Covid-19: What does the new distinction between “positive” and “weak positive” correspond to in the result of PCR tests?

Question asked on 10/08/2020

Hello,

The analysis of the results of RT-PCR tests that measure the viral load of Sars-CoV-2 in a patient has been the subject of much debate in recent months. These tests make it possible to detect the RNA (molecule close to DNA) of the virus in the patient’s nasopharyngeal sample, thanks to a process of amplification of the genome by cycles. The techniques available make it possible to target between 1 and 3 viral genes. The more cycles it takes to make the RNA noticeable (this value is generally between 10 and 45) the less virus there is in the sample taken. This threshold cycle (CT) from which a result is positive has been at the heart of the debates for several weeks.

In the United States, an article from New York Times published at the end of August cast doubt on the usefulness of these tests practiced all over the world as part of the fight against the Covid-19 epidemic, as we explained in a previous answer. With a value of

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Emma Donada

.

Covid-19: do antibodies disappear over time?

Question asked by Céline on 09/09/2020

Hello,

You ask us whether it is true that former infected people can present a negative serological test. We now know that the vast majority of people infected with Sars-Cov-2 produce specific antibodies against the virus. These antibodies (IgM and IgG) are detectable using serological tests. But let’s point out right away that the minimum amount of neutralizing antibodies necessary to be protected against reinfection is not yet known.

“With serological tests, you test the antibodies produced by the body against the virus, this is adaptive humoral immunity, one of the three components of the immune response. Since this immunity is adaptive, it takes some time. Between five and six days. It is detectable from around the seventh day, but it is recommended to measure it from the fourteenth day to be sure to spot everyone, because the production of antibodies varies enormously from one individual to another ”, explains Cédric Carbonneil, head of the evaluation service for professional acts of the Haute Autorité de santé. He also recalls that, for the time being, the serological test is considered “A diagnostic supplement”, for which the RT-PCR test is preferred. This type of examination should therefore not be carried out too soon after contamination, at the risk of obtaining a false negative.

“Decrease in neutralizers within two to four months”

As for the lifespan of antibodies in the blood, it varies greatly depending on the virus. For measles, for example, neutralizing antibodies (which help fight infection) are produced throughout life after infection or vaccination, compared with a few months for influenza. “From the outset, we had some concerns with the Sars-Cov-2, because with its cousins ​​the Sars-Cov-1 and the Mers, we had immunity from a few months to a few years. Furthermore, coronaviruses and those responsible for rhinitis and winter viral infections do not provide long-term immune protection ”, continues Cédric Carbonneil.

So there was more chance that the amount of antibody would decrease rapidly. However, several studies published since the start of the pandemic only reinforce these fears. “To date, we know that the Sars-Cov-2 infection is capable of inducing the production of neutralizing antibodies in most patients. We are starting to have some controversial elements regarding the potential term of protection. Several studies have shown a decrease in neutralizers two to four months after infection. An article indicates that there is a drop in antibodies after two months. Another more recent indicated that the lifespan of neutralizing antibodies would be two months and disappearance after four months. There was also the case of a re-infected patient. The prevailing global hypothesis is that we would still be producing antibodies in the fairly short term ”, always indicates the head of HAS.

“Reactivated antibody production”

In France, the Institut Pasteur and the Strasbourg University Hospital are studying the evolution of the level of antibodies from former contaminants. A first study of 160 hospital staff was published in July 2020 and another is still ongoing. “In the first study, we knew that from the date of the first symptoms, in a period between twenty and forty days, we still saw a phase of increase. Antibody production corresponds to a bell-shaped curve. We studied the first phase of growth, there we study the second ”, explains Olivier Schwartz, head of the virus and immunity unit at the Institut Pasteur.

According to the preliminary results of the second study, the amount of antibody decreases on average by 50% after three months. “We have observed a drop in anti-Sars-Cov-2 antibodies, or even a complete negativation of the serology. This means that in these people, the antibodies are in very low quantities, and that they become undetectable by certain tests. On the other hand, this does not mean that they are no longer protected, because when they encounter the virus again, the body should reactivate the production of antibodies ”, explains Samira Fafi-Kremer, director of the Strasbourg Institute of Virology. A negative serological test would therefore not necessarily mean that the person is no longer protected.

“Antibodies are produced by cells [les lymphocytes B et T, ndlr] which can activate or reactivate and “produce” again in the event of another encounter with the virus, but this remains for a limited time. And this is the concern: from an antibody response towards one microbe to that towards another microbe, the durations of this memory vary enormously ”, summarizes Frédéric Altare, immunologist and research director at the National Institute of Health (Inserm). This is called cellular immunity. Another aspect of the immune response whose effectiveness against Sars-Cov-2, still unknown, and which does not appear in the serological tests currently carried out.


Emma Donada

.

Covid-19: what do we know today about the transmission of the virus by aerosols in confined spaces?

Question asked by BARALE on 08/22/2020

Hello,

The start of the school year is masked, In the enterprises as in classrooms. Before these decisions were made, one could read, in Libé on August 14, a forum of a collective of “health professionals” (“Covid-19: the risk exists in all enclosed places, in classrooms as well as in offices”) : “We affirm it without ambiguity: Sars-CoV-2 is transmitted through the air and does not make the mask compulsory in classrooms or amphitheatres, in open spaces, meeting rooms, workshops and shared offices does not comply with science and WHO data. ”

In the light of these very affirmative lines, you ask us about the state of science about the transmission of the virus in the air. There is in fact no consensus on the circulation of Covid-19, from one individual to another in the general population, via “aerosols”, these microdroplets which remain in suspension and which could be vectors of active virus. and infectious.

Two doctors, authors of the forum, recognize from CheckNews that the wording “without ambiguity: Sars-CoV-2 is transmitted through the air ” is not ideal. But that it responds to a precautionary principle: there is a risk that airborne transmission exists, including outside hospitals or laboratories (where it has been documented).

