People have started catching a new Covid variant that could soon take off and become the dominant type, BBC reports citing scientists.
Identified in Germany, in June, cases of the XEC variant have since emerged in the UK, US, Denmark and several other countries, say users on X, formerly known as Twitter.
It has some new mutations that might help it spread this autumn, although vaccines should still help prevent severe cases, experts say.
For those more likely to become seriously ill from Covid, the NHS offers a free booster shot.
The vaccines have been updated to better match recent variants, although not XEC, which has emerged from earlier Omicron subvariants.
Prof Francois Balloux, Director of the Genetics Institute at University College London, told BBC News that although XEC has a "slight transmission advantage" over other recent Covid variants, vaccines should still offer good protection.
He says it is possible XEC will become the dominant subvariant over the winter though.
Director of the Scripps Research Translational Institute, in California, Eric Topol says XEC is "just getting started".
"And that's going to take many weeks, a couple months, before it really takes hold and starts to cause a wave," he told the LA Times.
"XEC is definitely taking charge.
"That does appear to be the next variant.
"But it's months off from getting into high levels."
Symptoms are thought to be the same cold or flu-like ones as before: a high temperature, aches, tiredness, and a cough or sore throat.
Most people feel better within a few weeks of Covid but it can take longer to recover.
There has been "strong growth" of XEC in Denmark and Germany, Covid data analyst Mike Honey says on X.
There is far less routine testing than before, making it difficult to know how much Covid might be around.
More about:
