Another new coronavirus variant
has been identified with Delta and Omicron elements.
What is Deltacron?
As the portmanteau suggests, Deltacron is a Covid variant that
contains elements of Delta and Omicron – in other words, it contains genes from
both variants, making it what is known as a recombinant virus.
Prof Lawrence Young, a virologist at the University of Warwick,
says, "These recombinants arise when more than one variant infects and
replicates in the same person, in the same cells." "Deltacron is a
product of both the Delta and Omicron variants circulating in the same
population."
The Pasteur Institute in France shared the first solid evidence
for this variant this week on Gisaid, a global community of scientists that
shares virus information.
Where has this variant been found?
According to Gisaid, the variant has been found in several regions
of France and has been circulating since the start of the year. "Genomes
with a similar profile have also been discovered in Denmark and the
Netherlands," says Gisaid.
Deltacron has also been found in the United States, with roughly
30 cases reported in the United Kingdom, according to the UK Health Security
Agency (UKHSA). The i newspaper said the first cases of person-to-person
transmission of Deltacron in the UK were expected to be confirmed this week.
Dr. Etienne Simon-Loriere of the Institut Pasteur cautioned that
there could be several different recombinant viruses formed from Delta and
Omicron.
"The one we see in France and Denmark/Netherlands look super
similar and might be the same recombinant (with the same parental viruses) that
have traveled," he said. But, he added, the possible Delta-Omicron
recombinants reported in countries including the UK and US appear to combine
different pieces of their parental viruses and therefore differ from the
Deltacron seen in France.
"We might need to find a different name to indicate these
recombinant or start adding a number," he said.
How worried should we be?
Experts have stressed that recombinant variants are not uncommon
and that Deltacron is not the first and will not be the last to occur for
Covid.
"This happens whenever we are in the switchover period from
one dominant variant to another and is usually a scientific curiosity but not
much more than that," says Dr. Jeffrey Barrett. He formerly led the
Covid-19 genomics initiative at the Wellcome Trust Sanger Institute.
With only a small number of cases of Deltacron so far identified,
there is not yet enough data about the severity of the variant or how well
vaccines protect against it.
"We have known that recombinant events can occur, in humans
or animals, with multiple circulating variants of #SarsCoV2," Soumya
Swaminathan, the World Health Organization's chief scientist, tweeted on
Tuesday. We need to wait for experiments to determine the properties of this
virus. Importance of sequencing, analytics, and rapid data sharing as we deal
with this pandemic."
Young agrees. "We need to keep an eye on the behavior of this
recombinant in terms of its transmissibility and its ability to escape
vaccine-induced immune protection," he says. "This also serves to
reinforce the need to maintain genetic surveillance. As the virus circulates,
particularly in under-vaccinated populations and in people whose
vaccine-induced immunity is decaying, we are very likely to see more variants
including those generated through recombination."
But that does not mean the variant is a reason to panic: according
to the UKHSA, the variant is not exhibiting a growth rate of concern.
"It has been seen in the UK a few times, and so far seems to
be very rare anywhere in the world, with only a few dozen sequences among the
millions of Omicrons," says Barrett. "So I don't think it's anything
to be concerned about, though I'm sure it will continue to be monitored."
Previous waves of Delta and Omicron and vaccinations mean there is likely to be at least some protection against this variant.