You also asked us Is wearing a mask outside useful?

Warning from scientists

At the beginning of july, 239 scientists from 30 countries warn about the aerosol distribution of the virus. Addressing international health institutions (including the WHO) and national, they recommend great vigilance regarding the transmission of the virus by microdroplets: “Of course, aerosol transmission of Sars-CoV-2 is not yet universally recognized; but, according to our collective assessment, there is sufficient evidence that the precautionary principle should apply. In order to control the pandemic, while waiting for the possibility of vaccination, all transmission routes must be cut off. ”

Several articles or forums have been devoted to the impact of this publication on the authorities (in French, in English). In France, the Director General of Health, Jérôme Salomon, approached the High Council for Public Health. The HCSP had already expressed itself on the subject in a notice published on April 8 (and to a lesser extent in a notice published on April 24).

In this April text, we read in particular: “Aerosol transmission is biologically plausible when (1) infectious aerosols are generated by or from an infectious person, (2) the pathogen remains viable in the environment for a period of time, and (3) tissues targets in which the pathogen initiates infection are accessible by aerosol. […] For Sars-CoV, the level of evidence for aerosol transmission indicates that the evidence for conditions 1 and 3 is moderate and strong for condition 2. “

CheckNews also made a point on the state of science regarding aerosolization at the beginning of April. In an article published in May on the circulation (or not) of the new coronavirus in air conditioning, we also wrote: “Although it is possible for smaller virus particles to remain suspended in the air (this is called an aerosol), an infection requires that a sufficiently large number of active copies of the virus enter the body: this is the infectious dose. In the vast majority of situations, wind, drafts and ventilation reduce the concentration of viruses in the air, which significantly lowers the risk of infection. On the other hand, a greater risk seems to exist in intensive care situations, in premises where caregivers remove their protection and in hospital toilets. “

Opinion of the High Council for Public Health

After a request from the DGS, the HCSP therefore produced a new opinion, dated July 23: “Sars-CoV-2: updating of knowledge on the transmission of the virus by aerosols.” Conclusion ? “The HCSP considers that after updating the data in the literature, airborne transmission of the Sars-CoV-2 virus should be considered in enclosed spaces, in particular poorly ventilated and insufficiently ventilated, and in outdoor gatherings.” And to urge the public to wear a mask “In all enclosed public and private collective places as well as in the event of a gathering with a high density of people outdoors in order to limit the emission of respiratory particles.”

More specifically, the High Council cites several scientific studies published in recent weeks on the subject. One, published in early April in Nature concludes that “Aerosol transmission is a potential mode of transmission of coronaviruses, such as influenza and rhinoviruses.” The results ofanother, published in June 2020 from laboratory experiments, suggest that the“Infectivity and virionic integrity [du Sars-CoV-2] can be kept for up to 16 hours in aerosols of a breathable size ”.

The HCSP also refers to a literature review produced by the Canadian National Collaborating Center for Environmental Health (funded by the Public Health Agency of Canada) regarding “Risks and precautions associated with Covid-19” as part of choral singing. The CCNSEA notes in particular that “More and more, it is believed that transmission by small droplets or by aerosols produced during speaking, singing, shouting or breathing is a major route of contagion. […] Aerosol transmission could occur in contexts where particles accumulate in closed, unventilated rooms where many people are gathered for a long period ”. In the opinion of the HCSP, some case studies follow which have “Describes the occurrence of contamination by the Sars-CoV-2 virus of people gathered in confined spaces”.

In the laboratory, in the hospital, in general

In this opinion, the HCSP therefore identifies studies that point in the same direction: airborne transmission of Sars-CoV-2 is possible. But it is not possible in the same proportions, depending on the situation.

Thus, the High Council writes “take into account” two elements. First, the open letter from scientists mentioned at the beginning of the article. Didier Lepelletier, co-chair of the HCSP Covid-19 permanent working group, points out that this letter was written by physicists, “Who believe that the dichotomy between droplet and microdroplet [aérosol] is irrelevant, for them everything is aerosol ”. What’s more, continues the head of the Bacteriology – Hospital Hygiene Department of the Nantes University Hospital: these physicists “Are based on models, for example in the laboratory, which for some have suggested that the virus could circulate in the form of aerosols”.

Second element considered by the HCSP for its opinion this summer: a position statement from the beginning of July from the WHO. It is fully readable (and in English), or in summary form (in English), tells us the World Health Organization.

“Is the virus spread by aerosols?” wonders the WHO, which distinguishes two cases. On the one hand, in a healthcare setting: “Some medical procedures can produce very small droplets that can stay airborne for longer periods. [par exemple une intubation ou une extubation]. When such medical procedures are performed on people infected with Covid-19 in healthcare facilities, these aerosols may contain the Covid-19 virus. These aerosols can potentially be inhaled by other people if they are not wearing the appropriate personal protective equipment. ”

Another scenario, in the general population (excluding hospitals): “Cases of Covid-19 have been reported in some closed places, such as restaurants, nightclubs, places of worship or workplaces where people can shout, talk or sing. In these cases, aerosol transmission, especially in those closed places where there are overcrowded and insufficiently ventilated spaces where infected people spend long periods with other people, cannot be excluded. ” And the WHO to insist (like the HCSP): “Further studies are urgently needed to study these cases and assess their importance for the transmission of Covid-19.”

Less contagious than chickenpox

“There is never only one mode of transmission of a virus, recalls Didier Lepelletier, but there is always a preferential mode. “ It can be hand-carried, or aerial for example. And among the modes of aerial transmission, there are therefore, schematically, droplets and aerosols. In the current state of knowledge (and for several weeks), “Droplets are a preferential mode of transmission over aerosols”, observes the member of the HCSP.

