2020: p. .
[iv] U of Pittsburgh, Department of Critical Care Medicine, “Allocation of Scarce Critical Care Resources During a Public Health Emergency Executive Summary,” p. 6, 8. ▻https://ccm.pitt.edu/sites/default/files/UnivPittsburgh_ModelHospitalResourcePolicy.pdf
[v] “Fair Allocation of Scarce Medical Resources in the Time of Covid-19,” by Ezekiel J. Emanuel et al, NEJM March 23, 2020. ►https://www.nejm.org/doi/full/10.1056/NEJMsb2005114?query=RP
[vi] “Fair Allocation of Scarce Medical Resources in the Time of Covid-19,” by Ezekiel J. Emanuel et al, NEJM March 23, 2020. ►https://www.nejm.org/doi/full/10.1056/NEJMsb2005114?query=RP Dr. Emanuel is the author of the notorious article in The Atlantic that said all people should voluntarily refuse medical care after age 75, and that he would do so.
[vii] Included in a bulletin from Justice in Aging, “Justice in Aging Statement on Discriminatory Denial of Care to Older Adults,” April 4, 2020. ▻https://www.justiceinaging.org/wp-content/uploads/2020/04/Justice-in-Aging-Letter-to-Sec-Ghaly-Age-Discrimination-04032020.pdf
[viii] Dale Dannefer, “Cumulative Advantage/Disadvantage and the Life Course: Cross-Fertilizing Age and Social Science Theory,” Journal of Gerontology: Social Sciences Vol 58b (2003).
Compassionate Use of #Remdesivir for Patients with Severe Covid-19 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2007016
In this cohort of patients hospitalized for severe Covid-19 who were treated with compassionate-use remdesivir, clinical improvement was observed in 36 of 53 patients (68%). Measurement of efficacy will require ongoing randomized, placebo-controlled trials of remdesivir therapy. (Funded by Gilead Sciences.)
Ten Weeks to Crush the Curve | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMe2007263?query=featured_home
The President says we are at war with the #coronavirus. It’s a war we should fight to win.
The economy is in the tank, and anywhere from thousands to more than a million American lives are in jeopardy. Most analyses of options and trade-offs assume that both the pandemic and the economic setback must play out over a period of many months for the pandemic and even longer for economic recovery. However, as the economists would say, there is a dominant option, one that simultaneously limits fatalities and gets the economy cranking again in a sustainable way.
#contagiosité et évolution des cas #asymptomatiques et #pré-symptomatiques.
(Fil complémentaire : Proportion de personnes SARS-Cov2 positives asymptomatiques. ▻https://seenthis.net/messages/844464)
#COVID-19 #Transmission within a family cluster by presymptomatic infectors in China
▻https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa316/5810900
Étude concernant un foyer de 9 membres dont 8 ont été contaminés par deux sujets asymptomatiques venus leur rendre visite en même temps (dont l’un est devenu symptomatique par la suite et l’autre pas).
Le cas non contaminé est un enfant de 6 ans (4 PCR à la suite, dont 3 sur prélèvement au niveau de la gorge et 1 au niveau rectal).
Asymptomatic people without coronavirus symptoms might be driving the spread more than we realized - CNN
►https://www.cnn.com/2020/03/14/health/coronavirus-asymptomatic-spread/index.html
#Coronavirus : au moins une contamination sur deux due à une personne sans symptômes
►http://www.allodocteurs.fr/maladies/maladies-infectieuses-et-tropicales/coronavirus/coronavirus-au-moins-une-contamination-sur-deux-due-a-une-personne-sans
Questions and answers regarding laboratory topics on SARS-CoV-2
▻https://seenthis.net/messages/837594
Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled…
▻https://seenthis.net/messages/838433
Temporal dynamics in viral shedding and transmissibility of COVID-19 | Nature Medicine
►https://seenthis.net/messages/843843
44% des cas « secondaires » seraient contaminés durant la phase pré-symptomatique des cas index.
