Coronavirus

Mutation B.1.1.7 and B.1.351: How dangerous the new gene variants are

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There are only minimal changes in the genome, but they are tough. Some new variants of the novel coronavirus are spreading much faster than those initially circulating because they are more contagious. What follows from this: In the long term there will be more infected people, more sick people, a higher burden on the health system – and ultimately more deaths.

Variant B.1.1.7, which was first discovered in Great Britain, has also been in Germany since November. The Hanover Medical School was able to prove this in retrospect. She discovered the B.1.1.7 in the samples of a very old Covid 19 patient with previous illnesses and his wife. The two were believed to have contracted their daughter, who was in England in November.

The variant has now been found in some federal states of Germany: in patients in Baden-Württemberg, Saxony, North Rhine-Westphalia and also in Berlin. The number of unreported cases is likely to be high, as the virus genome of people infected with corona has not yet been analyzed on a large scale in Germany – which, according to Federal Health Minister Jens Spahn (CDU), should now change. According to a draft of the Federal Ministry of Health for a new Corona regulation, the laboratories in Germany should search for dangerous mutations much more intensively.

In the meantime, variant B.1.351 (also: 501Y.V2) of the coronavirus, which appeared in South Africa for the first time in August, has also been detected in Germany. The South African government had reported that they had seen a rapid increase in infections with the variant since mid-December. The Baden-Württemberg Ministry of Social Affairs has now confirmed the infection with the mutation in a person who had returned with their family from a longer stay in South Africa.

In variant B.1.1.7, the R value is 0.4 to 0.7 higher than before

The mutations are currently worrying science and politics – and rightly so. The tightened lockdown that is now in force was also justified by the new gene variants, the danger of which can only be roughly estimated, but cannot be said with certainty. What we know so far is that the mutations are probably not “more dangerous” per se, so they do not worsen the course of the disease – but they do ensure that the virus is infected more quickly. What may sound like the lesser evil at first, could actually be extremely dangerous for the further course of the pandemic.

Researchers led by Erik Volz from Imperial College London have shown how much more contagious B.1.1.7 is and what follows from it for the infection process. According to the researchers, the R value for the mutation in Great Britain is 0.4 to 0.7 higher than before. That’s a lot. With an R value of 1, 100 infected people infect 100 more people – but with an R value of 1.7 it is 170. The new mutation is therefore up to 70 percent more contagious than the previous ones.

It is important that the R-value of 1 is considered a dangerous threshold: higher values ​​represent the exponential growth in the number of infections. A faster infection, that means an even higher risk for an exponential growth in the number of infections and thus a much more difficult contact tracing – which is hardly given in Germany in view of the high incidence values. According to the Robert Koch Institute, the R value in Germany is currently around 1.1. With the new variant, experts see even greater disaster looming in the sky. Even under the current conditions, the infection process can hardly be brought under control.

And the more people become infected, the more they are three to four weeks later in the hospitals, sometimes in the intensive care units – and in the worst case they die. The Saarland Prime Minister Tobias Hans (CDU) had told the newspapers of the Funke media group before the new lockdown decision that the federal and state governments should not take any risks – especially with regard to the new gene variant B.1.1.7 with its increased risk of infection. “Our hospitals are at the limit of their resilience, and without an extension of the lockdown we will not get the situation under control permanently.”

Measures need to be stricter to achieve the same containment effect

Based on the available data, it seems likely that B.1.1.7 will soon also be the dominant variant in this country, says the virologist Jörg Timm from the Düsseldorf University Hospital. That would result in a significantly higher R without the other conditions having to change. “I think a reduction in the number of cases is fundamentally necessary for sustainable infection control,” says Timm. “If the data on the increased infectivity of the new variant is correct – and I assume it – then the task will certainly be more difficult.”

Because the variant is spreading faster, measures would have to be stricter to achieve the same effect in containment. Adam Lauring, an expert on the evolution of RNA viruses at the University of Michigan in the United States, said this in a podcast. “We need to get better at measures to control the virus. If not, we will see more corona cases. ”With a delay, that means more serious illnesses – and more deaths.

The reverse is also true: If the immensely high numbers of infections in Europe, the USA and other countries had been better contained, the new pathogen might never have existed. In particular, variants with a complex mutation pattern as in B.1.1.7 are rare, explains Timm. With high numbers of infections, however, the probability increases that they arise and are spread. “From this point of view, too, high numbers of infections can be problematic for the course of the pandemic.”

Mutations, i.e. random changes in the genome, are normal in viruses. Most of them are harmless. However, some mutations give the pathogen advantages, for example by making it easier to transmit. In addition to B.1.1.7, this could also apply to the second mutation, B.1.351, about which less is known so far. As with gene variant B.1.1.7, changes in the spike protein are noticeable here, experts say. With this, the virus docks to body cells in order to penetrate them. The mutations give the virus easier access to certain receptors and therefore make it potentially more contagious.

The spike protein is also the indirect target of the RNA vaccines approved in Germany from Biontech / Pfizer and Moderna. The good news with all the uncertainty about the mutations: The vaccine from Biontech and Pfizer at least works against the two new gene variants. This is shown by a new laboratory study.

fj / with dpa

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