Several scientists contacted believe that if aerosols were the main vector of Sars-CoV-2, the R0 (initial reproduction number) would be much higher. As it is, for example, for pulmonary tuberculosis or chickenpox (which are transmitted by aerosol). Whose R0 fluctuates around 10 (much more than for Covid-19).

In a recent study published in the British Medical Journal, the authors find that the risk that a person without symptoms (but who can, for example, emit aerosols just by breathing or talking) contaminates those around them depends on the density of people, their activity and ventilation. This is in line with what the High Council expressed in its opinion of 23 July, according to which “Three favorable conditions are to be remembered concerning the transmission of the virus: the conditions of ventilation and air flow; atmospheric conditions (low temperature, humidity); physical activities and efforts practiced in confined spaces ”.

It should be noted that neither the HCSP, nor the WHO (nor the signatories of the forum cited above) explicitly recommend wearing a mask outside of these situations (for example in general, in the street). Still, specialists in these subjects would like to see studies develop to better understand the modes of transmission of this virus.

In summary : aerosols do not appear to be the preferred mode of transmission on Sars-CoV-2. However, certain observations in hospitals or in laboratories suggest that there may be airborne transmission, without there being a consensus on the risk or the probability of it occurring. In the general population, there is no proof or scientific measurement of the risk of airborne transmission, but this risk is probable according to the scientific community, and it is all the more important in poorly ventilated environments or outdoors in the event of large gatherings. Hence an incentive, under these conditions, to wear the mask in a closed environment, under the precautionary principle.


Fabien Leboucq

.

“There is no reason for schools to become reservoirs for viruses”

School, reservoir for viruses: chiseled by seasonal epidemics of influenza and gastroenteritis, the image dies hard. Except with the Sars-CoV-2, the rule suffers exception. According to the researchers, the child is not the main vector of propagation of the epidemic. Subject to compliance with barrier gestures and screening of patients, Professor Michel Tsimaratos, head of the multidisciplinary pediatrics department at the Marseille hospital of Timone (AP-HM), believes that returning to class does not compromise the control of the epidemic. It is even, according to this member of the European Academy of Pediatrics, a public health imperative.

Read also Covid-19: before the start of the school year, Blanquer beats the recall

Is it dangerous for children to go back to school?

I am convinced not. Data from Public Health France attest to this: children contract Covid less easily than adults. Importantly, when they are infected, the vast majority of children report little or no symptoms. In children under 15 years of age, severe forms, such as Kawasaki disease, which we do not yet know very well why they are linked to an infection by Sars-CoV-2, are extremely rare.

But does the risk of contamination exist?

We cannot exclude it. There is now a scientific consensus to say that the risks of transmission of the virus are high in closed places with high human density. It is clear between adults. It is less so among children. According to several American and German studies, the viral load of an infected child is comparable to that of an adult. We can therefore think that their contagious potential is similar. But there is also a noticeable difference: Since they often have few or no symptoms, children might be less likely to project infectious droplets into their surroundings.

Read also In Suèvres, the pupils “have forgotten what school is”

What precautions should I take?

If the barrier gestures are respected, starting with hand washing, there is undoubtedly much less risk of transmission from child to child and from child to adult – therefore from student to teacher. Conversely, the risk of a child being infected by a sick adult justifies, from my point of view, the wearing of a mask by teachers and school staff. In the family context, this implies taking precautions, the contagiousness being maximum two days before and up to eight days after the appearance of the first symptoms. The case of a sick parent should also be considered. It would then be preferable for her children to stay at home for fourteen days. To the parents of my patients, I say: put your children in school. On the other hand, protect yourself by putting on a mask outside the home and washing your hands frequently, especially if there are elderly people or people with co-morbidities around.

Social distancing cannot be ensured in schools, should children be required to wear a mask to limit the circulation of the virus?

Not at any age. In most countries, wearing a mask is recommended from the end of primary school. Before, it’s probably unnecessary. The child would spend his time touching it with his hands, which would make it ineffective! The mask can be recommended when there is a possible concentration of sick people. But a class is not the same as a meeting between people who meet occasionally. In a classroom, if no child has symptoms within a week or two of re-entry, the risk of transmission is probably very low. However, if children go to school by public transport, it is advisable for them to put on a mask from the age of 10 or 11.

In the event of proven contamination of a student or a teacher, do you think it wise to close the establishment?

No. If a child is symptomatic, they should be tested and kept at home as long as they are contagious. Obviously, if there are several children who declare the Covid at the same time, the question may arise of screening the whole class and placing it in quarantine. But if no one has any symptoms, I don’t see the point: the most likely is that the children will immunize themselves gently. Subject to respect for barrier gestures, there is no reason for schools to become reservoirs for viruses. It is undoubtedly easier there than in other places to go up and break the chains of contamination. In my opinion, closing schools poses a much greater risk to children’s health than Covid.

What do you mean ?

We will have to closely study the place that screens and desocialization occupied during confinement. For children, starting with the youngest, socialization is essential. At this stage of their development, they suffer much more from the scarcity of social interactions, from their intellectual and cultural environment, than from Covid. In my opinion, the risks of dependence on screens and certain forms of abuse present a greater health risk for them than that linked to the virus.


Nathalie Raulin

.

Coronavirus: a mutation and many questions

The coronavirus is mutating, and some experts have raised hopes of a virus that has become less formidable. Some point to the situation in France where the number of infected people has increased markedly since the beginning of August (3,607 additional cases on Saturday, 4,500 Friday, 4,771 Thursday, etc.), without this resulting – for the moment – in a significant influx. of patients in hospitals. A less dangerous Covid-19? “No scientific argument comes to support this theory, alas”, responds firmly the Minister of Health, in an interview with JDD. On August 16, Malaysia’s director general of health announced that a mutation of the coronavirus has been detected in two new sources of contamination in the country. The mutated form has also been noted in Singapore recently. But this variant of Sars-CoV-2 is not new: scientists saw it appear months ago and are tracking its progress across borders. The coronavirus circulating today is

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Camille Gevaudan

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Is it true that nicotine users contract Covid-19 less?

