Delta variant: what it is and how do you get infected in the gym and at the stadium

Why is the Delta variant of Sars Cov-2 more contagious? Why are stadiums risky? Can we be safe in the gym? How should those who go to the pool or practice contact sports behave? We asked the professor Massimo Clementi, Full Professor of Microbiology and Virology, Vita-Salute San Raffaele University and director of the Microbiology and Virology Laboratory of the San Raffaele Hospital in Milan. Clementi, who recently published the book with his colleague with Giorgio Palù Virosphere. Journey into virology, the most fascinating biomedical discipline (La Nave di Teseo), also explains us why we have some reason to look to the future with relative optimism.

Covid, the Delta variant: what exactly is it and how did it spread? –

The Delta variant is one of 20 variants of the SARS-CoV-2 that have emerged in the past year. A variant emerges when the new virus confers an advantage on its spread. The delta variant is divided into 3 sub-variants, each of which has the characteristic of favoring contagion. Contagion that occurs when the virus finds no obstacles, that is, where there are subjects who are not vaccinated or only partially vaccinated. This is why there has been a significant spread in the United Kingdom: there they aimed the entire initial phase of the vaccination campaign to offer a single dose to the largest possible number of people. At first, this strategy gave a good result and the ongoing epidemic wave was stopped. But then some problems arose, due to the close relations between the UK and India, and this variant, which was widespread especially in New Delhi in January, quickly passed to Great Britain, where people vaccinated with only one dose proved susceptible to becoming infected.

Delta variant: what is the difference with the other variants of Covid? –

The Delta variant seems to infect young people with particular efficiency, also because they are the least vaccinated. The infection is generally not serious and affects the upper airways, pharynx and larynx, and not the bronchi and lungs, as the infections of the first epidemic waves. this means that – at this moment – it has less severe clinical features. The numbers say it: in the United Kingdom, in the face of 20,000 and passes infections a day, the number of hospitalized and dead has moved very little. But to keep the Delta variant and all the others at bay, those ways of life that can favor transmission must be avoided.

Can crowded European stadiums facilitate contagion? –

It is not just a question of stages. The matches of the Europeans favor travel, after a very long closure of the borders. And then there is the off-stage: when the fans, understandably, celebrate after the victory and do not care to respect the distance. Fortunately, our vaccines are able to fight the current variants. Anyone who has undergone complete vaccination is protected from the disease of all the variants that have occurred so far. This is certainly good news that should show us the way forward.

Covid: do we have any reason to be optimistic about the future? –

The fact that vaccines also protect against this variant is good news: it means that the virus cannot change too much. There is a limit to this variability. But it must be said that it is difficult for a virus that has come to man from the animal world to become worse than it was at the beginning. Almost always, in the adaptation phase, the virus adapts to the host and a better coexistence is achieved than that observed at the beginning of the epidemic. Then there is another aspect to consider: the variability on the basis of which we identify the variants, concerns the structure of the protein S (Spike) that is used by the virus to attach the cell that it will infect. This protein has a function: it must be such as to recognize the receptor present on the cell therefore it cannot change beyond measure, otherwise it would lose this function. This limits its possibilities.

Why do we need to get vaccinated if the virus seems to be in retreat? –

Consider that a virus – just one – infecting a cell can generate another 3000. Of these 3000 new viruses, 30 to 60 are variants that are lost because they do not confer any advantage. Only very few are the variants which, having a higher transmissibility, are able to prevail. By vaccinating ourselves we prevent the virus from infecting us and others and therefore from replicating, creating new variants. It also applies to young people: they are a population that can amplify this virus. If, on the other hand, we manage to block the circulation, we reach the so-called population immunity.

Delta variant and sport: is it dangerous to go to the gym? –

It is clear that an indoor facility has problems with the transmission of a respiratory virus. In the gym, people hyperventilate, so if a distance of 1.5 meters is enough outside, that’s not enough. And remember that Delta variant has two characteristics that make it different from the previous ones. First of all, as we have said, it infects more efficiently. Then, it is more present in the pharynx and upper respiratory tract, which means that the virus can be emitted more efficiently: transmission can occur even in a few seconds of contact than in the past. This is why in gyms, as never before, you have to guarantee efficient air exchange, there must be no crowds and you have to be careful to keep your distance.

What to do in case of contact sports? –

In contact sports, for example boxing, among people who have not been vaccinated in full cycle, the risk of infection is very high: in this case a tampon made in the hours before the meeting could be useful to rule out an ongoing infection. A molecular swab would be better, because the antigenic swab on average has a 20% less sensitivity. But in any case, the unsanitary is better than nothing.

And do we risk the same in the pool and on the beach? –

In an outdoor swimming pool the risk of becoming infected is low. Actually even indoors, if the water is chlorinated and we respect the spacing rules. On the beach, if it is crowded, you need to have some judgment, especially those who have not completed the vaccination cycle because the reduced distance favors the Delta variant. Those who have been vaccinated, on the other hand, can feel more comfortable, because it is good to repeat it, the vaccines we have to date have also proved effective against the Delta variant. The vaccine is really the only weapon we have.

06 July 2021 (change 06 July 2021 | 11:00)

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