Covid-19 : les patients asymptomatiques seraient aussi contagieux que les autres | Le Quotidien du…
▻https://seenthis.net/messages/843053
Asymptomatic #Transmission, the Achilles’ Heel of Current Strategies to Control #Covid-19 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMe2009758
Contact Tracing Assessment of COVID-19 Transmission Dynamics in Taiwan and Risk at Different…
▻►https://seenthis.net/messages/850588
Dans cette étude un sujet asymptomatique (et qui l’est resté par opposition au cas pré-symptomatique) (9 cas) n’a jamais été contagieux.
Position Statement from the National Centre for Infectious Diseases and the Chapter of Infectious…
►https://seenthis.net/messages/855917
Ce compte-rendu de l’expérience singapourienne sur la période de #contagiosité du #sars_cov2 rapporte une étude locale [Wei WE, Li Z, Chiew CJ, et al. Pre-symptomatic transmission of SARS-CoV-2 - Singapore, January 23 - March 16, 2020. MMWR Morb Mortal Wkly Rep. 2020 ; 69 : 411- 41] où il n’a pas été retrouvé de transmission par des sujets asymptomatiques (à la différence des pré-symptomatiques).
OMS 5 juin 2020 (page 2) : dans l’état actuel des connaissances les sujets qui restent asymptomatiques sont beaucoup moins contagieux que les pré-symptomatiques (les plus contagieux étant les symptomatiques)
►https://seenthis.net/messages/859503
Comprehensive studies on transmission from asymptomatic individuals are difficult to conduct, but the available evidence from contact tracing reported by Member States suggests that asymptomatically-infected individuals are much less likely to transmit the virus than those who develop symptoms.
Natural history and transmission potential of asymptomatic SARS-CoV-2 infection | Clinical…
►https://seenthis.net/messages/859749
Parmi 13 cas asymptomatiques, 2 auraient « probablement » contaminé des sujets contacts.
Ce qui est certain c’est que une des principales difficultés de la limitation de la propagation du sars-cov2 est la possibilité pour le malade de le transmettre à des contacts dans les 2-3 jours avant l’apparition des symptômes (derniers jours de la période d’incubation ou phase pré-symptomatique).
Early Release - Clusters of Coronavirus Disease in Communities, Japan, January–April 2020 - Volume…
▻https://seenthis.net/messages/860925
41% (9/22) of probable primary case-patients were presymptomatic or asymptomatic at the time of #transmission.
Résultats comparables à : ►https://seenthis.net/messages/843843
Part des formes asymptomatiques et transmission du SARS-CoV-2 en phase pré-symptomatique. Synthèse…
►https://seenthis.net/messages/867359
environ 50% des transmissions surviennent durant la phase pré-symptomatique du patient source. Nous n’avons pas trouvé d’élément pour caractériser le potentiel de transmission des formes complètement silencieuses de l’infection.
COVID-19 : Asymptomatique, une personne en contamine 71 autres en prenant un ascenseur - Marie…
▻https://seenthis.net/messages/867595
What the data say about asymptomatic COVID infections
▻https://seenthis.net/messages/887548
Transmission Dynamics of COVID-19 Outbreaks Associated with Child Care Facilities — Salt Lake City,…
►https://seenthis.net/messages/875654
Parmi 3 enfants asymptomatiques 2 ont contaminé leur entourage.
Twelve children acquired COVID-19 in child care facilities. Transmission was documented from these children to at least 12 (26%) of 46 nonfacility contacts (confirmed or probable cases). One parent was hospitalized. Transmission was observed from two of three children with confirmed, asymptomatic COVID-19.
Post-lockdown SARS-CoV-2 nucleic acid screening in nearly ten million residents of Wuhan, China
▻https://seenthis.net/messages/889850
SARS-CoV-2 Transmission From People Without COVID-19 Symptoms | Infectious Diseases | JAMA Network…
▻https://seenthis.net/messages/895030
59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms.
Early Release - Analysis of Asymptomatic and Presymptomatic Transmission in SARS-CoV-2 Outbreak,…
▻https://seenthis.net/messages/904050
Contagiosité des cas source par ordre décroissant : pré-symptomatiques (75%), symptomatiques, asymptomatiques (0%).
