This article is excerpted from "Reading" #456 newsstand from Sunday 23 August (and throughout the week) in combination with the "corriere della Sera" and available in the App of "Reading" for smartphones and tablets.
about Covid-19 has been spoken about so much and you continue to talk about the asymptomatic — and also with a certain amount of apprehension — because they seemed to be the ones who spread the disease among each other without knowing it. And if they were right their to help us come to grips with the pandemic of Sars-CoV-2?
Begin doing so in many and, paradoxically, the idea comes from a... a prison; or, better, by what is happening in some prisons in the United States. According to the "Washington Post" in Arkansas, North Carolina, Ohio and Virginia infected persons among the detained are more than three thousand: well, the 96 percent of them have no symptoms. It is one of the mysteries of this virus that we begin to know a little bit, but not quite yet. Why, for example, there are people who live or work in contact of anyone who is sick, it will infect, but do not have symptoms and are not sick? If we could figure out what it is that protects them, we could certainly have one more weapon against this virus.
Monica Gandhi, an expert in infectious diseases at the University of San Francisco in California, he immediately wondered why there was such a large number of infections asymptomatic. This is his conclusion: "it is Not said that it is always a problem, far from it; might be good for the individual and for society".
Maybe yes. To be able to prove that the doctor has collected all the information possible about the asymptomatic, starting from the data of the Centre for the Control and Prevention of Diseases in Atlanta. They had already seen that the 40 percent of the people infected have no symptoms, perhaps because of the masks. But there could be other reasons: the conformation of the receptor that the virus uses to enter cells, for example, or a genetic structure which is particularly favourable. Or perhaps the experts might be wrong: "Sars-CoV-2 — repeated — is a virus and our immune system was caught off guard; we don't have weapons to defend ourselves".
But this may not be true; more and more jobs — all very recent — they advance the hypothesis that a significant part of the population has already been exposed in the past to something that looked like Sars - CoV-2 even before the virus was discovered. If so, that would mean that among us there are people who, without being sick nor vaccinated, are already immune to them, at least a little.
it must Be said that our immune system is a formidable machine for the memories, he is able to recognize all that he has seen in the past; not only that, but each new encounter its memory is strengthened and expands. And this is all thanks to a certain cell that immunologists call memory T cells would be lymphocytes of the memory) who travel tirelessly in our the bloodstream to defend ourselves from invaders and in the specific case, may remember to have seen in the past something very similar to Sars-CoV-2. For example, the coronaviruses of common colds, which they share with the virus Covid-19 certain proteins not identical but very similar, as it shows a beautiful work just published on "Science".
But can not even exclude that they are the proteins associated with childhood vaccinations that induce the formation of memory T cells which then recognize Sars-CoV-2 as something familiar.
Francis Collins, the director of the National Institutes of Health, is convinced of it, so as to have published a post in these days to support the role of T lymphocytes of the memory in the protect you from getting sick so many that have been infected by the virus.
The rest is as you would explain otherwise the fact that in Sweden — that did not lockdown — the number of sick people decreases? Should be tied to a immunity pre-existing . And it is so in other areas of the world, even the very poor, where the quarantine is simply not the you could do. Serological tests that measure antibodies against the Sars-CoV-2 tell us that those who have encountered the virus are many more than we thought, but maybe there are even more of those that would have already been immune thanks to the cells of the memory.
opens in short, a field entirely unexplored, but perhaps more important than the one on which we have focused so far.
"we are waiting for confirmation," says the immunologist american Anthony Fauci, "but it is possible that it is so and it would be really good news". Mouth — that he never spared criticism of the management of the health crisis on the part of the administration of Donald Trump — think more about the role of viral load to explain why someone becomes seriously ill while the other, despite attending the same environments, have little or nothing.
you Must also consider that the antibodies go away soon, while the cellular immunity is long, even if it is more difficult to study. They have done the researchers of San Diego, California, on old blood samples from donors, and have found that in 40-60% of those samples were found T cells capable of recognizing the Sars-CoV-2. The virus then there was still, to which you will have to think of a sort of immunity pre-existing.
The confirmation comes from studies with very similar facts in Holland, Germany and Singapore the results are absolutely the same.
There is another aspect Covid-19, which deserves great attention: that of the children. They have more virus in the nose and throat of adults, but is rarely sick and has not yet figured out if they can infect.
How do you explain that?
May have memory cells also vaccinations are recent. For this reason, Andrew Badley and colleagues at the Mayo Clinic have addressed the problem systematically to find out that, if in the previous five years you have been vaccinated, you have some form of immunity against Sars-CoV-2, and this is true for at least seven vaccines, but especially for those against pneumococcus (which reduces the risk of developing Covid-19 of 28 percent), and against polio (which reduces to 43 percent).
Change the paradigm in short: from now on, instead of looking at asymptomatic as the people who spread the disease, we can look with gratitude. Who knows, maybe one day are not their own to liberate us from Covid-19 through a immunity of the population is made also by all those who have the antibodies but maybe even more by those who have the cells of the memory specific, which would limit greatly the spread of the virus even in areas where the positive does not exceed 10-20 percent of the population.