Leondios Kostrikis, professor of biological sciences at the University of Cyprus, said that the hybrid strain has a similar genetic structure to Omicron with the genomes of Delta.
The discovery was named “Deltracron” due to having characteristics of both variants.
What is known about Deltacron?
Professor Kostrikis announced the discovery of “Deltacron” in an interview with Sigma TV on Friday (7 January).
He said that his team had identified 25 cases of the hybrid strain so far, but it is still too early to assess its potential impact.
Of those identified, it is understood that 11 patients were already in hospital with Covid-19, while the remaining 14 cases were among the general public.
Speaking to Sigma TV, Prof Kostrikis said: “There are currently Omicron and Delta co-infections and we found this strain that is a combination of these two.
“We will see in the future if this strain is more pathological or more contagious or if it will prevail.”
The team are understood to have sent their findings to GISAID, an international database that tracks viruses.
Is Deltacron real?
Health experts have been skeptical over the announcement of “Deltacron” and dismissed claims that a new hybrid of the Delta and Omicron strains has emerged.
Infectious-diseases physician Dr Krutika Kuppalli, who works at the World Health Organisation, said that the strain “is not real” and is likely a result of lab contamination.
Writing on Twitter, she said: “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 sequencing artifact (lab contamination of Omicron fragments in a Delta specimen).”Global health expert Dr Boghuma Kabisen Titanji also expressed doubts about the claims and warned people to interpret reports “with caution”.
She said: “The information currently available is pointing to contamination of a sample as opposed to true recombination of #delta and #omicron variants.
“With transmission levels of #SARSCoV2 at all time highs globally, it is likely that recombination is occurring and may rise to levels that we start picking up these events more frequently. Will this lead to more concerning variants? That is possible but nobody knows.
“The best thing we can do besides worrying about it and coining variant names that sound like a “Transformers” villain, is ensuring that vaccines are available to everyone and combining vaccination with other strategies that give the virus fewer opportunities to spread.”
Imperial College virologist Dr Tom Peacock agreed that the emergence of the strain is likely due to low level contamination.
In a Twitter post, he explained: “Lots of reports of Omicron sequences carrying Delta-like mutations (eg P681R or L452R). 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).
“To be sure a signal like this is real you really want multiple sequencing labs finding the same recombinant/homoplasy independently (or at least on different sequencing runs) - ideally you would look into the raw seq files as well and show no mixed bases.
“As far as I understand it these are appearing now for two reasons:1) Lots of Delta and Omicron circulating in the same areas2) Some older sequencing primer sets being less effective at picking up parts of Omicron so low level contamination with Delta being selectively picked up.”
Dr Peacock added that mutations of the Delta variant have been “turning up for ages” and are nearly always explained by low levels of contamination.
He said: “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.
“Omicron-like mutations in the Delta backbone all fall within the infamous amplicon 72 - which does not pick up this region of Delta in Artic primer V3
“Because amplicon 72 of Delta is very poorly picked up, any contamination, even at miniscule levels, will get preferentially amplified (because PCR is an exponential process) and you end up with hybrid sequences.
“Delta sequences with strange mutations in amplicon 72 have been turning up for ages (for example Delta + Mu NTD insertion) however they always show this non-monophylotic pattern and are nearly always more easily explained by this primer issue exacerbating very low level contam.”
The UK Health Security Agency (UKHSA) has no new variants under surveillance and is not concerned about the reports emerging from Cyprus, The Telegraph reports.
This article originally appeared on our sister site, NationalWorld.