The conflict in Ukraine has diverted attention from the COVID pandemic, which has not gone away, and in a number of regions was marked by powerful outbreaks. Scientists are worried about the spread of a new variant of the coronavirus known as Deltacron.
As the virus’s compound name suggests, “Deltacron” is a variant of COVID that contains elements of “Delta” and “Omicron” – in other words, it contains genes from both variants, making it a so-called recombinant virus.
“These recombinants occur when more than one variant infects and replicates in the same person in the same cells,” explains Professor Lawrence Young, a virologist at the University of Warwick. “Deltacron is the product of the Delta and Omicron variants circulating in the same population.”
This week, Gisaid, a global community of scientists that shares information about the virus, reported that the first hard evidence for the existence of this variant came from the Institut Pasteur in France.
This variant has been found in several regions of France and appears to have been circulating since the beginning of the year, according to Gisaid. “Genomes with a similar profile have also been identified in Denmark and the Netherlands,” the scientists report.
According to the UK Health Security Agency (UKHSA), there have also been reports of Deltacron being found in the US, and about 30 cases have been found in the UK. The press has reported that the first cases of person-to-person transmission of Deltacron in the UK should be confirmed this week.
Dr. Étienne Simon-Laurier of the Pasteur Institute warned that Delta and Omicron could produce several different recombinant viruses.
“The one we see in France and in Denmark/Netherlands is very similar and could be the same recombinant (with the same parent viruses) that traveled,” he said. But, the scientist added, possible Delta-Omicron recombinants reported in various countries, including the UK and the US, appear to combine different parts of their parent viruses and are therefore different from the Delta-Omicron found in France.
“We may have to find another name to refer to these recombinants, or start adding a number,” Dr. Simon-Laurier said.
How worried should we be? Experts were quick to point out that recombinant variants are not uncommon and that Deltacron is not the first nor the last such case with COVID.
“This happens whenever we are in transition from one dominant variant to another, and is usually a scientific curiosity, but nothing more,” says Dr. Geoffrey Barrett, who previously led the COVID-19 genomics initiative at the Wellcome Trust. Sanger.
However, only a small number of cases of Deltacron have been identified so far, but there is not yet enough data on the severity of this variant or how well the vaccines protect against it.
Soumya Swaminathan, Chief Scientist at the World Health Organization, tweeted on Tuesday: “We know that recombinant events can occur in humans or animals with multiple circulating #SarsCoV2 variants. We need to wait for experiments to determine the properties of this virus. The importance of sequencing, analytics and rapid data sharing in the fight against this pandemic.”
Professor Lawrence Young agrees. “We need to monitor the behavior of this recombinant in terms of its transmissibility and its ability to evade vaccine-induced immune defenses,” he says. “It also reinforces the need to maintain genetic surveillance. As the virus continues to circulate, especially among under-vaccinated populations and in people whose vaccine-induced immunity wanes, we are likely to see more variants, including those created by recombination.”
But this does not mean that this option is cause for panic: according to the UKHSA, this option does not yet cause concern in terms of growth rates.
“It has been seen a small number of times in the UK and still seems to be very rare worldwide, only a few dozen sequences among millions of Omicrons,” says Dr Geoffrey Barrett. “So I don’t think there’s anything to worry about at the moment, although I’m sure it will continue to be monitored.”
Previous waves of Delta and Omicron, as well as vaccinations, mean there is likely to be at least some protection against this option.