The scientific director of the Research Institute of La Paz University Hospital (IDIPAZ), in Madrid, got up last week with his partner with symptoms of a respiratory infection.As the protocol and common sense marks, Eduardo López-Collazof cases, the COVID-19.

The anecdote would have nothing particular but because López-Collazto the disease caused by the Coronavirus Sars COV-2.

This researcher is aware of two aspects that most people ignore: the first, which when vaccinating generated neutralizing antibodies against the protein s of the virus, which for practical purposes implies that their vaccine worked...It is not known for how long.

Fast and effective soldiers

The second, that its immune system is reprogrammed so that, if the virus tries to enter its organism, it deploys a whole series of weapons of mass destruction that prevents it from infecting its cells.We talk about T cells, fast and effective soldiers that can go to the battlefield or not.

It is impossible to quantify how many people have developed this cellular immunity in Spain or in the world.It can be calculated that a broad percentage of the vaccinated and practically all those who suffered the disease, but there is no way to quantify it with certainty.

We talk about cellular immunity, the parameter that can most indicate to what extent we are immune to COVID-19.The big problem?It is not an easy task.

We enter the laboratory directed.

On a computer screen, the researcher points to circular figures - which turns out to be cells - surrounded by a series of blue dots."Do you see?", Another researcher tells us at the controls of the PC, "these dots are cells of the immune system that have proliferated by contacting the cells-which turn out to be those of López-Collaz."They are like weapons of mass destruction," adds the owner of the cells portrayed.

"If there is no activation, we have not been in contact with the virus or have not been vaccinated.They are only in blood when there has been infection and/or vaccination, "explains the Spanish professor and immunology professor at the University of Valladolid Alfredo Corell on the phone..

"The Pepti...What? "Asks the journalist.But the name doesn't matter.In this case, it is only one of the commercial brands of what is used to demonstrate if there is cell immunity."It is a kind of conglomerate of particles that belong to the virus, we do not use the real virus or one attenuated, this is used," they clarify us.

While knowing if one has developed neutralizing antibodies to put on the vaccine or having suffered the COVID-19-is relatively simple and not too expensive-around 50 euros in private laboratories-in Spain, knowing if the desired cell immunity is possessed isAnother song: only a few - most researchers or participants in different studies - can know.

Natividad, 69, retired official, would love to be in the club of the IDPAZ scientific director.Today - and it is not ashamed to say it - it is still afraid of the coronavirus, a disease that has not passed, in front of the one that is vaccinated but that continues to disturb him.As it shows, more than one button: it is well that he got back to a bus, dared to go to the movies for the first time "and with fear" this week and, although resigned to the winter that arrives, he would prefer to continue always staying withYour friends on terraces.The same friends who did not see from March 2020 to June 2021, months after having vaccinated.

Day without sleep

"You have found the perfect person," jokes Nati, as they prefer to call her.Remember as if it were yesterday how her daughter called her and her husband in March last year to return from her town in Guadalajara, where they have a house, to return to Madrid because they were going to close it.Relive how those days was "without sleep" for the concern and how it took two months to step on the street and, when he did, he undressed as soon as he returned home and hung the clothes on the terrace.

Although he acknowledges being "quieter" now, Nati's bag does not differ in much from the one he had before vaccinating.There is still antiseptic gel and two types of masks: surgical and FFP2.The first is put to walk down the street, the second, for any store or enclosure closed.

When he has taken something inside a bar -scarcely -he has done it "very fast" and, although accustomed to being called exaggerated and tell him things like "if you have to infect, you will infect the same,"is resigned to this feeling."I am like that, what am I going to do".

So yes, Nati would like there to be a test to tell you if he is free of Covid-19 risk."Of course I would like it to exist.What is, like a blood analysis? "Asks.But it is very difficult, practically impossible, that Nati will know if he has cell immunity against the coronavirus Sars COV-2 although, according to the majority of experts consulted for this report, it would not make sense that he knew it.

The head of the Immunology Service of the Clinic Hospital of Barcelona, Manel Juan, is even somewhat irritated when asked about the possibility of making massive cell immunity tests to the population."Epidemiologically makes no sense, perhaps if there had been no vaccines, to manage your shortage," he reflects.

Juan, like López-Collazo and Corell, believe that everyone's current concern would have to go in one direction: that people who have not vaccinated."The most important thing is that in your environment there is no virus and this is achieved by making those who do not want to vaccinate themselves," he says.

The director of human genetics laboratories and infectious diseases ST.Giles (New York) and Necker (Paris), Jean -Laurent Casanova, recentTests to locate neutralizing antibodies-, which is already available ".

Manel Juan is the coordinator of a project funded by the company Cellnex Telecom that promotes research on cellular immunotherapies to deal with COVID-19.With this financing they have developed a test that measures cell immunity in much less time than other systems, just a few hours.

