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A researcher from Cyprus told local media that he identified a combination of the Delta and Omicron variants. But for many experts, this is a sequencing error, an accidental mixing of samples.
Deltacron. The term returned to Twitter this weekend after the announcement by University of Cyprus professor Leondios Kostrikis on Friday, January 7. He claims to have discovered a combination of the Delta and Omicron variants, due to the identification of Omicron-like genetic signatures in the Delta genomes.
“There are currently Omicron and Delta co-infections and we have found this strain which is a combination of the two” he told local Sigma TV according to Bloomberg. The researcher and his team have identified 25 cases and the genetic sequences have been uploaded to an international database, GISAID. Among these cases, 11 came from hospitalized people, we learn in the Cyprus Mail.
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A probable sequencing error, according to experts
But experts have reservations about this new information. The virologist at Imperial College London Tom Peacock, which has access to the database, indicates that the direct debits “do not cluster on a phytogenetic tree”. He explains thatit could be a series of accidental contamination from samples. It could come from a handling error. “Potentially mixing small amounts (…) in sequencing labs – which then gives the impression that the virus has mixed in real life – happens quite often because tiny volumes can cause this problem”, he noticed. The 25 reported cases could therefore have been sequenced on the same day and in the same place.
Small update: the Cypriot ‘Deltacron’ sequences reported by several large media outlets look to be quite clearly contamination – they do not cluster on a phylogenetic tree and have a whole Artic primer sequencing amplicon of Omicron in an otherwise Delta backbone.
– Tom Peacock (@PeacockFlu) January 8, 2022
Etienne Simon-Lorière, head of the evolutionary genomic unit of RNA viruses at the Institut Pasteur told the Parisian, “Tom Peacock’s analysis is very good. The tree distribution of these sequences is revealing, and these sequencing problems are very common, including with Omicron.”
Arnaud Fontanet, epidemiologist at the Institut Pasteur and member of the Scientific Council was notably questioned on this subject on Monday January 10 on RMC / BFM TV. He “set aside” the hypothesis of a new variant and confirms the thesis of Tom Peacock. According to him, no significant variant of concern has been noticed since Omicron. “We will always have new variants (…) as we go along, this is the occasion for a new layer of immunity either by a booster dose or because we have been infected. can hope that the emergence of the new variants will be accompanied by epidemics with colds, tonsillitis and much less severe forms “. Leonidos Kostrikis maintained his version in a letter sent to Bloomberg Sunday January 9. He nevertheless clarified that this discovery was not of concern and that this combination will not replace Omicron.
In addition, a variant was discovered by the IHU of Marseille, named B.1.640.2. Few data are available: the patients tested come from Forcalquier in the Alpes-de-Haute-Provence. Professor of pharmacy and virologist at IHU Philippe Colson indicates to France 3 regions that 12 people would be infected. More research is needed to find out more.
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