A new Covid variant has emerged which is set to sweep across Europe and the US and potentially become the dominant type, according to scientists.
The XEC variant was first identified by German scientists but cases have been confirmed in the UK, US, Denmark and several other countries.
It has some new mutations that could make it the dominant strain by the autumn after first being spotted in June.
However, current vaccines should ward off serious illness, experts have said.
The NHS offers a free booster shot for vulnerable groups.
Prof Francois Balloux, Director of the Genetics Institute at University College London, said that although XEC has a "slight transmission advantage" over other recent Covid variants, vaccines should still offer good protection.
He told the BBC it is possible XEC will become the dominant subvariant over the winter though.
Director of the Scripps Research Translational Institute, in California, Eric Topol sid XEC is "just getting started".
He told the LA Times: "And that's going to take many weeks, a couple months, before it really takes hold and starts to cause a wave.
"XEC is definitely taking charge.
"That does appear to be the next variant.
"But it's months off from getting into high levels."
The UK Health Security Agency (UKHSA) has said it is normal for viruses to mutate and change.
UKHSA Deputy Director Dr Gayatri Amirthalingam said: “It is normal and expected for viruses to genetically change over time.
“UKHSA continues to monitor all available information relating to emerging Covid variants in the UK and internationally, and to publish our data regularly.
“Vaccination provides the best protection against serious illness from COVID-19, and we urge those who are contacted by the NHS to come forward to receive their autumn vaccine.”
