what we know about this new strain of Sars-CoV-2, detected in several countries including France

what we know about this new strain of Sars-CoV-2, detected in several countries including France
what we know about this new strain of Sars-CoV-2, detected in several countries including France

The summer season is threatened in Europe by the spread of the Delta variant, 40 to 60% more contagious than the Alpha variant (which had appeared in the United Kingdom). The Delta variant, first identified in India, currently represents 20% of new cases of Covid-19 detected in France, according to the Minister of Health, Olivier Véran. It is on the way to become predominant on the Old Continent by the end of August, the European section of the WHO warned on July 1. To this concern is added that of seeing another variant, the Delta Plus variant, already detected in several European countries, following the same rise.

Should we be worried? How does it differ from the Delta variant from which it comes? Franceinfo draws up the portrait of this new variant of Sars-CoV-2, already tracked by the health authorities.

Appeared in India, it is classified as “of concern” by local authorities

Sequenced in Europe and India in the spring, this new strain was found in several infected people in India in June, a country severely affected in April by a deadly wave due to the Delta variant. The identification of a few cases of this new strain, dubbed Delta Plus, quickly raised concern among Indian health authorities, who fear a new epidemic resurgence. The new mutation was detected in only 48 people infected with the Delta variant, out of more than 45,000 samples examined, the site notes The Conversation (article in English), but in three states across the country: Maharashtra, Kerala and Madhya Pradesh.

Despite its reduced incidence, the Delta plus variant was classified on June 22 by the Indian government as “worrying”. In a statement (in English), the Ministry of Health justifies its choice. According to information provided by Insacog, a consortium of 28 laboratories affiliated with the Ministry of Health, the Delta Plus variant would be more transmissible, would have a greater ability to attach to lung cells and would be more resistant to monoclonal antibodies. However, these elements are not yet corroborated by consolidated studies. “We are only on guesses, everything comes from a press release from the Ministry of Indian health“, admits Mircea Sofonea, lecturer in epidemiology and evolution of infectious diseases at the University of Montpellier,on France Culture.

It carries a mutation of the Beta variant

This new strain of the Sars-CoV-2 virus, at the origin of Covid-19, belongs to the lineage of the Delta variant identified in India at the end of 2020. It has the characteristic mutations of this variant, but also a mutation called K417N. The detection of this additional mutation by scientists gave rise to the name of a new variant, called AY1 by epidemiologists and Delta Plus by the authorities.

This K417N mutation is not a novelty in itself: it has already was identified on the Beta variant, first discovered in South Africa at the end of 2020. Located at the level of the genetic sequence encoding the Spike protein, which allows the virus to enter the cells of the human body, it would be responsible for a larger exhaust. That is to say that this mutation would allow the virus to escape more easily the anti-Sars-CoV-2 antibodies created by the body after contamination or vaccination.

In the case of the Beta vaccine, the Covid-19 vaccines had retained their effectiveness, despite this mutation, but some were found to be significantly less effective against this strain of the virus. We end up with a Delta variant which has in addition, possibly, an immune escape capacity because this mutation has already been found on the Beta variant, formerly known as ‘South African’ “, summarizes epidemiologist Mircea Sofonea. Adverb “eventually” has all its importance here, because for the time being it is not known what happens for the Delta Plus variant. However, studies are underway to assess the protection offered by vaccines against this new variant.

It is monitored globally

For the moment, in particular because of its low circulation, the Delta Plus variant remains labeled by the WHO as a “variant of interest” and has not progressed to the level of “variant of concern”. The new strain does not represent “only a small fraction of the Delta sequences ” identified in the Sars-CoV-2 genomes analyzed, justified the organization.

This new strain is present in several countries around the world, notably in France, the United Kingdom and Portugal, but in a very small proportion: according to the Outbreak site (in English), which visualizes the circulation of the different strains of the virus from to the database Gisaid, this variant represented, as of July 4, less than 1% of the tests sequenced in the countries where it was detected, except in Nepal (7%). In France, saccording to the latest risk analysis report produced by Public Health France and the CNR for respiratory infection viruses (document PDF) dated June 30, the AY1 lineage, which corresponds to the Delta Plus variant, is sporadically detected “ with 8 cases detected out of more than 53,000 sequences analyzed, based on data provided by the Gisaid virological database.Note that the proportions analyzed using this platform depend on the sequencing effort provided by the different countries.

The fact that a variant has mutated is nothing new, the Alpha and Beta variants have also given rise to new strains of the virus, which, however, have not yet established themselves. Nothing suggests that the Delta Plus variant will take the upper hand over its cousin, the Delta variant. “At the moment we are short of data, which is why it is still a little too early to declare the Delta Plus variant as a ‘variant of concern’ on a global scale”, explains Mircea Sofonea. “The Delta Plus variant is almost identical to the Delta variant”, underlined on June 23 the director of the CSIR-IGIB Genomic Research Institute in New Delhi, Anurag Agrawal,

(in English), assuring : “The ‘Plus’ doesn’t necessarily mean it’s worse than Delta.”

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