Social media has been lively recently with reports from Cyprus and France claiming to have found a new hybrid variant of SARS-CoV-2. Dubbed Deltacron, it appears to be a combination of the Delta and Omicron variants. However, many experts have questioned whether this is truly a new variant, suggesting some cases may be due to contamination during laboratory testing. Medical News Today looks at the arguments on both sides.

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Is there a new SARS-CoV-2 variant on the loose? Image credit: Jason Alden/Bloomberg via Getty Images.

On January 7, scientists in Cyprus reported that they had discovered a new variant of SARS-CoV-2. The variant, named Deltacron, is said to be a hybrid of Delta and Omicron.

The scientists are led by Dr. Leondios Kostrikis, a professor of Biological Sciences at the University of Cyprus.

Dr. Kostrikis reported that the variant has a Delta-like genome with Omicron characteristics. The team stated that Deltacron had been identified in 25 individuals — some hospitalized and some in the community.

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Most recently, a pre-print study claimed to have found the first solid evidence of an Omicron and Delta recombinant virus. Genetic recombination is a process in which two variants infect the same host cell.

The researchers said that the hybrid version of the coronavirus they found—which they called “Deltamicron”— combines the backbone of the Delta variant with the spike protein of the Omicron variant.

They said they had identified it in three individuals in France so far, and estimated that it had been circulating since early January 2022.

The World Health Organization (WHO) has said it will be “tracking and discussing” the situation.

Earlier reports about this recombination surfaced on virus research bulletin boards, which also indicated multiple cases in Europe.

The identification of Deltacron led to widespread news coverage and much debate on social media, but experts have questioned the findings, particularly those in Cyprus.

Dr. Jeffrey Barrett, Director of the COVID-19 Genomics Initiative at the Wellcome Sanger Institute in the United Kingdom, believes the findings are due to a lab error.

“This is almost certainly not a biological recombinant of the Delta and Omicron lineages,” he says. “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.”

Writing on Twitter, Dr. Tom Peacock, a virologist at Imperial College London in the U.K, also dismissed the findings, saying that “[t]he Cypriot ‘Deltacron’ sequences reported by several large media outlets look to be quite clearly contamination.”

In a separate tweet, he nevertheless clarified that this was not due to poor lab practice, stating that it “happens to every sequencing lab occasionally.”

The evolutionary evidence appears to back up their comments. Several experts have stated that if Deltacron was truly a new recombinant variant, samples would cluster on the same branch of SARS-CoV-2’s phylogenetic tree.

However, Deltacron appears randomly on several branches, which experts say is a sure sign of contamination.

However, Dr. Kostrikis defended his findings. He asserted that since Deltacron infection rates were higher in hospitalized patients than in nonhospitalized individuals, the contamination hypothesis was less likely.

In addition, the samples identified as Deltacron were processed in multiple sequencing procedures in more than one country, lessening the likelihood of lab errors, he noted.

The Cyprus team has since reported another 52 cases of Deltacron to the Cyprus Mail. The Cyprus health minister also defended the findings, saying that the groundbreaking research made him “proud of our scientists.”

While many experts have dismissed the claims that Deltacron is a new hybrid variant, others are willing to wait for more evidence.

Speaking to Medical News Today, Dr. William Schaffner, a professor of infectious diseases at the Vanderbilt University Medical Center, Nashville, TN, commented that “[f]urther local epidemiological investigation in Cyprus is warranted to sort this out. The world certainly is watching.”

“Deltacron has attracted a great deal of interest in the COVID scientific community. Whether it is, indeed, a new variant that has emerged as a result of a combination of Delta and Omicron viruses from a simultaneous infection in a human or whether it happened because of a laboratory accident still remains to be determined.”

– Dr. William Schaffner

Whether that evidence will be forthcoming from Cyprus, or elsewhere, is open to question. MNT contacted Dr. Kostrikis but was still awaiting a response when this article went to press.

In the meantime, researchers affiliated with the GISAID Initiative — a database that “promotes the rapid sharing of data from all influenza viruses and the coronavirus causing COVID-19” — have urged renewed caution when it comes to interpreting the data that allegedly indicate the emergence of a new sub-variant of SARS-CoV-2.

“[R]ushing to conclusions on data that have just been made available by labs that find themselves under significant time pressure to generate data in a timely manner is not helpful in any outbreak,” Cheryl Bennett, an official at the GISAID office in Washington, D.C., has told Nature.

Dr. Kostrikis has since commented to Nature that he and his team are planning to submit their data for peer review, noting that they are “in the process of investigating all the crucial views expressed by prominent scientists around the world about [their] recent announcement” regarding the emergence of an alleged new variant.

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