Hello,

Numerous case studies demonstrate this unequivocal : smokers who get Covid-19 have a risk greatly increased to develop severe forms of the disease. In this work, we find that the proportion of smokers is two to four times higher in severely ill patients than in those with a moderate form of the disease.

On the other hand, several publications relayed since the beginning of April report a counterintuitive phenomenon: in several countries, the proportion of smokers infected with SARS-CoV-2 would be lower than the proportion of smokers at regional or national level. The Minister of Health, Olivier Véran, recently mentioned this data.

In France, works being published conducted on a limited number of patients at the Pitié-Salpétrière, as well as a study in a school environment in Crépy-en-Valois (prepublished this April 23), also reported this statistical trend.

Many potential limits

Note now that the link between smoking status and propensity to be infected does not appear in all research. So in a recent study published in the Jama, involving 5,700 New York patients hospitalized for Covid-19, the proportion of smokers was analogous to that observed in the regional population.

The first studies were met with skepticism, not without reason. Indeed, many of these works have sometimes significant biases.

First limitation present in all studies (with the exception of French studies): the age parameter of hospitalized patients. Indeed, a significant proportion of patients with severe forms of Covid-19 are over the age of 65. The prevalence of smokers decreases very strongly with age (for example, in France, 65-75 year olds smoke 2.5 times less than the general population).

In the study conducted at Pitié-Salpêtrière, taking into account the age and sex of the patients, smokers nevertheless appeared to be four times less likely than non-smokers to be Covid +. A rate observed both in hospitalized patients and in patients treated on an outpatient basis. However, in order to draw more solid conclusions, these results should have been put into perspective with the smoking profile of patients who usually attend this hospital, at the same periods in previous years.

Another parameter that seems to be excluded from most analyzes: the socio-economic profile of the groups studied, which can strongly influence the expected proportion of smokers. A limitation mentioned by the authors of the French study, who established their calculations “Assuming that the population studied who lives in a limited area around a Parisian hospital has the same smoking habits as the French population in general”, and who note that “Healthcare workers were overrepresented in the outpatient group due to routine workplace testing when they became symptomatic”. The study conducted at Crépy-en-Valois seems to take this parameter into account. And its results are consistent with the Pitié Salpêtrière study.

Third important pitfall: the quality of the information collected is not always there … far from it. In some studies used by epidemiologists to conduct their analyzes, the smoking status of the sickest Covid + patients was simply not informed. Commentators have also noted that one of these studies considered individuals to be “non-smokers” less than 30 packages per year – preventing any comparison with national statistics which relate to all cigarette consumers.

For its part, the study conducted at Pitié-Salpêtrière seems to consider as “former smoker” any person who had quit smoking at the time of his hospitalization … without mentioning the hypothesis that patients may have stopped smoking because of the first Covid-19 symptoms! A point which would considerably influence the results. Requested by CheckNews, Zahir Amoura, author of this work, has not yet commented on this point.

Is the phenomenon biologically plausible?

The interpretation of these statistics, as well as the extent of the associated phenomenon, are still questionable.

Researchers, however, have begun to explore the hypothesis of a direct causal link between smoking status and primary SARS-CoV-2 infection. The question arises indeed: from a physiological point of view, is it plausible that lungs exposed to tobacco are less permeable to this coronavirus? Could nicotine be involved in the phenomenon?

A possible link with the ACE2 receiver?

SARS-CoV-2 infects cells by binding to the ACE2 receptor, abundant on the surface, in particular, the cells of the mucous membranes and the alveolar pulmonary tissue. The expression of the gene corresponding to ACE2 is not identical in smokers and in non-smokers. Based on animal models, smokers have long been considered to express less ACE2 – which suggests a simple explanation for the phenomenon: less ACE2 induces a lower propensity for infection.

But recent data, which seem to be corroborated by new researchsuggest that in humans, smoking is associated with a higher expression of ACE2. A higher propensity for coronavirus infection would therefore be expected. The epidemiological observations mentioned above, suggesting a protective effect of tobacco, would therefore raise a paradox.

Several explanatory hypotheses have been formulated. Some authors have advanced that in all patients, infection with SARS-CoV-2 would decrease the availability of ACE2 receptors in the lungs. The biological processes that usually mobilize these receptors would be hindered, leading to various symptoms of the disease. People with more ACE2, even if they were infected, would develop fewer symptoms. However, this interpretation is challenged by the Crépy-en-Valois study, where the diagnosis of infection was made on a blood test, and not on a simple clinical assessment of symptoms.

According to other works, the nAChR nicotinic receptor could modulate the activity of ACE2. Could stimulating nAChR make infection through ACE2 more difficult? This fact is not yet proven. “The possibility of a reciprocal modulation between ACE2 and the nicotinic receptor is an interesting scientific question for which we have no answer”, insists Professor Jean-Pierre Changeux, co-author of a scientific article inviting this hypothesis to be explored.

La Pitié-Salpêtrière has announced the launch of several clinical trials in this direction. The first, conducted on caregivers, aims to compare the infection rate between a group carrying nicotine patches and a group carrying placebos patches. More trials need to be done on Covid + patients in hospital to assess whether nicotine affects the course of the disease – especially in smokers who are forced to quit as a result of hospitalization.

