What is Deltacron?
As the purse suggests, Deltacron is a variant of Covid that contains elements of Delta and Omicron – in other words, it contains the genes of 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,” says Prof Lawrence Young, a virologist at the University of Warwick. “Deltacron is the product of Delta and Omicron variants circulating in the same population.”
Gisaid, a global community of scientists that shares information about the virus, reported this week that the first hard evidence for this variant came from the Institut Pasteur in France.
Where was this variant found?
Gisaid says this variant has been found in several regions of France and appears to have been circulating since the beginning of the year. “Genomes with a similar profile have also been identified in Denmark and the Netherlands,” Gisaid says.
According to the UK Health Safety 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 i newspaper reported that the first cases of Deltacron person-to-person transmission in the UK should be confirmed this week.
Dr. Etienne Simon-Laurier of the Pasteur Institute warned that there could be several different recombinant viruses formed from delta and omicrons.
“The one we see in France and in Denmark/Netherlands looks very similar and could be the same recombinant (with the same parent viruses) that travelled,” he said. But, he added, possible Delta-Omicron recombinants reported in countries including the UK and the US appear to combine different parts of their parent viruses and are therefore different from the Deltacron found in France.
“We may have to find another name to refer to these recombinants or start adding a number,” he said.
How worried should we be?
Experts were quick to point out that recombinant variants are not uncommon and that Deltacron is neither the first nor the last case of Covid.
“This happens whenever we are in a period of 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. . institute.
However, only a small number of cases of deltacron have been identified so far, but there is not enough data yet on the severity of this variant or how well 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.”
Yang 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 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 Barrett. “So I don’t think it’s worth worrying about at the moment, although I’m sure it will continue to be monitored.”
The previous waves of Delta and Omicron, as well as vaccinations, mean there is likely to be at least some protection against this option.