Health

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At the start of the Covid-19 epidemic, it was a simple statistical curiosity. We imagine that people who smoke tobacco are more at risk than the average to be reached, but they seem less exposed vis-à-vis the infection by SARS-CoV-2. Four months later, it’s a new therapeutic path which opens, a hypothesis that the French health authorities take very seriously and which will soon lead to the launch of the first original clinical trials based on nicotine.

The first detailed observation of this paradoxical phenomenon is described by a Chinese research team and published in late February in The New England Journal of Medicine. Scientists then observed, on a group of a thousand patients, a proportion of individuals who smoke lower than that of the Chinese population as a whole (12.6% against 28%). Other similar observations follow. In France, the first data from the Assistance Publique-Hôpitaux de Paris (AP-HP) confirm, out of nearly 11,000 patients with Covid-19, the rate of people who use tobacco is 8.5% – while it is 25% in the general population.

A finding based on solid studies

Why? Are these figures reliable? Dr. Makoto Miyara and Professor Zahir Amoura, two internal medicine specialists from La Pitié-Salpêtrière (AP-HP), wanted to understand. They confirm this paradoxical observation by eliminating statistical biases (such as age and gender) are often confounding factors in this type of observational study. Out of a group of 343 hospitalized patients, only 4.4% smoke tobacco daily. And among the 139 patients followed on an outpatient basis, the proportion is 5.3%.

This study provides a solid basis for asserting that people with a heavy addiction to tobacco use have a much lower probability of developing SARS-CoV-2 infection (of moderate or severe intensity) than the rest of the general population – a risk divided by a factor of five. In other words, we then have statistical evidence confirming that smoking protects against infection by the virus. However, the mystery remains: why?

If the true causes of this protection are not established, it quickly became apparent that the first candidate capable of explaining this phenomenon was the nicotine. We have known for a long time that this toxic substance is naturally present in tobacco leaves, that it acts on the central nervous system and that it is responsible for massive addiction phenomena. A larger group of French researchers was then formed to extend the first observations and conclusions. This group brings together, in addition to members of the AP-HP, others belonging to the CNRS, Inserm, the University of the Sorbonne, the Collège de France and the Institut Pasteur.

The nicotinic receptor, the key to success

Their hypothesis is that infection with SARS-CoV-2 involves a specific molecular structure (a nicotinic receptor), a “key” that facilitates the entry of the virus into cells – a key that would be less functional in people who use tobacco who have become addicted to nicotine. This would explain in particular the frequency observed of certain neuropsychiatric manifestations during Covid-19 – such as the loss of the sense of olfaction and, in certain patients, various neurological disorders which can eventually lead to sudden respiratory arrest. . “SARS-CoV-2 could thus spread from the olfactory mucosa, then from neurons in the brainstem, in some cases going to the respiratory centers”, estimates the research team.

This same hypothesis would still explain some of the spectacular inflammatory or immune manifestations observed in certain patients. Finally, it would help to understand why obesity and diabetes seem to be risk factors and are frequently found in severe cases of Covid-19.

One could imagine that nicotine could be administered via the practice of vaping.

It is this innovative hypothesis which is now developed in biology reviews from the American Academy of Sciences by a small group led by the French neurobiologist Jean-Pierre Changeux, known for his innovative work on this nicotinic receptor.

This theoretical work is already experiencing new extensions: in view of the pandemic health emergency, the people behind this work consider it necessary to rapidly assess the therapeutic impact of their observations and their hypothesis. Of clinical studies should be quickly implemented. Nicotine patches, of the type used to obtain cessation of tobacco addiction, will be applied to different categories of people: caregivers (for preventive purposes), hospitalized patients and others in intensive care. An original enterprise led with the support of Olivier Véran, Minister of Solidarity and Health. One could also imagine that potentially protective nicotine could be administered via the practice of vaping.

A substance that kills

Demonstrate that nicotine protects against Covid-19? The case may be less simple than one might imagine since people who do not smoke can not tolerate (without being victims of headache or vomiting) that very small doses of nicotine which a priori would complicate its use for preventive or curative purposes. Would these low doses be enough to block enough receptors and oppose the viral infection?

