Immunologist Kryuchkov called a new strain of coronavirus even more infectious

by time news

But at the same time, the mutant may be less pathogenic.

The Indian delta strain of the coronavirus gave “offspring”: its mutation was found in Britain – the AY.4.2 strain, which turned out to be 10-15 percent more infectious than its progenitor. A day later, this strain was already identified in Israel, in an 11-year-old boy. We talked with the immunologist Nikolai Kryuchkov about how the new version of the coronavirus will spread further, whether it will become more or less pathogenic compared to the “delta”.

The fact that the strain was discovered in the UK, where, according to the Financial Times, every tenth coronavirus patient is now infected with it, does not mean that it appeared in Foggy Albion. It’s just in Britain that the most massive studies of the biomaterial of patients are carried out. In particular, the strain was recently reported by Jeffrey Barrett from the Senger Institute in Cambridge and François Ballou from University College London.

In general, recently AY.4.2 has already been discovered in other European countries and in Israel. There, a teenager who returned from Moldova was hospitalized the other day with him. The boy was immediately quarantined to prevent the spread of the new strain.

Genetic modification of the “delta” is associated with the natural process of evolution of the virus, which should capture more and more “victims”, dodging their immunity.

“His appearance was expected,” says Nikolai Kryuchkov. – We see that AY.4.2 is 15% more contagious (infectious) than the “delta” itself. However, one must understand that this is several times less than the difference that the delta had in comparison with the post-Wuhan version. There can be no radical leap in this strain in terms of infectivity and ability to evade the immune response. The virus has an evolutionary limit – it cannot increase its infectivity indefinitely.

New strains, according to Kryuchkov, will definitely appear in the future. If the first Wuhan had an index of contagiousness (this property of infectious diseases transmitted from sick people to healthy people) from 2 to 6, the current delta strain has an index of 8, then it is possible that in the future humanity will “select” the maximum strains of SARS-CoV-2, bringing their contagiousness up to 10-11. This means that if today one person manages to infect up to 8 people, then in the future he will spread the disease to 10-11 “lucky ones”. And this, most likely, will be its limit.

– Will the new strain take the place of the delta strain?

– “Delta” took the place of the previous strain, because it was significantly, 2.5 times more infectious. The new one with “delta” has a difference of only 10-15%. The smaller this difference, the more difficult it is for a new strain to take the place of the previous one. Therefore, there is no reason for a sharp increase in infectivity. It will be very small or not at all. But the adaptation to vaccines will appear in the new strain, that is, the vaccinated will be infected with it in the same way as the unvaccinated.

But overall, the virus has fewer and fewer reserves. With an increase in infectiousness, its pathogenicity may weaken, it will get worse and worse by bypassing the immune system, taking into account the changes it becomes more and more difficult for it to cling to the receptors of the cell.

– When will the limit of variability of the virus come?

– The virus is constantly adapting to the human environment, like a person to the virus due to immunity. After a certain time, the virus should become milder for the population, and subsequently our immunity will still win it. After all, each time, changes occur in important areas, with which it binds to human cells. If we compare them with a key, it changes all the time, but the lock (our cell) remains unchanged. It turns out that the further you go, the less and less the key will fit the lock.

So, despite the fact that AY.4.2 is now the most infectious coronavirus of the entire pandemic, this does not mean that it will dominate the human population. Most of the new cases of COVID-19 are still associated with the Indian delta strain.

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