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Why is Omicron less severe than Delta?

2 years ago babelfish

Why is Omicron less severe than Delta?

Omicron is more transmissible but less deadly. There are more and more studies to support this thesis. Here's what they say and when the pandemic will end

Evidence is mounting that Omicron, despite spreading at unprecedented speed (it has also reached Antarctica ), is less deadly than other Covid variants. According to the scientists, the reason would be that Omicron infects the throat more than the lungs, thus causing milder consequences.

WHAT THE STUDIES SHOW

Six recent studies, still pending peer-review, have shown that Omicron does not harm people's lungs as much as Delta and other variants.

“Basically,” Deenan Pillay, a professor of virology at University College London, told the Guardian , “it appears [Omicron, ed ] is more capable of infecting the upper respiratory tract – the throat cells. It would then multiply in the cells there more easily than in the deep lung cells. It is a preliminary result, but the studies point in the same direction ".

BECAUSE OMICRON IS LESS SEVERE

If the virus produces more cells in the throat, this makes it more transmissible, which would help explain Omicron's rapid spread. But a virus that manages to infect lung tissue is potentially more dangerous but less transmissible.

WHAT SILVESTRI THINKS

A study entitled "The SARS-CoV-2 B.1.1.529 Omicron virus causes attenuated infection and disease in mice and hamsters" conducted by an international team and also cited in a series of tweets by immunologist and virologist Guido Silvestri, professor in the United States at Emory University in Atlanta, according to the Italian expert, confirms the studies from Hong Kong and Belgium, and the clinical data from South Africa and the United Kingdom .

Already in recent weeks, Silvestri had invited people to "trust", despite "a growth in infections that looks like an avalanche" because the hope is "that the virus is cooling down" – but only for the vaccinated, he added.

“Anyone who does not vaccinate on the basis of his idea of ​​individual freedom – said Silvestri – makes others pay a high price and risks a lot himself. The No-vax are 80% of the hospitalized: reflect on this the millions of Italians who still refuse the vaccine ”.

THE POINTS IN COMMON BETWEEN THE STUDIES

A study conducted by the University of Liverpool shows that Omicron leads to a "less severe disease" in mice which, when infected with the variant, lose less weight, have a lower viral load, experience less severe pneumonia and recover faster. . However, this still does not mean that we can let our guard down because the most fragile people can run into a more serious form.

Another pre-print, presented to Nature last week by researchers in the United States – the Guardian writes – also confirmed that the mice with Omicron lost less weight and had a lower viral load, and researchers at the University of Glasgow have found. evidence showing that Omicron changed the way it enters the body.

DOUBT ABOUT PADS

If Omicron is confirmed to infect the throat more than the lungs, then nose swabs may not be the most reliable method, according to research from University College London. It would, in fact, be more useful if they were carried out in the throat.

Professor Jennifer Rohn, one of the authors of the study, told her personal experience on Twitter: after testing negative using a nasal swab, she carried out a second quick test by taking a sample from her throat which, instead, tested positive.

This, the Guardian said , is reflected in a South African study showing that saliva samples subjected to PCR tests are better than nasal swabs at detecting Omicron. However, some experts believe the study is too small to draw conclusions.

MOUNK'S FORECASTS

"There are two ways in which the pandemic could end in 2022," says political scientist Yascha Mounk in an interview with Corriere della Sera , who recently wrote an article for The Atlantic magazine entitled "Omicron marks the beginning of the end ".

The first way, explains Mounk, is biological: “discovering that Omicron does not make the clear majority of people seriously ill and that exposure to this variant, if vaccinated, protects against future strains; thus the objective threat of Covid would cease to be significant. But this is a conjecture. We do not know if this will be the case, even if it is a hope and a plausible scenario ".

The second way the pandemic could end, the political scientist continues, is social, "as I argue in the article, is to say that we have become accustomed to the fact that our lives will involve more risks in 2022 than in 2019, but collectively and individually we choose that living in a more normal way is worth taking those risks ”.

This is a machine translation from Italian language of a post published on Start Magazine at the URL https://www.startmag.it/sanita/perche-omicron-e-meno-grave-di-delta/ on Mon, 03 Jan 2022 13:25:47 +0000.