Where does the Omicron variant come from? | Science and Ecology | DW

Despite the scant data on the new strain of Omicron coronavirus, one thing is clear: it is dangerous! Due to the fifty mutations in the spike protein, it is not easily recognized by existing vaccines and largely escapes the immune response. That is, people who have been vaccinated can become infected with this type. It is also more contagious, so it can overwhelm health systems more quickly. There has already been a deceased person from this new variant and there are seriously ill patients in the hospital. This is why vaccination is so important.

appeared in parallel with other variants

The sudden appearance of the highly infectious omicron variant is interesting to science, not only because it evolved from other variants, but because it apparently appeared before or in parallel with alpha, beta, gamma and delta.

Dr Emma Hodcroft, a virologist at the University of Bern, says that because Omicron is so different from other strains, the closest “closest” to the virus is “difficult to identify”.

The omicron family tree in the Nextstrain database, where researchers from around the world save their results on virus sequences, clearly shows that this parallel evolution could have begun in mid-2020. With the data in mind, researchers have mixed three theories about the origin of this strain new.

In Britain, omicron quickly spread throughout the country, especially in the capital.

Theory one: unnoticed in an isolated community

The variant could have evolved in an isolated population, where the virus could have circulated for a long time with many infected and recovered people, without being able to record through testing and sequencing.

Christian Drosten, head of the department of virology at the Berlin Charité, supports this theory, he told the magazine Science Magazine: “I think it wasn’t developed in South Africa, where a lot of sequencing is currently done, but somewhere in South Africa during the winter spell.”

But Andrew Rambo of the University of Edinburgh does not find this theory very compelling. You cannot imagine how the virus can remain hidden in a group of people for so long. “I’m not sure if there is really any place in the world that is so isolated that this type of virus can be transmitted for a long period of time without appearing in different places.”

Second theory: Omicron could have evolved in an immunosuppressed patient

It likely comes from a person whose immune response has been affected by another disease or medication. These can be cancer patients or HIV patients, for example, because in immunosuppressed people, the body fights the virus for a longer time. This in turn has more time to develop mutations in order to avoid the immune response.

Proponents of this theory, such as Richard Lessels of the University of KwaZulu-Natal, refer in this context to a young South African woman with untreated HIV, who has been a carrier of the new coronavirus for more than six months. In her case and in other patients whose infection persisted for weeks or months, the same mutations that were also found in the worrisome variants were seen.

However, Christian Drosten, considering all the experiences with influenza and other viruses in immunosuppressed patients, ignores this theory: Although these people develop variants that escape the immune system, they are accompanied by a series of other changes that Affect their ability to broadcast, and omicron is definitely more contagious than the other variants.

The third theory: It evolved into an animal and jumped into a human

The virus could also be hiding in an animal, then evolved there, and then, through contact with humans, transformed into an omicron, the mutant strain. This theory is advocated by Christian Andersen, an infectious disease researcher at The Scripps Research Institute, Calif., or evolutionary biologist Mike Warob, of the University of Arizona, in Tucson.

This theory is supported by the fact that some animals have also been shown to be infected with SARS CoV-2.

This is also why most researchers also assume that the original type of SARS-CoV-2, which first emerged two years ago in Wuhan, China, was of animal origin.

As further evidence, proponents of this theory cite that the virus in the animal was subjected to completely different evolutionary stresses, which could explain the number of new and sometimes unique mutations such as the omicron.

(rmr/ms)

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