What is Deltacron and Should You Be Worried? Chicago's Top Doctor Explains

Johns Hopkins Lab Testing Omicron Variant (1)

With reports surfacing of a so-called "deltacron" COVID mutation that combines both the delta and omicron variants come questions over whether it is real and what it could mean.

Chicago's top doctor was asked that question Tuesday during a COVID-related press conference, where she said variants are likely to continue developing during the pandemic, but "deltacron" is "not a formal word."

"It's a word that people are using. I think it's reflecting a fear that we're not done with variants, and I see no reason to think we are done with variants, just to be really clear about that," Arwady said. "The way people are using that is this concern [that] already omicron has almost all the characteristics of delta and it has most of the same genetic changes that delta had. But it's this idea of sort of pulling together some of what was worse with delta with some of what is worse with omicron. And, you know, there have been some individual cases where we've seen some additional genetic patterns."

Bloomberg News reported on Saturday that a researcher in Cyprus had discovered a strain of the coronavirus that combines the delta and omicron variant.

Leondios Kostrikis, professor of biological sciences at the University of Cyprus, called the strain "deltacron," because of its omicron-like genetic signatures within the delta genomes, Bloomberg said.

So far, Kostrikis and his team have found 25 cases of the virus, according to the report. It's still too early to tell whether there are more cases of the strain or what impacts it could have.

But some experts have expressed doubts about the findings.

A World Health Organization official tweeted Sunday that "deltacron" is "not real" and "is likely due to sequencing artifact."

Dr. Krutika Kuppalli wrote that there was likely to have been a "lab contamination of Omicron fragments in a Delta specimen."

"Let's not merge of names of infectious diseases and leave it to celebrity couples," she said in a later tweet.

CNBC reported another high-profile scientist, Dr. Boghuma Kabisen Titanji, an infectious diseases expert at Emory University in Atlanta, advised a cautionary approach, tweeting Sunday that "On the #deltacron story, just because I have been asked about it many times in the last 24h, please interpret with caution. The information currently available is pointing to contamination of a sample as opposed to true recombination of #delta and #omicron variants."

She also noted, however, that a possible mixing of the genetic material belonging to the delta and omicron variants is possible.

"Recombination can occur in coronaviruses," she wrote. "The enzyme that replicates their genome has a tendency to slip-off the RNA strand it is copying and then rejoining where it left off. With #delta and #omicron both in circulation, dual infection with both variants increases this concern."

The scientist who reported the discovery told Bloomberg Sunday the findings were not the result of a "technical error."

Arwady said additional variants are reported frequently, but stressed there is a process for classifying them. The potential "deltacron" cases are being monitored, but she said it is not yet concerning and has not been labeled a variant of interest or concern.

Omicron and delta variants are currently classified as variants of concern.

"Until it's sort of a variant of interest, I'm not that interested, frankly, and until it's a variant of concern I'm not that concerned," Arwady said. "Please know that here in Chicago, we have used funding from the federal government to significantly build our ability to watch for variants here. ... We see anything of interest or concern, here in Chicago or anywhere in the world, we will absolutely let you know. But really, right now, my worry is omicron."

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