CORONAVIRUS – “It’s been two years, and I still haven’t had the Covid.” While the seventh wave of coronavirus continues to grow, carried by the BA.4 and BA.5 variants, some on social networks rejoice: they would have escaped the pandemic since 2020. But while 200,000 positive cases have been detected in the last 24 hours (figures as of July 5) according to the Minister of Health François Braun, are there really people who will never catch the virus?
“Are there people who have never developed symptoms since the start of the pandemic? Yes. In the long term, are there people who will never have the Covid? Nope.” On this subject, here is what answered the HuffPost, last spring, the virologist and member of the Scientific Council Bruno Lina. And categorical, he still is three months later: “I will tell you the same thing: I do not think it is possible to escape the virus.”
However, details the doctor, several factors explain this feeling of a part of the population, convinced of never having been infected. People who are surely on the wrong track if they think they are definitively immune.
To begin with, Bruno Lina thus evokes the proportion of French people who have been infected with Covid-19 without developing symptoms. Because they were infected before the generalization of tests and they were therefore not counted among the more than 30 million French people declared positive since the start of the pandemic, or simply because they did not had them tested when they were carriers of the virus. “There are bound to be people who will remain asymptomatic, and who will have the feeling that they have never been infected”, specifies the scientist.
Ultimately, impossible to escape contamination
His second argument is to say that the virus is extremely transmissible, and that it is therefore becoming more and more difficult to escape wave after wave. It is in particular this very high transmission capacity which causes, with each collective relaxation of the barrier measures, new peaks of contamination. “With viruses circulating so much in the population, it is clear that they end up affecting everyone.” So much so that for Bruno Lina, “in the long term, in order not to catch it, you would have to be isolated, not meet anyone.” And the virologist concludes: “There may be places on the planet where the virus will take longer to arrive, but it will arrive there.” Especially if we take into account the decline in immunity linked to vaccine injections and past infections which protect less and less over time.
By the way, Bruno Lina dismantles an idea that comes up regularly, namely that it would be a “good thing” to contract the virus now so as to be protected for the rest of the summer and thus not spoil your holidays. “Whenever you can avoid an infection, even if it’s mild, it’s better,” he insists. “There is never a short-term benefit to being infected with a pathogen.” What he summarizes with simplicity: “The advantage of being infected is that you are protected against this pathogen. But if you are not infected, you are also protected.”
The only nuance brought by the member of the Scientific Council is to say that it is indeed less risky “to be infected by a pathogen which we know is less dangerous than the others”. Like the BA.2 variant, which caused far fewer serious forms in the spring than its predecessors at the start of the epidemic. And the same goes for the forms of the virus that are currently circulating, which certainly send elderly people or those suffering from comorbidities to the hospital, as the infectious disease specialist noted. Karine Lacombe on France Interbut which in no way cause the same mortality as the viruses of 2020 and 2021. And that too thanks to the immunity developed in 30 months.
So much for the general considerations on a pandemic which has, for two and a half years, easily proven its ability to gain ground. But other elements deserve to be added to the file because at the individual level, certain organizations could also be better equipped to deal with Sars-CoV-2. “Completely exceptional cases”, insists Bruno Lina from the outset, referring to “individuals with better defenses, at the margin”, but in no way large groups of the population who would be totally immune.
To illustrate this idea, the doctor reminds us that certain rotaviruses (responsible for gastroenteritis) fail, for example, to infect very specific blood groups. “But for the time being, whether on the genome, the HLA system or the blood group, we have not found any proof of this with regard to covid-19”, he assures, while this track had been considered from the first hours of the pandemic, in 2020.
Then comes another series of hypotheses, mentioned last April to the HuffPost by Cecil Czerkinsky, immunologist and research director emeritus at Inserm. He imagined a whole series of cases still to be proven and in which genetic mutations or a specific immune response would make certain individuals more ready to eliminate the Covid. This does not mean that they would be immune, but which could explain why they never develop symptoms or even test positive.
T lymphocytes, Spike protein… Individuals may be unequal in the face of the virus
These are the avenues recently developed by Zania Stamataki, a researcher specializing in Covid who has never tested positive despite an environment where the virus has circulated a lot. In a column published by The Guardianthis immunologist quickly brushes aside the possibility of never having been in contact with the virus, which leads her to look into the idea of a more effective response from certain organisms.
She evokes here a first theory, that of T lymphocytes which would have already developed a form of immunity by fighting in the past other coronaviruses than Sars-CoV-2. This memory would then prove effective against the Covid. Zania Stamataki recalls that this is how the body learns to fight the common cold, which becomes a banal infection from infections to infections. In this case, these pre-existing defenses, reinforced by the body’s first victory over the Covid, then the different doses of vaccine, could have provided it with a whole “arsenal” protecting it against the Covid, she suggests.
The other track evoked jointly by Cecil Czerkinsky and Zania Stamataki follows another line of reasoning and concerns the Spike proteins on which Sars-CoV-2 binds. Some organisms would have less on the surface of their cells, which would decrease the number of potential attachments of the virus. This would make individuals less vulnerable to infection. To support her thinking, the researcher cites the fact that children, who have fewer of these proteins, have developed fewer serious forms than adults.
Scientific answers are still awaited
And Zania Stamataki goes even further, by advancing a subsidiary hypothesis: what if certain organisms – including his own – had proteins on which the virus cannot even attach? This would be the result of a polymorphism, or the different expression of certain proteins in individuals. A track dug in an article of the magazine Nature, with evidence despite the small sample of individuals tested. It should also be remembered that it is due to a rare polymorphism in the CCR5 protein that some people are immune to the AIDS virus.
Particular cases therefore, which still need to be supported by science, but which in no way allow generalization. “There is no identified genetic group of people of whom we do not know if they will ever be infected, summarizes Bruno Lina. And since we are not able to identify a marker that immunizes, this means that everyone can be infected.”
The fact remains that international researchers are still looking for individuals who have escaped the virus to try to understand in detail their resistance, if it is proven. In the meantime, in the absence of robust data, Bruno Lina notes that we are currently only relying on feelings and intuitions to explain the fact of never having contracted the virus.
And the member of the scientific council added that since the beginning of 2022, “many individuals who had escaped the virus until then no longer escape it”, the fact, according to him, of a certain relaxation of measures. related in particular to a generalized “weariness” with respect to protective measures. “However, collective protection is the sum of individual protections. So if the general context is slack, some people can be caught up…”
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