Nicotine and vaping: preliminary data not very encouraging

The return of associations of electronic cigarette users does not seem to go in this direction, however. According to the analysis of a questionnaire sent in early April to several thousand members of the AIDUCE and SOVAPE associations, the rate of patients suspected of being Covid + was similar whether or not there was nicotine consumption – around 2.5 %. “Although it concerns nearly 10,000 people, this citizen survey is inconclusive on a major protective effect of nicotine, note the associations in a press release. The first data show no major positive or negative effect of vaping when faced with the risk of contracting Covid-19 for vapers and their entourage. ”

Tobaccoologist Bertrand Dautzenberg, who had encouraged these associations to explore this hypothesis, notes on Twitter that the data was not collected under conditions “Respecting all the obligations of scientific studies”. He nevertheless considers that they are not showing strong signs of a beneficial effect of nicotine in reducing Covid-19 levels. ” He invites an analysis of the Health Database to further explore this hypothesis.

No reason to start smoking

The tobacco specialist recalls “That tobacco certainly brings a negative effect greater than that of a small benefit which is not confirmed at all”. “This leads to encouraging all doctors to advise and support smoking cessation for all smokers.” The authors of the Crépy-en-Valois study abound in this sense, recalling that tobacco is responsible for 75,000 deaths per year in France. “Smoking cannot therefore be offered as a way of protecting oneself against the new coronavirus”, they insist.

Unsurprisingly, this finding is similar to that of the authors of a review on the complications of Covid-19 related to smoking. “Risk factors for severe forms of Covid-19 (pulmonary and cardiovascular disorders, diabetes, etc.) are more common in smokers. Smokers with comorbidities should quit smoking by all means. ” They also observe that confinement can lead to social isolation and psychological distress that increase the need for smoking. [En outre], smoking is more prevalent among the economically less advantaged groups, and they are potentially more at risk for Covid-19. ”

For its part, the association Alliance contre le tabac urged the greatest caution with regard to speculative information in circulation. In the absence of more evidence, nicotine users, “Should not expect to be more protected than the population from the current epidemic”, she recalls. In addition, she advises non-smokers to use nicotine substitutes. A warning also formulated by the promoters of the Pitié-Salpétrière study or by the Minister of Health.

In summary

Although well publicized, epidemiological observations associating smoking and the risk of developing the symptoms of Covid-19 are difficult to interpret at this time. Under the hypothesis of a real cause and effect link, the biological mechanisms mentioned in the press are still hypothetical. None have yet been formally tested.

Listen to the weekly behind the scenes podcast of CheckNews. This week: Covid-19: what are the real figures for deaths in intensive care?

Jérôme Salomon, the Director General of Health, mentioned a mortality of 10% in intensive care of patients hospitalized for Covid-19. In this episode, Luc Peillon explains why this figure is largely underestimated.


Florian Gouthière

.

“Around May 11, the epidemic will still be there” – Release

“Around May 11, the epidemic will still be there” Liberation.

The economic debacle of the coronavirus in graphics | Economy

The paralysis of air traffic, especially commercial flights, is a direct consequence of the coronavirus pandemic, which has confined more than a third of the world population. In the first four months of the year, world traffic has fallen by 60%, according to Eurocontrol. This decrease has been especially pronounced in the European Union, where the number of flights has been reduced by 88% on average, according to the same data. In Spain, the reduction is almost 95%. The pandemic has also affected maritime traffic, which began to notice the first declines in late January, especially since China accounts for a third of global container traffic. In fact, in the first two months of the year, the Asian giant’s international trade fell 9.6% year-on-year, according to data published by the country’s General Administration of Customs.


Global air traffic falls into

the first four months of 2020

WHO declares

the pandemic

On January 9 they registered 185,552 flights *; on April 15, 74,954

* Commercial passenger, cargo, private, helicopter, drone, military, government and health flights.

Flights are reduced in Spain

Fall in April from the previous year

WHO declares

the pandemic

On March 12 flights decreased in Spain a 10.5%; on the 17th, a 43.7%, and since March 28 the fall exceeds the 90%

Airports empty

in Madrid and Barcelona

WHO declares

the pandemic

Flight drop compared to 2019.

March 1: Madrid-Barajas, 4.4%; Barcelona-El Prat, 0.8; April 15: Barajas, 93%; El Prat, 96%

Global air traffic falls into

the first four months of 2020

WHO declares

the pandemic

On January 9 they registered 185,552 flights *; on April 15, 74,954

* Commercial passenger, cargo, private, helicopter, drone, military, government and health flights.

Flights are reduced in Spain

Fall in April from the previous year

WHO declares

the pandemic

On March 12 flights decreased in Spain a 10.5%; on the 17th, a 43.7%, and since March 28 the fall exceeds the 90%

Airports empty

in Madrid and Barcelona

WHO declares

the pandemic

Flight drop compared to 2019.

March 1: Madrid-Barajas, 4.4%; Barcelona-El Prat, 0.8; April 15: Barajas, 93%; El Prat, 96%

Global air traffic falls into

the first four months of 2020

Flights are reduced in Spain

Fall in April from the previous year

WHO declares

the pandemic

WHO declares

the pandemic

On January 9 they registered 185,552 flights *; on April 15, 74,954

On March 12 flights decreased in Spain a 10.5%; on the 17th, a 43.7%, and since March 28 the fall exceeds the 90%

* Commercial passenger, cargo, private, helicopter, drone, military, government and health flights.

Airports empty

in Madrid and Barcelona

WHO declares

the pandemic

Flight drop compared to 2019.

March 1: Madrid-Barajas, 4.4%; Barcelona-El Prat, 0.8; April 15: Barajas, 93%; El Prat, 96%

Global air traffic falls into

the first four months of 2020

Flights are reduced in Spain

Airports empty

in Madrid and Barcelona

Fall in April from the previous year

WHO declares

the pandemic

WHO declares

the pandemic

WHO declares

the pandemic

On January 9 they registered 185,552 flights *; on April 15, 74,954

On March 12 flights decreased in Spain a 10.5%; on the 17th, a 43.7%, and since March 28 the fall exceeds the 90%

Flight drop compared to 2019.