SARS-CoV-2 transmission without symptoms | Science
▻https://seenthis.net/messages/907705
COVID-19 : Le cas le plus long était asymptomatique | santé log
▻https://seenthis.net/messages/932405
Florian Zores sur Touiteur :
▻https://twitter.com/FZores/status/1243459929618423808
Un peu d’histoire de la médecine (on va parler de cardiologique évidement) #fil
Au tournant des années 1980, la communauté cardiologique s’est rendue compte qu’après un infarctus, les patients qui faisaient des extrasystoles ventriculaires avaient plus de risque de mourir
Qu’est-ce qu’une extrasystole ventriculaire (ESV) : c’est une anomalie du rythme cardiaque pouvant entrainer des troubles du rythme graves voire mortels.
▻https://t.co/P1qo3Ffa40?amp=1
Et les ESV sont notamment favorisées par l’ischémie myocardique, c’est à dire le défaut d’apport en oxygène au muscle cardiaque en raison d’une maladie des artères nourrissant le coeur (les artères coronaires)
Donc le tableau était cohérent :
infarctus -> ischémie
ischémie -> ESV
ESV -> décès
donc
ESV après infarctus -> décès
C’est ce que montraient plusieurs études observationnelles
▻https://pbs.twimg.com/media/EUGjIuZWkAArsRj?format=png&name=medium
les références :
▻https://www.nejm.org/doi/full/10.1056/NEJM197710062971404
▻https://www.ahajournals.org/doi/pdf/10.1161/01.CIR.69.2.250
Je rappelle qu’une étude observationnelle permet de suggérer une corrélation, pas une causalité
En d’autres termes, on savait que l’augmentation du nombre et de la complexité des ESV était ASSOCIÉE à une augmentation de la mortalité, mais pas qu’elle CAUSAIT le décès
Pour savoir s’il y a causalité, il faut voir si en supprimant la cause (les ESV) on diminue la fréquence de la conséquence (les décès).
On fait pour cela un essai randomisé contre un traitement de référence, ou contre rien s’il n’y a pas de traitement de référence
Donc on a fait l’étude CAST.
▻https://www.nejm.org/doi/full/10.1056/NEJM199103213241201
On a pris 1400 patients.
La moitié a reçu un traitement antiarythmique dont on sait qu’il diminue le nombre des ESV.
La moitié a reçu un placébo.
Il n’y a pas de problème éthique : on ne sait pas si le traitement fonctionne, et au moment de l’étude il n’y a pas de traitement de référence des ESV post-infarctus
(Personne n’a hurlé au fait qu’il y avait une perte de chance pour les patients sous placebo)
Surtout que ...
Les résultats de l’étude ont totalement bouleversé le monde médical et cardiologique
car...
ce sont les patients sous traitement anti-arythmique qui meurent le plus !
Et en plus ils meurent plus... par trouble du rythme
▻https://pbs.twimg.com/media/EUGlN6RXQAY3Hbt?format=png&name=large
▻https://pbs.twimg.com/media/EUGl9MGXkAEstiY?format=png&name=medium
On venait donc de démontrer que le médicament censé sauver les patients en diminuant les troubles du rythme, tuait les patients en provoquant des troubles du rythme.
Ce qui favorise le décès ce ne sont pas les ESV, mais ce qui cause les ESV.
En d’autre terme, les ESV ne sont qu’un marqueur du risque de décès.
Ce le traitement de ce qui cause les ESV qui permettra de baisser la mortalité.
Mais c’est une autre histoire
Voilà pourquoi
> On ne fait pas de médecine sur des « il semble » et sur des études observationnelles qui donnent des corrélations
> il faut rechercher la preuve de l’efficacité et la confirmation du lien de causalité par un essai randomisé
et surtout, le groupe placébo n’est pas forcement celui qui n’a pas de chance au tirage. Tant qu’un essai n’a pas été fait, on ne peut être sûr que le médicament ne soit pas plus dangereux que rien
#fin
Merci pour votre travail. Et en particulier dans ce message, votre pédagogie pour dissocier une corrélation d’avec une relation de cause à effet. Dans notre culture générale, ceci est loin d’être acquis, d’où une prise offerte à toutes les désinformations.