As of now, a question of public health is openly posed: how can we ensure that the media coverage of this work, this hypothesis and these perspectives does not have negative consequences? How, by popularizing this scientific approach, not encourage the continuation (or resumption) of daily tobacco consumption? Consumption which would now be perceived as prevention of infection even though its major toxicity has been amply demonstrated (more than 75,000 premature deaths every year in France). How can we explain, at the same time, that people who smoke are less exposed to the risk of Covid-19 without pushing for tobacco consumption? How to promote this experiment without permanently ruining all the efforts of the fight against smoking?

For the time being, the scientists behind this work are trying to warn by explaining that cigarette smoke and the countless toxic substances it contains have no protective effect. The health authorities are doing the same. Professor Jérôme Salomon, Director General of Health, explains that people who do not smoke must in no way resort, on their own initiative, to nicotine substitutes (reimbursed by social security) in the hope of protecting themselves against infection with SARS-CoV-2.

Some fear the effects of media promotion of nicotine substitutes which, if it took place before rigorous testing is conducted, would quickly lead to a situation equivalent to that resulting from the promotion of hydroxychloroquine against the Covid-19.

“You have to be very careful in these observational studies, the smoking rate varies a lot according to sex, country and age, explained Professor Salomon. All this deserves total confirmation. We must not forget the harmful effects of nicotine. Research must be encouraged, but I invite the French not to confuse lines of research with established facts. ”

This is not the least paradox of this approach than hearing today the Director General of Health have to declare: “We strongly advise people not to resume smoking.”

Madrid (EFE) .- The President of the Spanish Government, Pedro Sánchez, announced this Saturday that, if the reduction of coronavirus infections continues, from May 2 You can go for a walk and do sports, in a new step of the de-escalation of the confinement imposed on March 14.

In addition, the socialist Sánchez announced a de-escalation plan for the month of May and June, which will be approved in the Council of Ministers next Tuesday, and that will be raised tomorrow Sunday during a meeting by teleconference with regional presidents.

Mobility will be gradual

This de-escalation will be, according to the Prime Minister, “gradual”, both when resuming activities and mobility, “asymmetric”, since the pandemic has spread unevenly throughout Spanish territory, and “coordinated” by the Government and, always, according to the criteria of the experts.

This announcement comes a day before more than six million children up to the age of 14 can take to the streets in Spain for the first time after 42 days of hard confinement, what Sánchez described as “little relief”.
This measure has been widely demanded by both regional authorities and experts in childhood.

Time restricted

Children can go for a walk for an hour, accompanied by a family member and within a radius of no more than one kilometer.

If this departure does not cause an increase in infections, the following measures will be taken for lack of confidence, that is, the departures on May 2 to exercise and the next phase of de-escalation, but always with caution and knowing that “we have no certainty absolute on how to transit “in that phase, according to the President of the Spanish Government.

Spain is the second country in Europe most affected by the coronavirtus pandemic, after Italy, although according to official data this Saturday the decreasing trend of the pandemic was confirmed and for the second consecutive day there were higher numbers of recovered patients (3,353) than new cases (2,944).

However, there was a slight rebound of eleven deaths compared to yesterday, to add 378, with which the COVID-19 has caused 22,902 deaths in Spain since the start of the pandemic.

Likewise, 2,944 new infections were registered, confirmed by PCR tests, bringing the total to 205,909.

Read: Patients recovered from Covid-19 are not immune to new infection

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Nose cells offer points of attack for corona viruses

The exact transmission pathways of the novel coronavirus SARS-CoV-2 are still not fully understood. So far it was unclear what role the nose plays in the transmission. A Cambridge research team has now shown that certain cells in the nasal and intestinal mucosa have the necessary receptor proteins and enzymes for SARS-CoV-2 to penetrate.

Researchers at the Wellcome Sanger Institute in Cambridge, England, showed that cells in the nose and intestinal mucosa contain the receptor protein ACE2 and the enzyme TMPRSS2. Both are the basic prerequisites for the SARS-CoV-2 coronavirus to enter the cells. At first it was assumed that the virus mainly affects the epithelial cells of the respiratory tract. The findings were published in the two highly renowned specialist journals “Nature Medicine” and “Cell” presents.

Decoded new entry point for SARS-CoV-2

The origin and development (pathogenesis) of COVID-19 is still only known in the beginning. An English research team has now made a major contribution to understanding the new disease. The team identified two specific types of cells in the nose as probable points of infection for SARS-CoV-2. The researchers showed that calyx and ciliated cells in the nose have a high content of receptors that the virus uses to get into our cells.

