Scientists say contamination in the lab is likely responsible for ‘deltacrine’

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Scientists said that the apparent strain of coronavirus that combines mutations from both omicron and delta variants is likely the result of laboratory contamination.

Concerns emerged over the weekend that a new strain of Covid, dubbed ‘Deltacron’, could emerge from a so-called recombination event — when two different species infect a patient and exchange mutations to produce new viral offspring.

Twenty-five Deltacron sequences have been reported so far, but experts insist there is no evidence to suggest Omicron and Delta have combined to generate a new variant.

“This is almost certainly not biocompatible for Delta and Omicron strain,” said Dr. Jeffrey Barrett, director of the Covid-19 Genome Initiative at the Wellcome Sanger Institute.

Alternatively, it has been suggested that parts of Omicron were mistakenly inserted into the delta genetic make-up during the sequencing process that occurs when trying to identify the infection of a Covid variant.

This is a common mistake that can occur in any laboratory, said Aris Katzorkis, professor of evolution and genomics at Oxford University.

He explained that when a virus is sequenced, its genome is broken down into genetic parts and then analyzed before being reassembled into a computer.

However, a certain portion of delta is susceptible to “leakage” during the sequencing process and is “sensitive to contamination”. Professor Katzurakis said that in the case of the 25 “Deltacon” samples, this particular gap appears to have been filled by a portion of Omicron.

“This is a telltale sign of laboratory contamination that gives the impression of recombination.”

Dr Barrett said Deltacron mutations that appeared to be derived from Omicron were located “precisely and exclusively” in the portion of the delta genome that was “influenced by a technological artifact in certain sequencing procedures”.

The 25 samples reported to Gisaid, a global variable database, were processed in multiple sequencing procedures in more than one country, according to Leondios Kostrikis, a professor of biological sciences at the University of Cyprus who first got to know Deltacron.

“These findings refute undocumented statements that Deltacron is the result of a technical error,” said Professor Kostrikis.

However, Professor Katzurakis said that the act of accidentally combining parts of the variants when sequencing too many Covid samples in the lab was a “common mistake”. This “happens all the time,” he added.

“Not that it is impossible to recombine between variables. Only, this is not proof of that.”

“If it is a true recombination event, then when you make a tree of Delta and Deltracron sequences, the Deltacon sequences should form a distinct branch in that tree, indicative of their common origin.

“What you see instead, is a mixture of Deltacron sequences within the delta tree. This means that they do not form a distinct lineage.”

No matter how it happened, experts and officials do not care about Deltacron.

“There is no need to worry,” said Professor David Matthews, a virologist at the University of Bristol.

Cypriot Health Minister Michael Hadjipantila said on Sunday that Deltacron is not a concern, and more details will be provided at a press conference later in the week.

Professor Lawrence Young, a virologist at the University of Warwick, said the focus of the broader scientific community should be on how to “manage the inevitable emergence of new variants and how to validate and report them.”

Variants will continue to emerge as long as the virus continues to circulate in unvaccinated areas. This is why universal vaccination is so important. “

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