The type of coronavirus detected in Congo must be closely monitored, and this is why

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The B.1.640 variant has been discovered in the Congo and several cases have been observed in France and other countries, but its characteristics and true origin remain a mystery.

CORONAVIRUS – “You may have heard of the Congolese variant.” Asked Tuesday, November 16 before West of France Regarding the risk of the emergence of new types of coronavirus, Olivier Veran evaluated a form of SARS-CoV-2 virus that was recently discovered in the Republic of the Congo and in 3 regions of France.

The Minister of Health (even if he is not) said: “I am not saying that it is a cause for concern, nothing to indicate that this alternative is particularly dangerous, but to emphasize that our ability to track variables is a very strong case).

However, this variant has had an official name since then, which is B.1.640. He has not yet inherited Greek rhetoric because the World Health Organization does not consider it a “substitute for concern or concern”. But health authorities recently classified him as “under surveillance.” BritishAnd European And French, because the existing mutations raise concerns about reduced efficacy of vaccines or significant transmissibility.

However, Olivier Veran is right to point out that we shouldn’t be concerned about nothing. “We are now unable to determine whether this variant will die or evolve,” he explains HuffPost Etienne Simon Laurier, a virologist at the Pasteur Institute who worked on the French sequences. Especially since the delta variant at the moment seems to crush other breeds. But this variant B.1.640, discovered in the Congo, is still closely monitored. Because if it is impossible to determine whether he can beat the omnipresent delta in France, then there are many characteristics that worry specialists.

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The original alternative to the Congo

The oldest genome The history of the coronavirus for this sequence variant dates back to September 28 and comes from the Republic of the Congo. Since then, 28 different species of B.1.640 have been identified worldwide, including 12 in France and 4 in Italy. Sporadic cases were found in Holland Or even in Spain and the United States.

This kind of thing happens very regularly. As mentioned in previous articles, Sars-Cov2 mutates regularly, like all viruses. These mutations are often harmless, like a typo. But sometimes, if they’re in the right place and the right combination, they can change the behavior of the virus. As if several random misspellings changed the meaning of the text.

Because a version with several observed mutations of the coronavirus appears, it is very common. Specifically by observing the many non-hazardous variables, we make sure not to miss the next delta variable. Sometimes, all it takes is a stroke of luck for the alternative to feel like it’s spreading out into the world. It is enough for an infected person to infect several people at an airport, for example.

If this B.1.640 variant is monitored, it is above all because it contains an astonishing “genetic diversity”. “The different sequenced genomes that we discover that we assign to this line have some dissimilar mutations,” he explains. HuffPost Florence Debar, a researcher at the National Center for Scientific Research, is an evolutionary biologist. These mutations are not dangerous, but they are useful for researchers to go back in time.

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Simply put, we know that the coronavirus changes on a regular basis, say every 7 days. By looking at these mutations, we can build a kind of genealogical (or rather, genomic) tree to follow the evolution of these viruses. The fact that this B.1.640 variant discovered in Congo presents forked mutations may mean that it is not very young.

“One possibility is that this variant has been potentially circulating at low noise for some time, in Africa or elsewhere, in places where genome control is weaker,” explains Etienne Simon Laurier. An important subtlety, the researcher notes: It is possible that part of this diversity is related to human or technical errors during the sequencing of these viruses.

As long as we don’t see this B.1.640 variant predominating over the delta variant, we don’t have to worry. In France, where a cluster has been detected in Brittany as well as a few sporadic cases in Ile-de-France and PACA, Public Health France is not concerned, because there is no significant spread or progression. In addition, the effect of this series of mutations on the SARS-Cov2 virus on its transmissibility or on a partial decrease in the efficacy of vaccines is not yet clear.

“Studies are underway at the National Reference Center, but this requires high-quality samples to isolate the variant and test it in the laboratory,” explains Etienne Simon Laurier. Health authorities will also continue to monitor the evolution of the number of genomes associated with the B.1.640 variant.

In the Congo, on the other hand, sequencing and screening are very limited to know what is actually going on. Étienne Simon Laurier recalls: “Especially since, in some African countries, the delta variant has not yet dominated as in France.” It is therefore possible that other forms of the coronavirus may be spreading underwater in countries with little epidemiological surveillance.

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Besides, B.1.640 is also of interest when searching for the closest ‘common ancestor’. “You have to go far, it is very difficult to find out where it came from,” the researcher regrets. It is clearly not a classical derivative of the great known variables, from delta to alpha via gamma and beta.

Whether or not this Congo variant is imposed in the world is perhaps the most important. “It was said that Delta had become dominant and that the next variant would be one of its descendants. There, there is another very different branch, a line that seems to have lived its life off the radar,” Florence Debarre recalls. “This reminds us that many copies of the coronavirus are circulating in many parts of the world where there is very little genetic monitoring and where very few doses of the vaccine have been received.”

See also on HuffPost: Why are some variables necessary and others not? (explained in video games)


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