Rien à voir mais c’est malheureux d’en être réduit à utiliser de tels outils comme Twitter, aussi mal conçus (pour ça, en tout cas) juste parce qu’il y a probablement plus d’audience (ou pas ? Je vois que certains blogs ont toujours un certain succès). Le nombre de fils en ce moment sur 10 messages ou plus, hyper instructifs, mais rendus tellement pénibles à lire...
Ici, on peut les compiler efficacement.
Fair Allocation of Scarce Medical Resources in the Time of Covid-19 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMsb2005114
These ethical values — maximizing benefits, treating equally, promoting and rewarding instrumental value, and giving priority to the worst off — yield six specific recommendations for allocating medical resources in the Covid-19 pandemic: maximize benefits; prioritize health workers; do not allocate on a first-come, first-served basis; be responsive to evidence; recognize research participation; and apply the same principles to all Covid-19 and non–Covid-19 patients.
#soin
Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1 | NEJM
►https://www.nejm.org/doi/full/10.1056/NEJMc2004973
SARS-CoV-2 was more stable on plastic and stainless steel than on copper and cardboard, and viable virus was detected up to 72 hours after application to these surfaces
Résumé : c’est une bestiole très collante : après 3 jours on en trouve encore des traces sur du plastique, de l’acier, du cuivre et du carton. (L’article n’indique pas au bout de combien de temps ce n’est plus contagieux, ne lui faites pas dire ce qu’il ne dit pas.)
#charge_virale et durée de viabilité du sars-cov2
#Contagiosité des patients porteurs du sars-cov2
Les super-spreaders du #coronavirus : que faut-il savoir ? - BBC News Afrique
▻https://www.bbc.com/afrique/monde-51452139
Qu’est-ce qu’un super-propagateur ?
Baptisé « super-spreader » en anglais, ce terme vague, sans réelle définition scientifique, décrit une personne porteur du virus qui en contamine accidentellement plusieurs autres.
En moyenne, chaque personne contaminée par le coronavirus le transmet à deux ou trois autres personnes.
Mais ce n’est qu’une moyenne ; certaines personnes ne le transmettront à personne tandis que d’autres contamineront bien plus de personnes.
Infected people without symptoms might be driving the spread of coronavirus more than we realized - CNN
►https://www.cnn.com/2020/03/14/health/coronavirus-asymptomatic-spread/index.html
On Tuesday, Dr. Sandra Ciesek, director of the Institute of Medical Virology in Frankfurt, Germany, tested 24 passengers who had just flown in from Israel.
Seven of the 24 passengers tested positive for coronavirus. Four of those had no symptoms, and Ciesek was surprised to find that the viral load of the specimens from the asymptomatic patients was higher than the viral load of the specimens from the three patients who did have symptoms.
Viral load is a measure of the concentration of the virus in someone’s respiratory secretions. A higher load means that someone is more likely to spread the infection to other people.
Il est a priori contre-intuitif de retrouver une charge virale forte chez des sujets asymptomatiques (donc a priori avec une forte immunité) (?)
Une compilation sur ce sujet :
►https://seenthis.net/messages/842370
En français, c’est très classiquement ce qu’on appelle un porteur sain.
Ce n’est pas du tout le sujet. La question que je soulève est qu’il est a priori contre-intuitif qu’un porteur sain soit porteur d’une charge virale bien plus forte que la moyenne.
OK, merci. J’en étais plus resté à la lecture des articles qu’à ton commentaire, et les articles (notamment celui de CNN) développement assez longuement le principe de porteur qui n’a pas de symptômes mais transmet le virus (ce qui, pour le coup, ne me semblait pas du tout inhabituel).
Ceci dit les cas asymptomatiques peuvent être non pas des porteurs sains mais en période d’incubation (pré-symptomatiques).
