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Deltacron: Variant, Scariant or Celebrity Coupling?

Hot on the heels of last week’s ‘French variant’ and alerts about cases of ‘flurona’ - co-infection with both COVID-19 and flu – the mainstream media lit up again this weekend with reports of a controversial new ‘Deltacron’ variant.

Allegedly a combination of the Delta and Omicron strains of COVID-19, the latest variant was claimed by Leondios Kostrikis, professor of biological sciences and head of the laboratory of biotechnology and molecular virology at the University of Cyprus.

As reported on Saturday by Bloomberg, Prof Kostrikis told Cyprus broadcaster Sigma TV that he and his team had identified 25 such cases in Cyprus, with their sequences sent to GISAID, the international database that tracks virus sequences, on January 7. 

Prof Kostrikis was quoted as saying in the interview: "There are currently Omicron and Delta co-infections, and we found this strain that is a combination of these two." The team dubbed their discovery 'Deltacron', due to the identification of Omicron-like genetic signatures within the Delta genomes, he said.

Of the 25 samples, 11 came from people in hospital with coronavirus, and 14 from the community. The frequency of the mutations was proportionately higher among hospitalised patients, which could imply a correlation between Deltacron and hospitalisations, he said.

"We will see in the future if this strain is more pathological or more contagious," and if it will prevail over Delta and Omicron, he said, though he believes that this strain will also be displaced by the highly contagious Omicron variant.

Contamination or Co-Infection?

The discovery has provoked fierce controversy however, with Prof Kostrikis forced to defend his finding  against numerous sceptical experts.

Virologist Tom Peacock, PhD, a researcher from Imperial College London, said the Cyprus variant "looks to be quite clearly contamination". There are already numerous reports of Omicron sequences carrying Delta-like mutations such as P681R or L452R, he said.

"Although a subset of these might end up being real, the vast majority will most likely turn out to be contamination or coinfection. No clear signals of anything real or nasty happening (yet)," he tweeted. "True recombinants don’t tend to appear until a few weeks/months after there’s been substantial co-circulation – we’re only a couple of weeks into Omicron – I really doubt there are any prevalent recombinants yet."

Even more emphatically, Dr Krutika Kuppalli, an infectious diseases physician  with the World Health Organisation (WHO) posted on Twitter: "There is no such thing as #Deltacron (Just like there is no such thing as #Flurona). #Omicron and #Delta did NOT form a super variant. This is likely [a] sequencing artifact (lab contamination of Omicron fragments in a Delta specimen)." She was also reported as saying: "Let’s not merge of names of infectious diseases...  leave it to celebrity couples."

Medscape Editor-in-Chief and molecular biologist Eric Topol of the Scripps Research Translational Institute, tweeted: "Deltacron is a scariant. One less thing to worry about."

Dr Jeffrey Barrett, director of the COVID-19 genomics initiative at the Wellcome Sanger Institute, told the Science Media Centre: "This is almost certainly not a biological recombinant of the Delta and Omicron lineages. The apparent Omicron mutations are located precisely and exclusively in a section of the sequence encoding the spike gene (amino acids 51 to 143) affected by a technological artifact in certain sequencing procedures." The Wellcome Institute published a technical description of this issue last year, he said.

Scientist Claims to have Found Another 52 Cases

Meanwhile Prof Kostrikis fought back, saying his finding is not an error and telling the Cyprus Mail yesterday that his team has already found another 52 cases of the combination strain in addition to the initial 25 individuals.

While saying that the new variant was not something to worry about at the moment, Cyprus’ health minister Michalis Hadjipandelas rallied to Prof Kostrikis' defence, saying that this research puts Cyprus on the international map when it comes to health matters, reported the Jerusalem Post. "The groundbreaking research and findings of Dr Kostrikis' team make us proud of our scientists," he said.

Medscape UK has reached out to Prof Kostrikis for further comment but did not hear back in time for press.