Omicron cases are reaching highs, but new data puts an end in sight

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Several new studies have confirmed the positive side of the Omicron variant: even if the number of cases rises to a record high, the number of severe cases and hospital admissions is not the case.
The data, some scientists say, point to a new and less worrisome chapter in the pandemic. . “Now we are in a completely different phase,” said Monica Gandhi, an immunologist at the University of California, San Francisco.

“The virus will always be with us, but I hope this variant induces enough immunity that the Omicron variant was discovered in South Africa just over a month ago, and experts warn that it will be a long time before the situation is changing, but Data from last week suggests that a combination of widespread immunity and numerous mutations resulted in a virus that causes much less severe disease than previous iterations.

A study conducted in South Africa found that patients admitted there during the fourth wave, which was dominated by the virus omicron, were 73% less likely to develop serious illness than those admitted during the third wave dominated by delta.
“The data is pretty strong now with hospitalizations and ‘uncoupled cases,” said Wendy Burgers, an immunologist at the University of Cape Town.
Initially, much of the concern about Omicron was due to the large number of mutations in the variant, many of which the Spike protein, the part of the protein that is found, not only easily infects unvaccinated people, but also prevents antibody responses from past infections and vaccines.
He made his way beyond these first lines of defense. Several factors appear to make the Omicron variant less virulent or less virulent more severe than previous Covid19 waves. The ability of the virus to infect the lungs. Covid infections usually start in the nose and spread to the throat.

A mild infection does not go beyond the upper respiratory tract, but when it does. When the virus reaches the lungs, it is usually the hardest and symptoms appear.

But five separate studies from last week suggested that the variant does not infect the lungs as easily as previous variants. In a study pre-printed online by a large consortium of Japanese and American scientists, omicron-infected hamsters and mice experienced very severe illness with previous iterations of the virus. took a small number of lung tissue samples from patients during surgery and found that Omicron grew more slowly than other variants in these samples.

Burgers said this change in virulence likely had to do with how the anatomy of the virus changed. Pathways into cells, and now he prefers one of those pathways because of all the changes in the spike protein, “he said.
It seems that it prefers to infect the upper respiratory tract rather than the lungs. This, Burgers said, could mean a less serious but also more transmissible infection, as the virus replicates more frequently in the upper respiratory tract, from where it can spread more easily. Second line of defense from previous vaccines and infections: cells and cells.

T cells are responsible for attacking a virus once it enters the cells of the body if the antibodies fail to prevent infection in the first place. In a recent study by Burgers and colleagues, scientists used white blood cells from Covid patients to show that around 70-80% of the T-cell response is conserved compared to earlier strains of the virus. That means for those who are vaccinated or have had a Covid infection in the past 6 months, their T cells are likely to be able to recognize omicron and fight it relatively quickly.

This latest research should be complemented with more studies. If it stands up to additional scrutiny, it could explain why current infections appear to be milder than previous waves of the virus.

“When you start looking at different kinds of data, all pointing in the same direction, you start to feel more confident that it will stick,” said Jessica Justman, an epidemiologist at Columbia University Medical Center.

However, as cases skyrocket, the absolute number of hospitalizations and deaths with them will continue to rise, even as those numbers rise more slowly.
“If your denominator is huge because a lot of people get infected, you still end up with a lot of people who go to the hospital and need care,” Justman said.

Gandhi, from the University of California, San Francisco, said that while the number of cases could break records, hope was expressed that the combination of highly transmissible omicron and a mild infection could indicate the onset of the disease in another study, held in Hong Kong last week. that vaccinated patients infected with Omicron also elicited strong immune responses to other versions of the virus.
This could explain why the number of cases in South Africa has rapidly peaked.
“I hope this variant creates deep immunity in the population.” Hopefully the pandemic ends. “

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