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Precursors of the recently discovered corona variant Omicron are likely to have existed for a very long time, according to their co-discoverer. “According to current knowledge, an early form of Omicron evolved as a separate virus type even before Alpha and Delta emerged,” Wolfgang Preiser of Stellenbosch University near Cape Town told Deutsche Presse-Agentur. He is a member of the research consortium that discovered the variant.
This type of virus then probably evolved over many months without attracting attention, the German said. “The question is: Why did Omicron remain hidden for so long and only now get going? Were there still one or two mutations missing to be able to spread quickly?” The oldest known detections of the variant so far date from the first half of November.
Especially many mutations
The variant, first discovered in South Africa and Botswana, has a particularly large number of mutations. Among other things, they affect the spike protein, which the viruses use to dock with human cells. In addition, there are mutations near the so-called furin cleavage site, a region that plays a role in the uptake of the virus into human cells.
Omicron could be the dominant variant in Europe in as little as a few months, according to the EU health agency ECDC. The agency recently pointed out that while there remain a number of uncertainties regarding transmissibility, severity of disease and possible effects on immune defenses, the virus is not yet known to be present in humans. However, preliminary data indicated that Omicron had a clear advantage over the Delta variant. The WHO classifies omicron as a “concern.”
More easily transmissible
Preiser assumes that Omicron is more easily transmissible than Delta. He does not see definitive evidence that Omicron tends to lead to milder disease courses. It is still too early for that, he says. It’s also unclear whether children are particularly susceptible to omicron, he said. “Although there are many hospitalizations among children in South Africa right now, they are also virtually unvaccinated,” Preiser said.
There are several theories on the origin of omicron, Preiser said. For example, it could be that the corona variant developed in a patient with HIV or another form of immunodeficiency. The idea: In people with weakened immune systems, the virus could replicate and change bit by bit over many months without being eliminated entirely by the immune system. “This is a speculative hypothesis and not proven,” Preiser said. Another hypothesis is that omicron evolved in animals.
Other questions also remain unanswered, such as how vaccinations against omicron work. “It is true that there are currently a lot of breakthrough infections in South Africa in those vaccinated with omicron. But it’s unclear whether that’s due to specific characteristics of the variant.” It is also conceivable that external circumstances play a role, he said. For example, health care workers are currently frequently infected, and they are more affected by a decline in protection, in part because of early vaccination.
- source: kurier.at/picture: pixabay.com
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