New study
Why the rapid spread of Omikron could be a reason for (cautious) optimism
An infection with the coronavirus can severely damage the lungs.
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Omikron is spreading extremely quickly and could soon replace Delta as the predominant Corona variant. New study results on the course of the disease show why this may even be good news.
The Omikron infection numbers continue to rise tirelessly. In the meantime, 30,325 cases have been assigned to the new Corona variant (as of 3.1.), And the trend is rising. Experts agree that it will soon replace Delta as the predominant variant. In Denmark, for example, this has long been the case. And that could be good news. Because although the peak of the current wave in Germany has not yet been reached, experts are already cautiously optimistic. And Health Minister Karl Lauterbach even spoke of a “light at the end of the tunnel” on the ZDF New Year’s Eve show.
Finally, there is increasing evidence that Omikron spreads much faster than Delta, but also causes less severe cases. An explanation of why this is so is provided by the study by a research team from the USA and Japan, which has so far only been published as a preprint. According to this, the solution to the riddle could be found in the lungs.
Mild courses after an Omicron infection
For the study, the scientists infected mice and hamsters with different variants of the coronavirus. They found that the animals that had been infected with Omikron had milder symptoms on average, lost less weight and died less often than the comparison animals.
The golden hamsters caused a surprise. Corona infection has almost always been difficult in experimental animals of this type. On the other hand, they coped with the omicron infection comparatively well; only mild courses were observed. Michael Diamond of Washington University in St. Louis and co-author of the study emphasized to the “New York Times” (NYT): “That was surprising, since every other variant has strongly infected the hamsters.”
How can that be? The experts could have found an answer in the animals’ noses and lungs. Because Omikron seems to focus more on the upper respiratory tract than previous variants. The measured viral load in the noses of the hamsters was just as high as in animals infected with other corona variants. On the other hand, the scientists were able to detect much less virus in the lungs – only about a tenth of the amount compared to other variants. Less damage to the lungs was also observed in this context. It should be noted with these results that the study has not yet been reviewed by independent experts. It is also a study on animals, not humans.
A research group from the University of Hong Kong had also already presented study results in mid-December, according to which Omikron probably also spreads more slowly in human lung tissue than other corona variants – according to the results up to ten times more slowly. However, with twelve tissue samples taken, it was a very small test. Further studies are needed to solidify the data.
Does Omikron have less cell grip?
Coronaviruses usually spread from the upper respiratory tract, through the mouth, into the throat and into the lungs. An infection usually only becomes dangerous when the virus makes it into the lungs, which can lead to severe inflammatory reactions and damage, including acute lung failure.
It is still unclear why the lungs are largely spared from the omicron variant. But there are already the first theses. The answer could be found in the TMPRSS2 protein. This can be found on the surface of many lung cells. Scientists working with Ranvindra Gupta, a virologist at the University of Cambridge, had found in a laboratory study – also with animals – that the Delta variant was very good at infecting such lung cells, but Omikron was not.
According to this, the omicron may not adhere as well to these cells. A result that a research group from the University of Glasgow came to independently of Gupta’s team. Another indication could be that the protein is almost impossible to find in the cells of the upper respiratory tract, i.e. where the omicron spreads very easily. Here, too, further studies are necessary to provide valid statements.
Beware of too much euphoria
All these hints are still no reason to fall into euphoria. Even in the best-case scenario, the coming weeks will be a challenge – due to the sheer number of infections to be expected and the comparatively large vaccination gap in the country. It is to be feared that there will be “a further increase in serious illnesses and deaths” in Germany, estimates the Robert Koch Institute (RKI) in its current risk assessment.
This assessment is supported by recent figures from the USA and Great Britain, where many hospitalizations are currently facing a shortage of staff. “Perhaps everyone who promoted ‘Omicron is mild’ and ‘no need to worry’ should be fired,” tweeted US epidemiologist Eric Feigl-Ding on Monday in relation to the developments. It was a situation that will repeat itself worldwide if Omikron is not stopped.
The RKI recommends that it is therefore important to sustainably reduce the number of infections, for example by reducing contacts and adhering to the tried and tested distance rules. Further building blocks are closing the vaccination gap and booster vaccinations. Almost everyone who is currently infected with Omikron – around 98.5 percent – are unvaccinated.