Although the World Health Organisation (WHO) declared the end of COVID-19 as a global health emergency in May, the virus is still widespread - and mutating.

While the EG.5 and EG.5.1 now makes up one in seven cases in the UK, a new heavily-mutated version of Omicron could be another cause for concern.

So far the latest BA.2 "sub-lineage" (coined BA.6 or 'Pi') has only been sequenced a handful of times in Denmark and Israel - but the early differences showing up could mean it has the potential to cause a fresh wave of infections.

Here's what we know so far.

Where has it been found - and when did it emerge?

The new variant is a mutation of the first sub-variant of Omicron known as BA.2 that emerged in November 2021.

It has only been sequenced three times, twice in Denmark and once in Israel, having first been identified in Denmark on 24 July.

This doesn't mean there aren't more cases, but it has only appeared on a small number of occasions when scientists have screened virus samples for their genetic make-up.

Some are predicting it may already be in the UK and the US.

At such an early stage, it hasn't been given an official name - although some are referring to it as BA.6 or the 'Pi' variant.

How is it different?

Compared to the original BA.2, the new variant has 33 mutations of the spike protein - the membranes on the outside of the virus that allow it to enter and infect human cells.

These are the things that change as the virus grows and evolves - and can help it spread faster or evade immunity provided by either natural infection or vaccines.

Professor Andrew Easton, a virologist at the University of Warwick, explains: "Some mutations are damaging to the virus, some are neutral so don't have any impact at all, and others may benefit the virus.

"Those benefits could give it an advantage in growing more effectively or rapidly - or allowing it to evade the immunity that already exists in the community."

Because of the large number of mutations, it's being referred to as a 'saltation' - a large mutational change from one generation of virus to the next, which was used to describe Omicron when it first emerged.

Should we be worried?

With only three cases sequenced, it is "way too early to say what impact this new variant will have", according to Ryan Hisner, an online COVID genomic sequencing tracker on X, formerly known as Twitter.

Professor Christina Pagel, an expert in operational research at UCL, adds that although it is "very, very early days" it has "a lot of new mutations that make it very different to previous Omicron strains".

She says this could mean it is "potentially more able to cause a big wave" because it could outstrip the immunity we already have.

But Professor Easton says although there are a considerable number of mutations - you need far more cases to see if a pattern of rapid spread, immune escape or more severe disease emerges.

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"In order to assess all these things it's a numbers game," he tells Sky News.

"It's not something we can easily predict - but what we can say is that these mutations may affect the virus's ability to escape immunity - or spread faster."

For example a variant labelled BS.1.1 appeared with significant mutations in 2022 but "had little impact globally".

The most important thing for now, Professor Easton stresses, is surveillance.

"The earlier you're able to pick up a variant of concern the earlier you can intervene in terms of alerting people to the risks - or altering vaccines.

"Because the faster you react the lesser the impact on people."