Coronavirus : au moins une contamination sur deux due à une personne sans symptômes
►https://www.allodocteurs.fr/maladies/maladies-infectieuses-et-tropicales/coronavirus/coronavirus-au-moins-une-contamination-sur-deux-due-a-une-personne-sans
Or, pour combattre l’épidémie, une partie des mesures consiste à rechercher les cas et à identifier leurs contacts malades. « Cela signifie que l’efficacité [de ces mesures] dans la prévention des infections Covid-19 sera considérablement plus faible que l’efficacité de la prévention du SRAS ou des infections MERS (deux virus de la même famille que le Covid-19, ndlr), où la transmission pré-symptomatique ne jouait pas un rôle important » notent les chercheurs dans leur étude.
Ici un patient qui a contaminé deux personnes pendant sa phase pré-symptomatique (non testé à ce moment là), et qui avait un PCR fortement positif alors qu’il n’avait plus de symptômes. Les auteurs posent la question de savoir s’il s’agit de virus encore viables. Dans le cas contraire on pourrait théoriquement avoir un PCR (éventuellement fortement) positif sans être contagieux.
Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMc2001468
... the detection of 2019-nCoV and a high sputum viral load in a convalescent patient (Patient 1) arouse concern about prolonged shedding of 2019-nCoV after recovery. Yet, the viability of 2019-nCoV detected on qRT-PCR in this patient remains to be proved by means of viral culture.
Dr Siouxsie Wiles sur Twitter : “For everyone hearing that the coronavirus “survives” for 17 days. This is not what the CDC reported. They detected its genetic material after 17 days. They didn’t test whether the virus was viable. For context, you can destroy a virus in an autoclave & still detect it this way.”
▻https://seenthis.net/messages/834126
Understanding COVID-19 : what does viral RNA load really mean ? - The Lancet Infectious Diseases
►https://seenthis.net/messages/835591
Virological assessment of hospitalized patients with COVID-2019 | Nature
▻https://seenthis.net/messages/837496
Does high viral load increase ability to pass the virus to others?
►https://theconversation.com/what-we-do-and-do-not-know-about-covid-19s-infectious-dose-and-vira
In general, the more virus you have in your airways, the more you will release when you exhale or cough, although there is a lot of person-to-person variation. Multiple studies have reported that patients have the highest viral load of the coronavirus at the time they are diagnosed.
This means that patients transmit COVID-19 more effectively at the beginning of their illness, or even before they know they are sick. This is bad news. It means people who look and feel healthy can transmit the virus to others.
Contact Tracing Assessment of COVID-19 Transmission Dynamics in Taiwan and Risk at Different…
►https://seenthis.net/messages/850588
Dans cette étude les sujets symptomatiques ne sont contagieux que quelques jours avant et jusqu’à 5 jours après le début de leurs symptômes, alors même que le PCR reste positif au-delà du cinquième jour. Un sujet asymptomatique (9 cas) n’a jamais été contagieux.
Illustré par Siouxsie Wiles & Toby Morris
▻https://seenthis.net/messages/850588#message850835
Revue succincte de la littérature sur les modes de transmission du sars-cov2 Thread by mugecevik : A…
▻https://seenthis.net/messages/851985
Les écoles vont rouvrir, mais les scientifiques essaient toujours de comprendre comment les enfants…
►https://seenthis.net/messages/851543
Interpreting Diagnostic Tests for SARS-CoV-2 | Infectious Diseases | JAMA | JAMA Network
▻https://seenthis.net/messages/852413#message852496
Cite une étude de 9 cas où aucune culture n’est revenue positive 8 jours après le début des symptômes.
Why do some COVID-19 patients infect many others, whereas most don’t spread the virus at all ? |…
►https://seenthis.net/messages/854393
10% des contaminés seraient responsables de 80% des transmissions.
Position Statement from the National Centre for Infectious Diseases and the Chapter of Infectious…
►https://seenthis.net/messages/855917
Compte-rendu de l’expérience singapourienne sur la période de #contagiosité du #sars_cov2
– Les cultures de sars_cov2 n’ont jamais été positives après le 11ieme jour ou lorsque le cycle de seuil (Ct ; d’autant plus élevé que la charge virale au #PCR est faible) est supérieur ou égal à 30 : les patients pourraient donc être autorisés à sortir de l’hôpital avant la négativité du PCR qui peut prendre plus d’un mois,
– il n’a pas été retrouvé de transmission par des sujets asymptomatiques (à la différence des pré-symptomatiques).
