Omicron is no longer a “variant of concern”.

Dhe European epidemic center ECDC has downgraded the threat potential of the long-dominant Sars-CoV-2 variant Omicron: from a potentially dangerous “variant of concern” to a “variant of interest”. This is the second highest of three World Health Organization categories. This means that there are currently no longer any coronavirus variants with the highest threat level. “This reflects the currently stable epidemiological situation in Europe,” says an ECDC statement. At the same time, the authority warns: “However, this does not mean the end of the threat from Sars-CoV-2 and its possible future variants.”

Joachim Müller-Jung

Editor in the feuilleton, responsible for the “Nature and Science” department.

Omicron was first discovered in southern Africa in November 2021 and attracted attention with a particularly large number of new mutations. The original virological designation was B.1.1529. It quickly became apparent that it was not only easier to transmit than earlier variants, but that it also had special immune escape properties due to the composition of the mutations on the virus surface – that these mutations also spread among partially and fully vaccinated or earlier people infected populations (however, with existing immunity, still rarely caused severe disease progression).

Virologists speak of “variant soup”

When the World Health Organization included the variant under the name Omicron in the highest level of danger a year ago, the virus had already arrived on practically every continent. It quickly replaced the variants that had prevailed in many places, such as Delta, as the dominant pathogen variant. At the same time, new mutations emerged and omicron subvariants such as BA.1, BA.2, BA.3, BA.4, BA.5 evolved, spreading at different rates in different parts of the world.

The mass spread of omicrons has recently increased the number and combination of mutations enormously. In addition, there have also been many mixtures of different Sars-Cov-2 subvariants – recombinants – such as XBB.1.5, which are now successively replacing the BA.2 or BA.5 or BQ.1, which have also been dominant in Europe for a long time. Apparently, these new evolutionary stages of the virus have a transmission advantage – albeit a slight one – over the older variants.

In the meantime, in the words of many virologists, a “soup of variants” has formed from numerous development stages of the pathogen that are spreading side by side. In fact, the recombinants XBB.1.5 and its “cousin” XBB.1.9.1 have taken over the scepter worldwide.

All currently circulating variants are no longer classified as worrying in terms of a pandemic threat, at least in Europe. However, this is not because the new variants are harmless, because they can also trigger severe Covid 19 courses in vulnerable, immunosuppressed patients. This has been shown again and again by waves of infection in immunologically “naïve” population groups or in vulnerable people. In fact, Omicron is considered less dangerous epidemiologically because the immunity situation now protects the broad mass of the population quite well. The protection built up through immunization, primarily through T cells and long-lived immune memory cells, prevents severe or even fatal Covid 19 disease progression in most cases.

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