March 1: Madrid-Barajas, 4.4%; Barcelona-El Prat, 0.8; April 15: Barajas, 93%; El Prat, 96%

* Commercial passenger, cargo, private, helicopter, drone, military, government and health flights.

The confinement of citizens in their homes has also had an impact on road traffic, which has experienced a notable decrease, visible daily on the streets of any city. Last Friday, private car traffic in Madrid and Barcelona was around 65% lower compared to a February business day. These are the last images available today, April 17th.

Press to see the most recent images

Madrid

Plaza de Cibeles

Plaza de Cibeles

Puerta de Alcalá

Puerta de Alcalá

Columbus Square

Columbus Square

Barcelona

Ramblas and Columbus monument

Ramblas and Columbus monument

Plaça Urquinaona

Plaça Urquinaona

Plaça Antonio López

Plaça Antonio López

Empty streets have in turn influenced air quality. According to data compiled by Ecologists in Action, the average of gas emissions from traffic during the month of March was 55% lower than the average for the last period.

Blow to the job

Coronavirus has had a devastating effect on the labor market. Since the closure of the schools was announced on March 9, until the end of the month, Social Security lost more than 800,000 members, leaving a total of 19 million the number of contributors. It is the same number of people who stopped trading between October 2, 2008 and February 27, 2009, the period considered as the zero zone of the Great Recession caused by the Lehman Brothers bankruptcy. The number of unemployed rose in the same period by 302,265, according to data from the Ministries of Labor and Social Security. In addition, 3.5 million workers have been affected by an ERTE, double that between 2009 and 2019.


The effects of the coronavirus

shoots the total of unemployed

In February, 3,246,047 unemployed; in March, 3,548,312

Source: Ministry of Labor.

The increase in March more than 300,000 unemployed is the largest since 2010

Source: Ministry of Labor.

Workers descend

in Social Security

The average number of members in February was 19,250,229; in March, 19,006,760

Source: Ministry of Labor.

Membership drop in March

Regarding February (last day of the month)

The lost of 833,979 jobs is the worst figure in the statistical series.

Source: Ministry of Labor.

The effects of the coronavirus

shoots the total of unemployed

In February, 3,246,047 unemployed; in March, 3,548,312

Source: Ministry of Labor.

The increase in March more than 300,000 unemployed is the largest since 2010

Source: Ministry of Labor.

Workers descend

in Social Security

The average number of members in February was 19,250,229; in March, 19,006,760

Source: Ministry of Labor.

Membership drop in March

Regarding February (last day of the month)

The lost of 833,979 jobs is the worst figure in the statistical series.

Source: Ministry of Labor.

The effects of the coronavirus

shoots the total of unemployed

In February, 3,246,047 unemployed; in March, 3,548,312

The increase in March more than 300,000 unemployed is the largest since 2010

Source: Ministry of Labor.

Source: Ministry of Labor.

Workers descend

in Social Security

Membership drop in March

Regarding February (last day of the month)

The average number of members in February was 19,250,229; in March, 19,006,760

The lost of 833,979 jobs is the worst figure in the statistical series.

Source: Ministry of Labor.

Source: Ministry of Labor.

The effects of the coronavirus

shoots the total of unemployed

Workers descend

in Social Security

Membership drop in March

Regarding February (last day of the month)

In February, 3,246,047 unemployed; in March, 3,548,312

The increase in March more than 300,000 unemployed is the largest since 2010

The average number of members in February was 19,250,229; in March, 19,006,760

The lost of 833,979 jobs is the worst figure in the statistical series.

Source: Ministry of Labor.

Source: Ministry of Labor.

Source: Ministry of Labor.

Source: Ministry of Labor.

And if the effects during the first weeks of confinement have been devastating, the forecasts are not hopeful. The IMF predicts that Spain concludes 2020 with 20.8% unemployed.

The sectors

Although it is premature to estimate the economic losses from the coronavirus pandemic, the comparison with the 2003 SARS epidemic predicts devastating consequences. Then, the virus, which sickened more than 8,000 people and killed 774, caused worldwide losses of between 35,000 and 50,000 million euros, according to different analyzes. SARS-CoV-2 has already affected more than two million people in four months and has killed more than 150,000. Tourism, hospitality, commerce or the automotive sector are among the most affected sectors – although there are many more. This is the decline they have suffered during the crisis:


The fall of tourism

planned for 2020

In the case of a scenario without activity in establishments dedicated to tourism between April and June.

Biggest decrease in tourism activity in 2020: Balearic Islands -41%

Billing of the sector

of the hospitality industry

Expected fall after the closure of establishments.

Billing planned for

2020 before the health crisis

124,000

millions of euros

After the closing of

establishments

-40,000

millions of euros

After the closing of

establishments

-30% / – 40%

Bars, restaurants and accommodation: 314,000; workers: 1,700,000

Source: Hospitality of Spain / B & C and EY.

The sale of cars falls

at a level never recorded

Vehicle registration in March

Car registration. March 2019: 122,659; March 2020: 37,644

Lower electricity consumption

that in March 2019

March 23 (second

week of confinement)

April 6 (second week of

paralysis of non-essential activities)

Source: Red Eléctrica Española (REE).

The fall of tourism

planned for 2020

In the case of a scenario without activity in establishments dedicated to tourism between April and June.

Biggest decrease in tourism activity in 2020: Balearic Islands -41%

Billing of the sector

of the hospitality industry

Expected fall after the closure of establishments.

Billing planned for

2020 before the health crisis

124,000

millions of euros

After the closing of

establishments

-40,000

millions of euros

After the closing of

establishments

-30% / – 40%

Bars, restaurants and accommodation: 314,000; workers: 1,700,000

Source: Hospitality of Spain / B & C and EY.

The sale of cars falls

at a level never recorded

Vehicle registration in March

Car registration. March 2019: 122,659; March 2020: 37,644

Lower electricity consumption

that in March 2019

March 23 (second

week of confinement)

April 6 (second week of

paralysis of non-essential activities)

Source: Red Eléctrica Española (REE).

