It’s a déja vu: As in the initial phase of Delta, only a few cases of the Omikron variant have so far been confirmed. But the number is growing rapidly. Will Omikron soon determine the corona infection process? Is it going to get worse?
It is only since last Friday that it has been generally known worldwide that it exists – and international evidence of the Omicron variant (B.1.1.529) of the coronavirus is already increasing. The World Health Organization (WHO) quickly classified the abnormally large number of changes in the genetic make-up as “worrying”. But what is known about how dangerous this virus variant is? An overview.
Is Omikron even more contagious than the Alpha and Delta variants that were previously circulating in Europe, which in turn were much more easily transferable than the versions that dominated before?
It cannot be said for sure yet. B.1.1.529 has mutations near the so-called Furin Cleavage Site, a region that plays a role in the uptake of the virus into human cells. An improved transferability through these changes is conceivable, explains the Berlin virologist Christian Drosten. It has not yet been proven with certainty. The numbers in South Africa alone do not necessarily indicate increased transferability, among other things because the number of infections there has recently been greatly reduced and newly emerging outbreaks could appear oversized against such a very small background.
In the meantime, however, the international suspected cases and evidence are increasing – although the search for Omikron has mostly only been carried out specifically since Friday. The variant could therefore have spread far more widely than previously known. A case in Hong Kong, for which the details are known precisely because it happened in a quarantine accommodation, can be seen as an indication of higher transferability: According to the Hong Kong government, a traveler from South Africa brought the variant with him and presented it despite strict isolation passed on to a 62-year-old in the opposite room. Possible cause: insufficient face mask when accepting food through the hotel door. Both men therefore had a very rapidly increasing, rapidly very high viral load.
The EU health authority ECDC considers the likelihood of further introduction and spread of the variant in Europe to be high. When it comes to distribution, it is also important to consider: The geographical origin of Omikron does not have to be in South Africa, as Drosten explains. “Bordering countries that have strong travel connections with South Africa have less extensive virus surveillance than South Africa.” In addition, Johannesburg Airport is in the province where the virus was first noticed in South Africa.
How well do the vaccines currently in use protect against Omikron?
The manufacturers are currently carrying out initial laboratory tests and the results are expected in around two weeks. In any case, the genetic properties make experts fear about vaccination protection: B.1.1.529 has mutations in several crucial places. “Based on current judgment, one should assume that the available vaccines will basically continue to provide protection,” said Drosten. Protection against serious illnesses is particularly robust against virus changes.
Lothar Wieler, President of the Robert Koch Institute (RKI), emphasized that vaccination remains the best option even if it is less effective. “All people who get vaccinated do not start from scratch when they are infected with a new variant.” In any case, you already have a certain level of vaccination protection, which is crucial to know. According to the Berlin infection immunologist Leif Erik Sander, Omikron has many changes in places where the best antibodies can bind. “But our body makes a huge number of different antibodies.” In addition, there are special cells of the immune system, which usually recognize completely different locations than the antibodies. “So we always have a network and a false floor,” said the immunologist at the Berlin Charité.
What about the risk of a new corona infection?
“The genome changes indicate that this virus could show an immune landscape,” explains Drosten. The case in South Africa also makes it seem plausible that Omikron could bypass an immune defense built up against other Sars-CoV-2 versions: The currently detected infections take place to a very large extent in those who have previously recovered – so people who are already infected are infected were infected with Delta or another variant. In the case of South Africa, this alone could be an explanation for an increased transferability relative to the previously circulating delta virus. But it is also important to know, as Drosten emphasizes: According to scientific knowledge, “significantly more mutations” would be required in the spike protein for a complete failure of immune protection.
Are people infected with Omikron more sick?
“There is currently no evidence of a change in the severity of the disease,” emphasizes Drosten, head of virology at the Berlin Charité. According to the medical association SAMA in South Africa, those affected there have not become seriously ill so far. However, the analyzes on this are still at the beginning; South Africa also has different basic requirements – for example a different age structure – than countries like Germany. In addition, most people in South Africa became infected who had already recovered from another variant, i.e. who already have a certain level of immune protection. Statements about the course of the disease are currently not possible, says Carsten Watzl, Secretary General of the German Society for Immunology (DGfI). “We just have too few cases for that at the moment.”
If so many things about B.1.1.529 are not exactly known yet, why the great international concern immediately?
Omikron carries more mutations than any other variant known before, more than 30 of them in the spike protein, through which the virus docks to human cells. The body forms antibodies against the spike protein when it becomes infected with the virus. Many of the vaccines also stimulate the immune system to produce antibodies against this protein. In addition, there are – besides others with unknown possible consequences – the mutations near the already mentioned Furin Cleavage Site.
For the first time, Omikron combines critical mutations in the receptor binding site from the variants Alpha (first detected in England at the end of 2020), Beta (South African epidemic in the second half of 2020), Gamma (Brazil 2020) and Delta (India 2021 and now available globally), explained Drosten. To evaluate and classify the changes, more data is now needed. The virologist considers travel restrictions as a precautionary measure to be sensible: “Control of the spread by preventing flight connections to Germany is effective in the early phase of the introduction of infections and is therefore justified at the current time.”
How does Omikron’s detection work?
A conventional PCR test can only determine whether there is an infection with Sars-CoV-2, not with which variant. There are also variant-specific PCR tests that can be used to identify known virus variants such as Delta. Characteristic mutations are usually detected within the spike protein by means of PCR. Omikron shows a certain change that, according to the Robert Koch Institute (RKI), can show up in individual diagnostic tests similar to the alpha variant. Alpha is currently hardly widespread in Germany and other countries, the variant has been largely displaced by Delta – which makes detection of Omikron probable in a successful test. Until a test specially created for Omikron, however, only complete genome sequencing gives absolute certainty, according to the RKI.
Why Omikron and not Ny as a name?
The World Health Organization (WHO) has been naming conspicuous variants of Sars-CoV-2 after the letters of the Greek alphabet for some time. This is to prevent the places where the variants appear for the first time from being used as a designation and linguistically pilloried. Ny should have followed in the order – but the WHO left out this and the following letter Xi. Why? Ny, which means Nu in English, sounds too much like “new” and would therefore have been misleading, according to the WHO. “Xi was not used because it is a common surname.” Virus names should not harm ethnic or regional groups. Although Xi is common in China and in countries with a Han Chinese population, it is not a very common name, at least in China. However, there is one very important bearer of the name: the Chinese head of state Xi Jinping.