COVID-19: The role of the nose was unclear

The new findings help explain the high transmission rate of COVID-19 and at the same time offer new approaches for treatments and strategies for containment. It is known that SARS-CoV-2 can spread via droplet infections and that the virus affects the throat and lungs. So far, what role the nose plays was unclear. The research team was now able to determine the exact cell types that are susceptible to SARS-CoV-2 in the nose.

20 different types of tissue were examined

Using the most modern methods, the researchers analyzed 20 different tissue types from non-infected people. These included, for example, cells from the lungs, nasal cavity, eye, intestine, heart, kidney and liver. The researchers looked for which cells express (express) the two most important entry proteins that SARS-CoV-2 needs to infect the cells.

The nose as the most likely first infection route

“We found that the receptor protein – ACE2 – and the TMPRSS2 protease, which can activate the entry of SARS-CoV-2, are expressed in cells of various organs, including the cells of the nasal cavity,” explains study author Dr. Waradon Sungnak. The investigations revealed that especially the mucus-producing goblet cells and cilia in the nose have a high concentration of the necessary entry proteins. “This makes these cells the most likely primary route of infection for the virus,” emphasizes Sungnak.

Viruses can quickly reach nasal cells

“This is the first time that these special cells in the nose have been associated with COVID-19,” adds Dr. Martijn Nawijn from the research team. The location of these cells on the surface of the inside of the nose makes them very accessible to the virus and could also promote transmission to other people. This is a possible explanation for the rapid spread.

Eye and intestinal cells also vulnerable

The two main entry proteins ACE2 and TMPRSS2 were also found in cells in the cornea of ​​the eye and in the intestinal mucosa. This indicates another possible route of infection via the eye and tear ducts and also reveals the potential for a fecal or oral route of transmission.

The atlas of human cells

The investigations were carried out as part of the global “Human Cell Atlas Consortium”. In this ambitious project, all human cells are to be analyzed in order to better understand diseases and health-related processes. More than 1,600 people in 70 countries are involved in this project. The data should be available to researchers worldwide. The project has already provided important insights into COVID-19.

“While we are creating the atlas of human cells, it is already being used to understand COVID-19 and determine which cells are critical for initial infection and transmission,” emphasizes Dr. Sarah Teichmann, the co-chair of the project. According to Teichmann, the findings also provide a basis for developing potential treatments and strategies for containment.

The atlas offers new approaches

“By pinpointing the characteristics of each cell type, the Human Cell Atlas helps researchers diagnose, monitor and treat diseases including COVID-19 in a whole new way,” added Professor Sir Jeremy Farrar, director of the Wellcome Sanger Institute. Cross-border cooperation and the open exchange of research results are crucial for the rapid development of effective diagnostics and therapies to ensure that no country is left behind. (vb)

Important NOTE:
This article contains general information only and should not be used for self-diagnosis or treatment. He can not substitute a visit at the doctor.

What are the advances in research into treatments for Covid-19? Where is the development of a vaccine? Paul Benkimoun, journalist specializing in health issues at World, responded to our readers during our live, April 20.

Read also Coronavirus: more than 20,000 dead and 9.6 million workers on partial unemployment in France, start of deconfinement in certain countries: relive the day of April 20

Marti: Can we be naturally immunized against the coronavirus?

The only way to get immunized, as long as there is no SARS-CoV-2 vaccine, is to get the disease, as is the case with other infections.

Florian: How long does it take to recover from the disease in its mild forms?

In mild forms, the symptoms disappear within a few days, sometimes more (a week), especially if the fatigue has been severe. Some often-present signs, such as loss of smell or taste, take a little longer to disappear.

Zenga89: According to the WHO, “it is not established that the presence in the blood of antibodies to the coronavirus protects from a new infection”. Would this phenomenon, if confirmed, jeopardize the hope of a vaccine?

We do not yet have evidence that the antibodies produced as a result of SARS-CoV-2 infection are able to neutralize it in the body. The question can only be decided once there is sufficient scientific data to establish whether or not there is protection from these antibodies.

Read also Coronavirus: view the increase in mortality in France by age group, sex and department

Antibodies are not our only immune defense. In addition to this so-called “humoral” response, which relies on antibodies, we also have a “cellular” response which passes through a category of specialized white blood cells: CD8 T lymphocytes. The development of a vaccine capable of inducing both an antibody response and a cellular response would resolve the problem of antibodies that are not effective enough against SARS-CoV-2.