The fall of tourism

planned for 2020

Billing of the sector

of the hospitality industry

In the case of a scenario without activity in establishments dedicated to tourism between April and June.

Expected fall after the closure of establishments.

Billing planned for

2020 before the health crisis

124,000

millions of euros

After the closing of

establishments

-40,000

millions of euros

After the closing of

establishments

-30% / – 40%

Biggest decrease in tourism activity in 2020: Balearic Islands -41%

Bars, restaurants and accommodation: 314,000; workers: 1,700,000

Source: Hospitality of Spain / B & C and EY.

The sale of cars falls

at a level never recorded

Lower electricity consumption

that in March 2019

Vehicle registration in March

March 23 (second

week of confinement)

April 6 (second week of

paralysis of non-essential activities)

Car registration. March 2019: 122,659; March 2020: 37,644

Source: Red Eléctrica Española (REE).

The fall of tourism

planned for 2020

Billing of the sector

of the hospitality industry

The sale of cars falls

at a level never recorded

Lower electricity consumption

that in March 2019

In the case of a scenario without activity in establishments dedicated to tourism between April and June.

Expected fall after the closure of establishments.

Vehicle registration in March

Billing planned for

2020 before the health crisis

124,000

millions of euros

After the closing of

establishments

-40,000

millions of euros

After the closing of

establishments

-30% / – 40%

March 23 (second

week of confinement)

April 6 (second week of

paralysis of non-essential activities)

Biggest decrease in tourism activity in 2020: Balearic Islands -41%

Bars, restaurants and accommodation: 314,000; workers: 1,700,000

Car registration. March 2019: 122,659; March 2020: 37,644

Source: Hospitality of Spain / B & C and EY.

Source: Red Eléctrica Española (REE).

Work has already announced that it is studying increasing ERTE force majeure in the sectors most affected by the crisis. In addition, the resumption of activity in Spain, once the covid-19 epidemic allows it, will be carried out in two stages: the first will affect the productive sectors and will take place until the summer, and the second will include the sectors most affected by the crisis and will last until the end of the year, which means that, according to government forecasts, sectors such as tourism or hospitality will take months to recover.

The reaction of the markets

Stock market losses from the coronavirus total hundreds of billions. Although stimulus from governments and central banks has slightly slowed the decline, investors’ fear of the collapse of companies has hit the main parquets hard:


The Ibex 35

falls to zone

minimum

Brusque

fall of the

Dow Jones

2/19/2020: 10,083 Max.

03-16-2020: 6,107 Min.

12-2-2020: 29,551 Max.

03-23-2020: 18,591 Min.

Evolution of

the cousin of

risk

The oil,

in minima

20 years

Dollars per barrel Brent

6-1-2020: 68.91 Max.

3-31-2020: 22.74 Min.

3-18-2020: 146.3 Max.

03-26-2020: 84.0 Min.

Gold scales

as active

refuge

04-14-2020: 1,768 Max.

03-16-2020: 1,461 Min.

The Ibex 35

falls to zone

minimum

Brusque

fall of the

Dow Jones

2/19/2020: 10,083 Max.

03-16-2020: 6,107 Min.

12-2-2020: 29,551 Max.

03-23-2020: 18,591 Min.

Evolution of

the cousin of

risk

The oil,

in minima

20 years

Dollars per barrel Brent

6-1-2020: 68.91 Max.

3-31-2020: 22.74 Min.

3-18-2020: 146.3 Max.

03-26-2020: 84.0 Min.

Gold scales

as active

refuge

04-14-2020: 1,768 Max.

03-16-2020: 1,461 Min.

The Ibex 35

falls to zone

minimum

Brusque

fall of the

Dow Jones

Evolution of

the cousin of

risk

2/19/2020: 10,083 Max.

03-16-2020: 6,107 Min.

12-2-2020: 29,551 Max.

03-23-2020: 18,591 Min.

3-18-2020: 146.3 Max.

03-26-2020: 84.0 Min.

The oil,

in minima

20 years

Gold scales

as active

refuge

Dollars per barrel Brent

6-1-2020: 68.91 Max.

3-31-2020: 22.74 Min.

04-14-2020: 1,768 Max.

03-16-2020: 1,461 Min.

The Ibex 35

falls to zone

minimum

Brusque

fall of the

Dow Jones

Evolution of

the cousin of

risk

The oil,

in minima

20 years

Gold scales

as active

refuge

Dollars per barrel Brent

2/19/2020: 10,083 Max.

03-16-2020: 6,107 Min.

12-2-2020: 29,551 Max.

03-23-2020: 18,591 Min.

3-18-2020: 146.3 Max.

03-26-2020: 84.0 Min.

6-1-2020: 68.91 Max.

3-31-2020: 22.74 Min.

04-14-2020: 1,768 Max.

03-16-2020: 1,461 Min.

However, with positive prospects, the Stock Exchange rebounds to the upside. This is what happened after the presentation by the President of the United States, Donald Trump, of a plan to resume the country’s activity in mid-June.

Forecasts: it can still get worse

The most optimistic scenario of the IMF foresees a fall in GDP in Spain of 8%, the worst in its recent history, as long as there are no delays in containing the pandemic or a flare-up that confines part of the planet again. But it is not the only negative indicator. The collapse of fuels – exacerbated by the recently resolved conflict between Russia and Saudi Arabia – and light has brought the CPI to 0%, a figure that has not decreased since August 2016 – the forecast is that it will close the year in -0.3% -. These are some of the apocalyptic economic indicators left by the coronavirus crisis.


Inflation

will close the year

at negative rate

The economy

Spanish is

will collapse

this year

Breaks the

trend of

six years of

I stop on the downside

* IMF forecast

(2020 and 2021)

Source: Ministry

of the Treasury.

