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Coronavirus: What is Known About the Origin of Omikron

2021-12-04T11:09:54.173Z

There is a clear gap in the family tree of Omikron. Experts are trying to find out when the new variant of the coronavirus could have emerged - and have a first clue.



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Hong Kong: Omikron has already arrived here too

Photo: Li Zhihua / China News Service / Getty Images

According to experts, forerunners of the recently discovered Omikron corona variant could have existed for a very long time.

Omikron itself has probably also been spreading for a few weeks and initially went unnoticed.

According to the current state of knowledge, an early form of Omikron developed as its own virus type even before the emergence of alpha and delta, "said Wolfgang Preiser from Stellenbosch University near Cape Town to the dpa news agency.

He is a member of the research consortium that discovered the variant.

The first evidence of alpha and delta comes from the fourth quarter of 2020. The next known evolutionary link from Omikron, on the other hand, is to virus variants that were already detected in mid-2020.

This is shown by data from the Nextstrain database, into which experts all over the world feed their sequencing results (read more here).

How the early Omikron relatives became the variant that is now in focus is a mystery to experts.

The virus line apparently evolved over many months without attracting attention, said Preiser.

“The question is: Why did Omikron stay hidden for so long and only start now?

Are there still one or two mutations missing to be able to spread quickly? "

First appearance in early October?

Omikron was detected for the first time during routine sequencing in the first half of November 2021 in the South African province of Gauteng and in neighboring Botswana.

77 cases were discovered in South Africa.

Subsequent examinations showed the virus type there also in samples from November 8th.

The virus probably circulated even earlier.

Trevor Bedford, who researches the evolution of viruses at the University of Washington and is involved in Nextstrain, estimates based on the omicron sequences known from around the world as of Wednesday that the variant emerged from its closest relative on September 30th.

Accordingly, the new virus type could spread since the beginning of October.

"Omikron appears to have first appeared around October 1st and it took eight weeks of exponential growth to" suddenly "have a significant impact on the number of cases and hospital stays in Gauteng," Bedford writes on Twitter.

However, the information should still be viewed with caution.

According to statistical analyzes, there is a high probability that Omikron could have appeared for the first time on September 9th or October 13th.

Accordingly, the variant could have spread much longer or much shorter before it was discovered in mid-November.

Several theses on the history of its origins

What is striking about Omikron is the very high number of mutations at critical points.

Among other things, they affect the spike protein, which the viruses use to dock onto human cells.

There are also mutations near the so-called furin binding site, a region that plays a role in the uptake of the virus in human cells.

It is being discussed whether the corona variant could have developed in a patient with untreated HIV or some other form of immunodeficiency.

The idea behind it: In people with a weakened immune system, the coronavirus can multiply over a long period of time and change bit by bit without it being completely switched off by the immune system.

This could explain the large number of mutations.

But that is not proof.

"That is a speculative thesis and not proven," says Preiser.

Another hypothesis is that the omicron evolved in animals.

Spread worldwide

In Germany, according to the Robert Koch Institute (RKI), four cases of Omikron had been confirmed by genome sequencing by Wednesday - all of them concerned people returning from South Africa.

In eight other cases there is a suspicion of the variant.

Experts assume that the new virus type will also appear in Germany.

"Infections from the South African epidemic are now being detected around the world, and these exports are triggering local transmission," said Bedford.

He also showed a screenshot of the Nextstrain database, which shows the regions of the world in which Omikron has been discovered so far.

In addition to Europe, the virus line was detected in Australia, Brazil, Great Britain, Hong Kong, Israel, Japan, Nigeria, Norway, Sweden and the USA, among others, until Saturday.

Most of the people affected there were also travelers from South Africa - but not always.

It is quite possible that the virus line is already circulating there undetected.

The EU health authority ECDC fears that Omikron could be the dominant variant in Europe in just a few months.

"On the basis of mathematical models from the ECDC, there are indications that Omicron could cause more than half of all SARS-CoV-2 infections in the EU / EEA within the next few months," wrote experts in a statement on Thursday.

The delta variant is currently dominating the infection rate in Europe and many countries around the world.

There are still a number of uncertainties regarding the transferability, the severity of diseases and possible effects on the immune system, the authority continues.

However, preliminary data indicated that Omikron had a clear advantage over the Delta variant.

Preiser also fears that Omikron could be more easily transferable than Delta.

The World Health Organization (WHO) has classified Omikron as "worrying" due to the many mutations in critical areas and the information known so far.

In addition to the virus line, beta, gamma and delta are on the list of "worrying variants".

However, beta and gamma have so far not been able to prevail against Delta because they are less contagious.

Many more unknowns

Many questions also remain unanswered in other areas.

Preiser sees no definite signs that Omikron leads to milder disease courses.

It's still too early for that (read more here).

It is also unclear whether children are particularly susceptible to Omikron.

"Although there are currently a lot of hospitalizations among children in South Africa, they are hardly vaccinated," said Preiser.

It remains to be seen how reliable the Covid-19 vaccinations against Omikron will work.

“There are currently many infections in people vaccinated with Omikron in South Africa.

But it is unclear whether this is due to the variant's special properties, ”said Preiser.

It is also conceivable that external circumstances played a role.

Healthcare workers who, among other things, are more affected by declining protection because of an early vaccination, and at the same time often come into contact with the virus, are often infected.

At the same time, the omicron infections in vaccinated people are usually mild.

It is therefore conceivable that the vaccines will at least continue to provide good protection against severe courses.

With material from dpa

Source: spiegel

All tech articles on 2021-12-04

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