Paul: What about announcements about the healed sickness of Covid-19 immunity?

It has not been shown that there is an absence of immunity in cured patients. The uncertainties relate to the fact of knowing if it is really reinfection (infection, followed by a cure, then a second infection), a problem which would be linked to the tests (false negative test in a person “Cured”, then a new positive test) or an apparent disappearance of the virus which could remain in the body, in what is called a reservoir. Again, the accumulation of data will help get out of uncertainty.

Marie: It seems that post-Covid immunity is not certain, which is bad news … Shouldn’t we, then, see a resurgence of cases in China?

The risk of resurgence is linked to the maintenance or not of measures of social distancing (to keep at a distance, wear a mask…) and a policy of detection and isolation of cases of infection, identification of people in contact and their isolation, which is based on the use of diagnostic tests. China maintains such measures. Other countries do the same.

Mistrustful: I just received information that seems to be viral about the role of an intestinal bacteria, the Prevotella… Is this track reliable?

If there is still a lack of knowledge about the new coronavirus, it is firmly established that it is the agent that causes Covid-19. Does this infection cause changes in the intestinal bacterial flora, including Prevotella is part of it? This has not been established and does not appear to be a determining factor in the Covid-19.

Read also This canine coronavirus vaccine has nothing to do with SARS-CoV-2

Koikilenkoute: To my knowledge, only one diagnostic test is 99% reliable, it is the pulmonary scanner. Why is it never mentioned in government communications?

If it is preferable a priori to have a diagnostic certainty, it is necessary to measure the quality of medical information in the light of practical aspects. A lung scanner can diagnose lesions in the lungs, but the first information sought is whether a person is infected with SARS-CoV-2. A strong presumption may exist on the basis of clinical signs (fever, fatigue, cough, but also loss of smell, taste …) and the notion of contact with an infected person. A PCR test after sampling from the nose will identify SARS-CoV-2. The scanner has no relevance for the mild forms which represent the vast majority of infections with this new coronavirus.

Bibi: I still do not understand that the President of the Republic could have said that systematic screening had “no sense”. In the face of an invisible enemy, isn’t the first answer to try to locate it, and therefore to practice large-scale tests to detect asymptomatic carriers?

The president and the executive have not chosen to explain the limitations on the ability to test massively, and to recognize that the strategy has adapted to these limitations. The speech justified the choice not to systematically test otherwise. The same was true for masks. However, one must take into account a logic of feasibility. Systematically testing people in contact with a case, even if they have no symptoms, is essential. Yes “Test the asymptomatic” means testing the entire population, this is impractical, since these tests will also have to be repeated.

Chab12: What are the reasonable times to expect a vaccine?

Over a hundred vaccine trials have started worldwide, as an article on our site specifies today. Getting started means starting a long process, consisting of several steps to ensure the safety of the vaccine candidate, then the fact that it elicits an immune response and then that this immune response protects well against infection.

It is impossible, unless taking unacceptable risks, to skip these steps first on animal models and then in humans, before launching large-scale production – because it will require one or more vaccines accessible worldwide – and proceed with the vaccination. Some manufacturers use a technique with messenger RNA, which shortens the time, usually around eighteen months, but it seems very unlikely to have a ready-to-use vaccine on a large scale before 2021 .

Article reserved for our subscribers Read also Covid-19 vaccine: first human trials started

CD: It was said a few weeks ago that certain forms of the disease mainly affect the digestive system, causing diarrhea in particular. Is this symptom associated with the most common symptoms (fever and cough), and are these forms of the disease mild or severe?

This sign has been described in Chinese publications and has also been found outside of China. It is not the most common symptom and has not been shown to be a sign of any particular severity.

Suzanne: Are pregnant women considered to be at risk who are likely to remain confined? A teacher and five-month pregnant, I wonder if it will be prudent to resume classes in May.

Yes, a pregnant woman is considered to be at risk since Covid-19 has not been shown to be safe for her and the unborn child. This therefore implies more restrictive measures than for another person.

Article reserved for our subscribers Read also Coronavirus: on the trail of the “pangolin connection”

Very calm and healed: We hear about tests with the BCG vaccine against the coronavirus. If this vaccine is effective, why should the population already vaccinated (which I imagine to be large) not already be protected?