* IMF forecast

(2020 and 2021)

Source: Bank

from Spain.

Inflation

will close the year

at negative rate

The economy

Spanish is

will collapse

this year

Breaks the

trend of

six years of

I stop on the downside

* IMF forecast

(2020 and 2021)

Source: Ministry

of the Treasury.

* IMF forecast

(2020 and 2021)

Source: Bank

from Spain.

The economy

Spanish is

will collapse

this year

Inflation

will close the year

at negative rate

Breaks the

trend of

six years of

I stop on the downside

* IMF forecast

(2020 and 2021)

* IMF forecast

(2020 and 2021)

Source: Ministry

of the Treasury.

Source: Bank

from Spain.

The economy

Spanish is

will collapse

this year

Inflation

will close the year

at negative rate

Breaks the

trend of

six years of

I stop on the downside

* IMF forecast

(2020 and 2021)

* IMF forecast

(2020 and 2021)

Source: Ministry

of the Treasury.

Source: Bank

from Spain.

.

Covid-19: Are asymptomatic children a vector of the epidemic?

Hello,

Following Emmanuel Macron’s announcement of the gradual reopening of schools on May 11, many of you asked us about the role of children in the spread of the epidemic. And especially those who have been contaminated and who show little or no symptoms.

Because the fact is now well established: children infected with SARS-CoV-2 develop symptoms of the disease much less frequently than adults. The low rate of positive diagnoses among the youngest could, for this reason, conceal a much higher infection rate. On this subject, works prepublished end of March – who have not yet been independently reviewed – suggest that children in contact with infected individuals are just as likely to be infected as adults under the age of 60.

However, several unknowns remain. First, it is not yet known whether infected children transmit the disease as easily as adults.

On the one hand, contaminations from child to adult are currently unnoticed in the case of asymptomatic contaminations.

On the other hand, little data exists on the infectiousness of the secretions (postillons, sputum) of children without symptoms.

More generally, the infectious potential of asymptomatic individuals, whatever their age, is not yet sufficiently documented – notably due to the difficulty of tracing these cases. At the beginning of April, WHO recalled the risk of contamination during the last days of incubation, at least three days before the onset of symptoms (“pre-symptomatic” transmission). Cases of transmission from carriers who never show symptoms can only be documented with great difficulty.

For all these reasons, the formulations used in the scientific literature devoted to this subject are still conditional (the asymptomatic character “Increases the possibility that children can be facilitators of viral transmission “, Etc.). All authors call for further investigation “On the role of children in the chain of transmission.”

Researchers working on pandemic modeling are just as circumspect. “In studies published since mid-March, including a study prepublished this April 12, we’re looking at several age classes, including a school age class. “, explains Jean-Stéphane Dhersin, researcher at the CNRS and at the Sorbonne Paris Nord University and deputy scientific director of the INSMI (National Institute of Mathematical Sciences and their Interactions). “In the models used [pour estimer les effets des mesures sanitaires], a number of parameters have to be estimated: assumptions are made that people can get the disease, that they can be infectious, and that they can spread it. However concerning children, for the moment, we do not know everything. Particularly because an active test campaign in the general population has not yet been carried out, which is the most effective way of obtaining information. In the models, data are sometimes used that are available for influenza, but it is not known if this is relevant. At this time, it is unclear whether children play an important role in the spread of the epidemic. “

Expert opinions marked by uncertainty

On this dossier, the opinions of experts remain divergent. Assuming asymptomatic children are as contagious as adults, some point out that their social interactions are based on more and more prolonged physical contact than their elders – increasing the risk of infection.

In an interview granted in March to the Swiss daily Time, Arnaud L’Huillier, pediatrician and infectious disease specialist, conversely estimated that children would transmit SARS-CoV-2 less than they would participate in the spread of the flu virus. According to him, the coronavirus in circulation “Affects especially the deep respiratory tract and does not make the nose run, which in children is an important vector for the dissemination of pathogens”.

In an exchange with the AFP, Professor Keith O’Neal, epidemiologist at the University of Nottingham, noted that asymptomatic carrier children were less risky for the community gathered in a school “That entrusted to grandparents” by adults with no other childcare solution.

At the Ministry of National Education, we are told that the risk associated with asymptomatic or pre-symptomatic transmissions in schoolyards “Is one of the points to be discussed with the social partners” to prepare for the end of containment on May 11. “It is still too early to answer these questions”.

This April 14 sure France 2, Minister Jean-Michel Blanquer stressed that going back to school would not be mandatory ” at the end of confinement. “The goal is that between May 11 and July 4 (summer vacation date), we have successfully resocialized […] that allows you to get back into learning. “

In an exchange with the journalists of France Inter, pediatrician Robert Cohen announced on April 14 the launch of a study in Ile-de-France on 600 children, intended to assess the percentage of asymptomatic patients carrying the virus.

cordially

Listen to the weekly behind the scenes podcast from CheckNews. This week: War of masks: does the state use regional orders?


Florian Gouthière

.

Covid-19: can we predict the evolution of the virus thanks to the weather?

A long green stripe on a world map. What if Sars-Cov-2, a virus associated with Covid-19 disease, was different from its congeners Sars-Cov-1 and Mers? What if it was, like the flu, a seasonal virus? For an uninitiated, this does not mean much. But for the virologist that is Mohamed Sajadi, of the Institute of Human Virology, at the University of Maryland, in the United States, and member of the Global Virus Network, this raises other questions: would this new virus be influenced by weather and climate conditions? If so, could we not include these factors in epidemiological models to anticipate the spread of the disease?

The researcher brought together six American and Iranian colleagues who worked with their various skills on this hypothesis. Their conclusion: Covid-19 would spread particularly quickly when subjected to a certain combination of humidity and temperature, which has been found

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Aude Massiot

.