Researchers have issued a warning that the Covid virus's "more contagious" form, known as XEC, is beginning to spread more quickly throughout Europe and may soon overtake other strains.

The head of the Scripps Research Translational Institute in La Jolla, Eric Topol, stated in a post on X on Sunday that "at this juncture, the XEC variant appears to be the most likely one to get legs next."

In August, scientists hypothesized that it might take a few weeks to a few months for this variation to become widely distributed.

“XEC is definitely taking charge,” Dr Topol said.

XEC, a sublineage of the omicron variant, was first reported in Berlin, Germany, in June and is now spreading “quite rapidly” across Europe, North America and Asia, according to Covid data analyst Mike Honey.

Slovenia had high rates of infection with this variant in August as over 10 per cent of Covid case samples from the country contained XEC.

It is a hybrid of previously discovered omicron subvariants – KS.1.1 and KP.3.3 – of the novel coronavirus that causes Covid.

KS.1.1 is a type of what’s commonly called a FLiRT variant.

It is characterised by mutations in the building block molecules phenylalanine (F) altered to leucine (L), and arginine (R) to threonine (T) on the spike protein that the virus uses to attach to human cells.

The second omicron subvariant KP.3.3 belongs to the category FLuQE where the amino acid glutamine (Q) is mutated to glutamic acid (E) on the spike protein, making its binding to human cells more effective.

So far, over 500 samples from 27 countries, including Poland, Norway, Luxembourg, Ukraine, Portugal and China, have been found to contain XEC.

Analysts point to strong growth of the variant in Denmark, Germany, the UK, and the Netherlands.

As the novel coronavirus continues to evolve, data suggests XEC is growing steadily each day with an advantage over previously known subvariants.

Its symptoms are similar to those of previous Covid variants, including fever, sore throat, cough, loss of sense of smell, loss of appetite, and body aches.

But since it is still only a sub-family of the same omicron lineage, experts say keeping up to date with vaccines and booster shots would offer sufficient protection against severe illness and hospitalisation.

The US Centers for Disease Control & Prevention also advises people to practise good hygiene and to take steps for cleaner air.

Researchers have called for monitoring the XEC variant more closely to better understand its symptoms.