Is this the virus variant that is even more contagious than Delta? Or even one that is so different that the vaccine no longer adequately protects and has to be adapted or updated? To be very clear: Nobody can finally answer these crucial questions now.
Far too little is still known about the Sars-CoV-2 variant B.1.1.529, which was detected for the first time in South Africa. But there is definitely cause for concern, for precautionary measures such as those in Great Britain, the USA and now also Germany, Austria, Italy, the Czech Republic and Malta with entry restrictions from South Africa. “This newly discovered variant worries us,” said the still incumbent Federal Health Minister Jens Spahn on Friday morning. “That is why we are acting proactively and at an early stage.” The last thing that is missing now is a “new variant that has been introduced that causes even more problems”. Until the restriction came into effect, he called on returnees from South Africa to voluntarily undergo a PCR test and to be quarantined until the result.
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The main reason for concern is the amount of mutations in B.1.1.529. In the gene for the S protein alone, the sting with which the virus enters the cells, the researchers count 32 mutations, more than twice as many as in the Delta variant. The sheer number of changed genetic components (compared to the original virus) alone is not the decisive factor. Since the beginning of the pandemic, innumerable virus variants have emerged, counting dozens, hundreds and thousands of mutations, but as quickly as they came, they also disappeared again – either because they were no longer able to survive due to the abundance of changes or despite their good ability to infect and reproduce had no survival advantage over relatives who were already in circulation.
But in B.1.1.529, some of the 32 mutations are in positions that researchers have already identified as crucial for the infectivity of the virus, such as positions 655, 679 and 681 in the virus genome. There is the point in the S-protein’s genetic blueprint where the sting has to be cut by human enzymes so that the virus can penetrate the cells.
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The better this works, the sooner the virus can multiply in the upper respiratory tract, for example, where it is more likely to be transmitted to the next person with the next breath or cough. Other mutations probably also contribute to the increased infectivity, for example at positions 203 and 204 in the genome of B.1.1.529, where the blueprint for the “nucleocapsid”, the nuclear envelope of the virus, is located.
In addition, B.1.1.529 has some mutations that could enable the virus to at least partially escape the attack of neutralizing antibodies, such as those sent by the immune system of a vaccinated or recovered person to fight it: a so-called “immune escape”. Structural biologist James Naismith from the University of Oxford said on Friday on a radio broadcast on the BBC that he was “almost certain” that the previous vaccines protect fewer effectively against B.1.1.529 than against the previous variants, such as Delta or Beta.
From the point of view of the South African virologist Shabir Madhi, conventional vaccines only protect against the new Corona variant B.1.1.529 to a limited extent. He told the TV broadcaster eNCA in Johannesburg on Friday: “We assume that there is still some protection”, but it is likely that previous vaccines are likely to be less effective.
“Since the vaccines are efficient against all previous variants, I assume that there is also vaccination protection against this variant,” says Richard Neher, an expert on virus evolution at the Biozentrum of the University of Basel. In his opinion, the cellular immune reaction, i.e. not based on antibodies but based on T cells, should be “robust”. “However, it is quite conceivable that it would [mit B.1.1.529] Breakthrough infections are increasing, so a third dose is all the more important. “
However, these statements are not based on tests with the new South African variant, but on experience with viruses that sometimes carry mutations similar to B.1.1.529. In laboratory tests with viruses modified in this way, neutralizing antibodies from the blood of vaccinated or convalescent patients were no longer as effective as with other coronavirus variants. The lack of a piece of genetic material in section 105 to 107 should also contribute to the fact that the viruses are no longer recognized and fought so well by certain defense reactions of the cells, the cellular, innate immune system, which ultimately can also contribute to the transferability of the viruses.
B.1.1.529 already displaces the delta variant
The information about the distribution of the variant shows that the connection of all these properties with the mutations is not just about molecular biological coffee grounds reading. In the Kwazulu-Natal region, B.1.1.529 is already replacing the delta variant, which means that it is now more common than delta in the sequenced samples.
The experts are observing something similar in other regions of South Africa, and at breathtaking speed. In the Kwazulu-Natal region, the proportion of B.1.1.529 samples increased from 1 percent frequency to 30 percent within just two weeks. Almost all South African regions detected the variant on Thursday.
It is rather unlikely that this is just a “founder effect”, i.e. the chance occurrence of this variant in one or more outbreaks and a massive spread resulting from them. Because while Delta and previous virus mutants took many weeks to become the predominant variant, B.1.1.529 catapulted itself to the top of the infection statistics within 14 days.
This means that, according to initial estimates, B.1.1.529 could have a 500 percent infection advantage over the original variant, Delta has a 70 percent advantage. The variant has also appeared outside of South Africa, for example in Hong Kong, brought in by a traveler who infected another person in his hotel, according to investigations by the authorities there. Israel has also already reported the case of a passenger arriving from Malawi.
The first B.1.1.529 case in Europe was discovered in Belgium. The Belgian Minister of Health Frank Vendenbroucke announced on Friday afternoon. The German Robert Koch Institute has not yet been reported to a B.1.1.529 case, said RKI director Lothar Wieler on Friday morning in the federal press conference, but he is observing the situation “with great concern”. The World Health Organization has now upgraded the variant from “of interest” to “worrying” and given it the name “Omikron”.
New virus variant provides enough arguments for travel restrictions
Sufficient arguments for rapid travel restrictions are definitely – especially against the background of the, bad, experiences with the spread of the delta variant, which failed to contain, not least because border controls were too late.
Whether the variant will also lead to a more aggressive course of the disease, more frequent serious illnesses and even more deaths, is so far not foreseeable, simply due to a lack of information. The lesson from the experience with Delta is that a much more infectious variant alone increases the frequency of serious illnesses. Because if more people are infected, more can become ill.
It is important to emphasize that this variant can still disappear. The absolute number of people infected with B.1.1.529 is still low in South Africa compared to Delta. But the scenario in which this variant has now occurred is cause for concern, but it shouldn’t surprise anyone: In South Africa, 75 percent of the population are still not vaccinated, also because there is a lack of vaccine, which rich countries like the EU as before, do not make them available in sufficient quantities, as the World Health Organization (WHO) has been lamenting for months.
This is the breeding ground on which these variants arise, because every single infection of a person gives the virus millions of opportunities to generate new mutations as it multiplies. In addition, in South Africa there are many HIV-infected people whose immune systems are weakened when they cannot take their antiviral drugs regularly. In such immunocompromised patients, the viruses can accumulate more mutations because the body has less to oppose their reproduction, experts suspect.
The scientist Susan Hopkins of Imperial College London described the new variant as “the most worrying we have ever seen”. The transmission rate (R value) determined so far in South Africa is 2. Even more data are needed to come to a final assessment. A renewed increase in infections in a heavily contaminated country like South Africa suggests that new variations are at least partially responsible, Hopkins continued. Should a higher transferability prove to be true, the variant would be “a massive problem”. (with smc / dpa)
