This is what is known about omicron, a very contagious version of COVID-19

Ómicron is a variant of COVID-19 detected about a month ago and due to its high degree of transmission, it can once again change the course of the pandemic, especially due to its impact on vaccination.

What is omicron?

Omicron It is a new version of SARS-CoV-2 (the coronavirus originating from the pandemic), identified at the end of November in Botswana, and then in South Africa.

Its peculiarity is the large number of mutations with respect to the original variant that was detected in the Chinese city of Wuhan, and of later versions, such as the delta, which until now largely dominates the transmission of the pandemic.

It is not known how it appeared omicron. One hypothesis under debate among scientists is that the virus would have slowly mutated in the body of a person with immunodeficiency, a process that lasted several months, until it reached the current version.

Why does it worry?

It is highly contagious, “at a rate that we have not known so far with any other variant,” warned Tedros Adhanom Ghebreyesus, director general of the World Health Organization (WHO).

This new version “is probably found in most countries,” he added. It has already been officially detected in at least 80.

South Africa, Denmark and the United Kingdom have already warned that cases are growing exponentially. Omicron it could be the dominant variant in Europe in mid-January, the president of the European Commission, Ursula von der Leyen, declared this week.

Will it definitely replace the delta variant? Scientists warn that the two could coexist, as happens with certain variants of the flu virus, or that omicron Gain ground and then give delta an advantage again.

What impact for vaccines?

Current vaccines are already losing their efficacy against delta. The mutations that the variant presents omicron they can greatly reduce the immunity of antibodies to the virus.

Consequently, it can probably re-infect people who were previously affected by the virus, and contaminate a significant number of already vaccinated people.

Several recent laboratory studies support the latter hypothesis. The antibody rate drops dramatically before omicron among those vaccinated with Pfizer / BioNTech, Moderna, and even more so with AstraZeneca or Sinovac.

At the moment, a booster dose of the vaccines helps to strengthen the defenses. And in any case, the drugs are still effective, even though the antibodies they generate are only part of the immune response.

“Cellular immunity,” which passes through cells called T lymphocytes, is much more difficult to detect.

A study published this week in South Africa suggests that the Pfizer / BioNTech vaccine is effective against severe forms of the pandemic caused by omicron, included after the first two doses.

Omicron it also apparently poses difficulties for synthetic antibody treatments, especially among already hospitalized patients.

Less dangerous?

The clinical data of the last weeks suggest that omicron it is no more dangerous than its predecessors, particularly delta. It is “almost a certainty,” US presidential adviser Anthony Fauci told AFP in early December.

The first death from omicron It occurred a week ago in the UK.

“We are concerned that people consider omicron as benign ”, warned the boss of the WHO. “Even if it causes less severe symptoms, the number of cases could once again flood unprepared health systems.”

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