Like the rest of the experts consulted, it emphasizes that beyond the price of the test -which in its case has quantified in about 150 euros -, these tests are not designed to give people peace of mind, but for specific cases of patients in whichIt is suspected that the vaccine may not have worked."I speak of people like Colin Powell, who died of Covid-19 despite being vaccinated; surely he will have measured cell immunity," reflects the specialist.

Beyond the argument -coincident among experts -that it is difficultDo not worry about immune status after vaccinating: experience."We can give it many laps, but what we see after almost two years is that when you have contact with the virus you are immunized," he emphasizes.

Another argument that experts handle not to recommend the tests of neutralizing antibodies or those of cellular immunity-in the case that they could be generalized-is that immunity to COVID-19 will never be complete.In what sense?In which the immune person does not ill, but can always transmit the infection.

Neutralizing antibodies

Although the majority of researchers consulted for this report suggest that it is not necessary or advisable to worry about individual immune status, the reality is that there are people like Nati- and many more- who would like to know if they are immune to the covid-19.

And the market has an answer for it.If you look for Google the phrase "Test to know if the vaccine has worked" several affordable test options will come out that promise to answer that question.

However, they have a trick for those who do not know about the subject, since this type of tests only measure the presence of neutralizing antibodies, which gives an unpleth photo of the immune status in front of the coronavirus.

Corell, who is not in favor of the massive realization of this type of tests, denounces: "They have made very misleading and very aggressive advertising, with slogans such as 'we check if the vaccine has been done well.'.This should not be allowed, "he says.

The immunologist wonders why we do not care about getting antibody tests when we wear other more common vaccines, such as flu or measles, something that López-Collazo coincides, which adventures: "Many will not have developed antibodies".

On the other face of La Moneda, Larraitz Añorga, CEO of Biolan Health, one of the companies that make up the Spanish Bioepprier Association (ASEBIO) and manufacturer of one of those tests that measure the presence of neutralizing antibodies.Its price: 7 euros, although they are sold in packs of 20 and only health professionals.

In search of tranquility

Añorga does not discuss the thesis of the scientists interviewed for this report.He is aware that having these antibodies is not synonymous with being protected 100% of the COVID-19.But she makes them regularly - in the context of a clinical study - and also her parents."You can be a little calmer," he emphasizes.

"My mother had vaccinated a messenger RNA vaccine; my father with one of Adenovirus; she had neutralizing antibodies and he didn't.I repeated the test when a few weeks had passed since the inoculation of the second dose, in it, still had no trace, "he says.

Does this mean that the father of the CEO of Biolan Health is not protected in front of the COVID-19, which will take the disease if it is in contact with the virus, either because the incidence rises or because a child is yet yet vaccinated?The answer is "it is not known".To know, you would have to measure your cellular immunity, as López-Collazo has done."If the test gives negative, you will be doubtful if you have developed cell immunity but, if it is positive..."Añorga says.

Ask.- And he is different from his father than his mother?

Response.- The truth is, no.At first I didn't want to go home with my children, who are young and not vaccinated.I told my father that we were waiting for four weeks to spend the second dose, but I still didn't have antibodies.In the end, they told me that they could not live like this, that they assumed the risk.

And what about the duration of antibodies?It is known - and there is no doubt regarding this - that neutralizing antibodies have a certain duration.What is supposed - and we talk about assumptions because we talk about science - is that cell immunity compensates for that limited duration of neutralizing antibodies, which are measured with the most affordable tests.

Possibility of transmitting

Beyond the low availability of cell immunity tests and relevance or not to measure neutralizing antibodies, the current reality of the virus and the disease conditions any decision in this regard."That someone is protected does not mean that they are not susceptible to infecting themselves to some extent and could also lead him to think that they can travel without so much problem, embrace without problem...", reflects the professor of the University of Valladolid.Larraitz Añorga herself, who defends - as is logical - her antibody test, makes it very clear: "We do not recommend risk behaviors".

López-Collazo points out that vaccines currently approved "are not sterilizing, which implies that we do not have a total blockade in front of the virus".

And here is one of the reasons why this expert, lucky knowledgeable of his immune status, that Covid test was done when last week he had symptoms of respiratory infection.The other?Responsibility, underlines.

The unknowns that remain

Although it seems that much longer has passed, we have been knowing Sars COV-2 less than two years and the disease it causes.This implies that knowledge around this virus can change and that, without a doubt, it will be expanded.

At the moment, and speaking only of neutralizing antibodies - the ones that can be measured more easily - not only its duration is not known, or if it varies with the different vaccines, but it is not established which number of them are sufficient to guarantee a certainprotection.In fact, as Añorga explains, WHO is working on that idea and getting all kits to measure with the same scale.

Regarding cellular immunity, although scientific evidence seems to indicate that it is much more durable, it cannot be affirmed with a roundness.It will know when the time passes enough.

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