A new Covid variant found in the UK is more transmissible than previous strains - but it's still too early to know just how contagious it is, health experts have warned.
The UK Health Security Agency (UKHSA) said it was looking at the XE variant, which is a mutation of the BA.1 and BA.2 Omicron strains.
It is what's known as a "recombinant" - meaning it has been formed from at least two other viral sources.
Experts at the UKHSA say it's too early to know whether it is more transmissible than previous strains like Delta and Omicron.
The body said that 637 cases of XE had been detected in England as of March 22.
That would make it only a fraction of the tens of thousands of total cases being reported each day at the moment, The Independent has reported.
The UKHSA said that initial growth rates for XE were not much different from BA.2, Wales Online reports.
However, more recent data, up to March 16, showed a rate of nearly 10% above BA.2, which has been called 'Stealth' Omicron.
It said that "as this estimate has not remained consistent as new data have been added, it cannot yet be interpreted as an estimate of growth advantage for the recombinant".
"Numbers were too small for the XE recombinant to be analysed by region," the UKHSA said.
Professor Susan Hopkins, the UKHSA's chief medical advisor transition lead, said that recombinant variants were not uncommon.
She added that they usually died off quickly.
“This particular recombinant, XE, has shown a variable growth rate and we cannot yet confirm whether it has a true growth advantage," Ms Hopkins told The Sun.
“So far there is not enough evidence to draw conclusions about transmissibility, severity or vaccine effectiveness.”
With no legal restrictions now in place in England and the requirements to self-isolate removed, recent weeks have seen record numbers of people catching Covid.
The Office for National Statistics said one in every 13 people - or 4.9million - had the virus in the week ending March 26, up from 4.3million in the previous week.
Just days ago the Government's Chief Scientific Adviser, Sir Patrick Vallance, warned the next Covid variant could be worse than Omicron as the virus continues to evolve.
The Government's Chief Scientific Adviser said it is "a mistake" to believe the more Covid evolves, the less serious its mutations will become.
The Omicron variant spread rapidly across the UK in the run-up to Christmas when the R number was estimated to be around 1.3 which meant on average every 10 people infected 13 people.
Sir Patrick said Covid cases may have peaked but there will be more hospitalisations and deaths from this current wave.
Experts believe the vaccines have helped keep the most severe cases at bay.
But Sir Patrick told MPs it was not a "credible" strategy to give people booster jabs every four months.