It’s Not Whether You Were Exposed to the Coronavirus. It’s How Much. - The New York Times
▻https://seenthis.net/messages/857394
Generally, people who harbor high levels of pathogens — whether from influenza, H.I.V. or SARS — tend to have more severe symptoms and are more likely to pass on the pathogens to others.
But in the case of the new coronavirus, people who have no symptoms seem to have viral loads — that is, the amount of virus in their bodies — just as high as those who are seriously ill, according to some studies.
Contagiosité improbable après 7 jours de maladie et/ou Ct supérieur ou égal à 24.
▻https://seenthis.net/messages/857780
Natural history and transmission potential of asymptomatic SARS-CoV-2 infection | Clinical…
▻►https://seenthis.net/messages/859749
Nasal swabbing showed that the infected but asymptomatic study participants had lower levels of viral RNA than infected people who felt ill at some point.
How ’Superspreading’ Events Drive Most COVID-19 Spread - Scientific American
►https://seenthis.net/messages/862821
Early Release - Contact Tracing during Coronavirus Disease Outbreak, South Korea, 2020 - Volume 26,…
►https://seenthis.net/messages/867771
Duration of Isolation and Precautions for Adults with COVID-19 | CDC
▻https://seenthis.net/messages/867867
VIDAL - COVID-19 : les mesures_barrières préviennent-elles l’apparition de symptômes en cas d’infection ?
▻https://seenthis.net/messages/869831
Etats-Unis : un seul événement à l’origine de l’épidémie de Covid-19 à travers le pays ? - L’Express
►https://seenthis.net/messages/873197
Covid-19 : la chasse aux super-propagateurs pour réussir le déconfinement - Science & Vie
▻https://seenthis.net/messages/891150
La charge virale naso-pharyngée serait un indicateur de #contagiosité, celle salivaire de sévérité,
Prof. Akiko Iwasaki sur Twitter :
"URT virus is key to transmission, but LRT is key to severe #COVID19. Saliva appears to be better at capturing the critical viral source driving severe disease.
►https://twitter.com/VirusesImmunity/status/1348289351894134785
Viral kinetics of SARS-CoV-2 over the preclinical, clinical, and postclinical period - PubMed
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Catch me if you can : Superspreading of SARS-CoV-2 : Trends in Microbiology
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Oral Desensitization to Peanuts | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMe1813314
The potential market for these products is believed to be billions of dollars. It is perhaps salutary to consider that in the study conducted by the Cambridge group, children underwent desensitization with a bag of peanut flour costing peanuts.
Un traitement contre les #allergies aux #arachides au coin de la rue, mais les coûts sont inquiétants Société – Nouvelles Du Monde
▻https://www.nouvelles-du-monde.com/un-traitement-contre-les-allergies-aux-arachides-au-coin-de-la-r
(Français très approximatif par moments)
Les scientifiques pensent que les enfants devront continuer à consommer des protéines d’arachide pour rester en sécurité, peut-être toute leur vie.
[...]
Le Dr Michael Perkin, consultant honoraire en allergies pédiatriques à l’hôpital St George’s de Londres, explique dans un éditorial du NEJM qu’il est bon de rappeler que le traitement utilisé à Cambridge était « un sac de farine d’arachide coûtant des arachides ».
« Ce n’est pas comme si c’était une sorte de médicament miracle créé avec un anticorps monoclonal dans un laboratoire intelligent. Ils ont exactement la même farine d’arachide et l’ont insérée dans une capsule », a-t-il déclaré au Guardian.
#prix
Mortality in Puerto Rico after Hurricane Maria | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMsa1803972
This household-based survey suggests that the number of excess deaths related to Hurricane Maria in Puerto Rico is more than 70 times the official estimate.