Covid-19: what we know about the XD variant

The Deltacron variant was first identified in January 2022 in Cyprus where a team claimed to have detected 25 cases. At that time, the scientific community had expressed doubts as to the real existence of this variant, suggesting contamination of samples instead. Then, in mid-February, the United Kingdom’s health security agency also declared a case of infection hybrid between the Delta variant and the variant Omicron. There too, it was rather mentioned an exceptional case of co-infection of a person by the two variants at the same time. During this same period, cases of co-infection had also been described with flu virus and the coronavirus. We then talked about Flurona, contraction between “flu”, the flu, and “coronavirus”. Nevertheless, and despite the doubts about the real existence of Deltacron, France decided to closely monitor this potential recombinant variant from February 18, 2022. It entrusted this work to the laboratories of the Emergen consortium, to Public Health France and to the CNR ( National Reference Center) for respiratory infection viruses. Since then, the name given to Deltacron is XD.

What we know about the genome of the XD variant

The XD variant results neither from contamination of samples nor from co-infection by two viruses of the same cell. This is indeed a new variant. According to epidemiological point of Covid-19 of March 24, 2022 from Public Health France, the genome of the XD variant consists of:

• the majority of the Delta variant genome (AY.4 sublineage);
• of the genome of the Omicron variant (BA.1 sub-lineage) on a small but strategic portion, the uncomfortable S which codes for the Spike protein.

As a reminder, the Spike protein is a protein present on the surface of the virus. It has the ability to bind to a human receptor, named ACE2. This receptor is widespread on the surface of human cells, in particular the lungs. Via this link, the virus penetrates inside our cells.

What we know about the spread of the XD variant in France

Still according to the epidemiological point of Covid-19 of March 24, 2022 from Public Health France, 44 cases have been detected on the territory. Several of these contaminations date back to January 2022, “ suggesting circulation of this recombinant at low levels for several weekss”. Nevertheless, the number of cases detected week after week does not seem to be increasing.

Legitimately, this variant is scary. Imagine a variant with the dangerousness of Delta and the contagiousness of Omicron! However, there is nothing to worry about at this time. The report states that ” to date, very little data is available on the characteristics of the XD variant, but investigations are ongoing “.

What we know about the first case of the Deltacron variant detected in the UK

Article of Stephanie le Guillou published on 02/19/2022

The number of cases of Omicron contamination continues to decrease in France: – 44% of new positive cases compared to last week on Monday February 14. The way out of the crisis seems to be taking shape… unless new, more contagious or more dangerous arise. A case of Deltacron was detected in the UK late last week. What is it about ? Should we be worried?

The Deltacron variant had already been talked about in early January. It would be a new variant of the coronavirus, resulting from a recombination between Delta and Omicron. A Cypriot team claimed at that time to have detected 25 cases of Deltacron. Therefore, serious doubts had been expressed as to the existence of this variant. Contamination of samples had been mentioned.

This Friday, February 11, the Deltacron variant returned to center stage: the United Kingdom health security agency indicated that it had detected a first case of hybrid infection. This variant, under the name “Delta x Omicron recombinant”, is now part of the list of variants “under surveillance” from the British authorities. So is it really a new variant?

A simple case of co-infection?

Before speaking of a new variant, it is necessary to eliminate the other explanations, in particular the case of a co-infection. You should know that the same cell can be infected by two viruses at the same time. From cases of influenza and SARS-CoV-2 infections have recently been reported. At that time, we very quickly heard about Flurona, a contraction between “flu” (the flu) and coronavirus. However, it was not a new virus or a new variant, but a patient who had been infected with both viruses at the same time. Regarding the case of Deltacron detected in Great Britain, it is very likely that the patient was infected with the Delta variant and the Omicron variant of SARS-CoV-2 at the same time.

More danger?

When you think about how dangerous Delta is and how contagious Omicron is, the word Deltacron is absolutely scary! At the moment, cases of Deltacron are extremely rare and the UK report is the only officially recorded case. The data are therefore not sufficient to conclude on this type of hybrid contamination. However, European populations now have a good level of protection against the Delta and Omicron variants, on the one hand thanks to the vaccination and secondly because of the high level of circulation of the Omicron variant in recent weeks. There is therefore no reason to worry about the occurrence of this new variant.

Even if the Deltacron variant does not seem to be one, the threat of the occurrence of new variants however, remains indisputable. As stated by the Director General of theWHO a few weeks ago, the risk ofemergence new, more transmissible and more lethal variants is “very real”.

Deltacron: does the new variant discovered in Cyprus really exist?

Article of Julie Kern published on 01/10/22

“Deltacron” is a term that made the rounds in the media this weekend. It would be a variant of SARS-CoV-2, a mixture between Delta and Omicron, discovered in Cyprus. The real existence of this new variant is not yet unanimous.

Saturday January 8, 2021, the press agency Bloomberg published information which quickly made the media rounds. Leondios G. Kostrikis, a biochemist Cypriot and head of the biotechnology and molecular virology laboratory at the University of Cyprus, discovered a new variant of the coronavirus, resulting from the recombination between the Delta and Omicron variants. The scientist shared his discovery, called “Deltacron” on the Sigma TV channel during an interview on January 7, 2021.

The Delta variant with genetic signatures of Omicron

The Deltacron genome would be largely similar to that of the Delta variant, but would possess Omicron-specific mutations. Leondios Kostrikis and his team claim to have detected 25 cases of Deltacron. The sequences of the latter were transmitted at Gisaid by Cypriot scientists, a database which groups the sequences of the coronavirus variants, but Deltacron is not yet part of the list of variants listed by the site.

Indeed, the discovery of Deltacron leaves many scientists skeptical. Tom Peacock, virologist at theImperial College from London, spoke on Twitter about it. For him, it is a problem of sample contamination rather than an actual recombination event.

A variant that does not exist?

Leondios Kostrikis said to Bloomberg, on January 9, 2021, that the 25 samples were not sequenced at the same time, which, according to him, excludes any technical error. Moreover, he does not believe that Deltacron is the result of the recombination between Delta and Omicron in a patient co-infected by the two variants, but rather the result of the natural evolution of an older variant.

So does the Deltacron variant really exist? It’s hard to tell from these things alone. To confirm the existence of Deltacron, other similar observations must be made independently repeatedly, and in different laboratories.