The use of BCG to stimulate the immune response is the subject of a study in France. Having been vaccinated, sometimes a long time ago, which is the case for older people at higher risk of developing a serious form, is apparently not enough to provide protection. As has been done in other diseases, it is a question of giving new stimulation to the immune system.

Julie: Do we have any information regarding the genetic stability of the virus? Does it mutate quickly?

At this stage, there have been no scientific publications reporting significant mutations in the virus that could alter the consequences of the infection.

Questioner: What about Professor Raoult’s protocol?

The publications aiming to make this protocol effective have serious shortcomings which do not allow conclusions to be drawn. Publications, not all of good quality, go in the opposite direction and do not find any efficacy of the hydroxychloroquine-azithromycin combination. More reliable results will come with larger, state-of-the-art studies.

Read also Coronavirus: New Caledonia deconfines from April 20

False negative: Do we have more details on the percentage of false negative virological tests and therefore on the reliability of these tests when they will be an important element of deconfinement?

Some tests have questionable reliability, their sensitivity could drop as low as 30%, but other serological tests are being developed, among others by the Institut Pasteur, which should be much more reliable.

Soloforak: The President of Madagascar announced yesterday the discovery and distribution of a plant-based preventive and curative medicine, artemisia. What credibility should be given to this treatment?

This is indeed the announcement that was made by the Madagascan president. The use of herbal teas based on artemisia is promoted by some against malaria because the most recent treatments are derived from this plant, but this is far from being unanimous among scientists. The relevance of its use as a treatment for Covid-19 is far from having been established.

Article reserved for our subscribers Read also Artemisia: a herbal tea against malaria?

Thierry: Is there international cooperation between laboratories or is it a race for the first to find?

It is precisely to avoid this every man for himself and a jackpot for those who would develop a vaccine that governments and international bodies, starting with the WHO, must already impose that treatments, vaccines and diagnostic tests are available worldwide, which excludes prohibitive prices.

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The large increase in the number of strokes in adults in their thirties and forties in perfect health worries New York doctors, who see a clear link with the coronavirus.

• Read also: All the developments of the pandemic

Physicist J. Mocco, who works at Mount Sinai Beth Israel Hospital, in Manhattan, explained to Washington Post that the number of patients with large brain blockages has doubled during the three weeks of the peak of the pandemic in New York. More than half of the cases had COVID-19 and were about 15 years younger than those with stroke but who did not have the virus.

“Statistically, these people are among the people least likely to have a stroke,” said D^r Mocco, which specializes in the field. For him, the link with COVID-19 is as shocking as it is undeniable.

“It is one of the clearest links and one of the deepest correlations I have seen. It’s a signal far too strong for chance. ”

“We used to think that 60-year-old patients are young to have large occlusions in the vessels,” said Eytan Raz, a neuroradiology assistant at NYU Langone. We’ve never seen so much in people in their 50s, 40s and 30s. ”

The New York fire department also reported recovering four times as many bodies from people who died at home during the peak of the pandemic. Several of them had died of a stroke.

Avenues for research

According to the analyzes which are starting to be available on the subject, the patients infected with the coronavirus have mainly devastating strokes, which cause death or which create irreparable damage.

Several researchers believe that strokes in patients with COVID-19 may be a direct cause of a blood problem that leads to clots all over the body.

As neurologist Thomas Oxley of Mount Sinai has seen, when a clot is removed, others immediately reform around it. These clots can cause pulmonary embolism, heart attacks and strokes, all of which have been on the increase since the start of the pandemic.

At present, specialists cannot say whether these clots are the result of an attack by the virus or a reaction of the immune system.

“In the body’s effort to fight the virus, does the immune system’s response end up causing brain damage?” wonders the D^re Sherry H-Y Chou.

The neurologist at the University of Pittsburgh Medical Center neurologist hopes to find answers in the analysis of the thousands of stroke and neurological complications seen in patients with COVID-19 in 68 medical centers in 17 different countries.

I gave a lecture to schoolchildren about coronovirus. I write down thesis.

1. Like any self-respecting virus, covid-19 carries on its surface (by the way, this is a supercapsid, that is, a piece of the membrane membrane of the cell that generated it) proteins that can bind to specific receptors in the host body. For covid-19, this is:

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