The World Health Organisation has classified a fast-spreading coronavirus strain circulating in the UK and the US as a “variant of interest”.
But it said the strain, known as EG.5 or Eris, did not seem to pose more of a threat to public health than other variants.
With an estimated more than 17 per cent of cases, the variant is now the most prevalent in the US and the second-most prevalent variant in the UK, after Arcturus.
It emerged as hospital admissions spiked amid bad weather and waning immunity in the UK this summer.
Certain areas have suffered a particular increase in cases and hospital admissions over the school holidays.
But this week the government decided free flu jabs and Covid boosters will not be offered to nearly 12 million Britons this winter.
Hospital Covid admissions rose to 1.97 per 100,000 as of 30 July 30, compared with 1.47 per 100,000 the previous week.
Hospitals in southwest England recorded the highest admission rate, with a 104 per cent increase in cases in Devon.
Other Covid hot spots included Surrey, with a 103.3 per cent increase, and Derbyshire, with a 121.4 per cent increase, as well as Cornwall, Somerset, Staffordshire, Darlington and Cumbria.
Prof Christina Pagel, a member of the Independent Sage group, said she believed the UK was definitely starting another wave of Covid, driven by Arcturus and Eris, waning immunity and poor weather.
She said: “The wet weather over the last few weeks probably isn’t helping either as it keeps people inside.”
The variant could spread more quickly because most people were now over 18 months from their last vaccine and it was also several months their last infection, she added.
Eris, named after the Greek goddess of strife and discord, also has been detected in China, South Korea, Japan and Canada, among other countries.
“Collectively, available evidence does not suggest that EG.5 has additional public health risks relative to the other currently circulating Omicron descendent lineages,” health chiefs said.
A more comprehensive evaluation of the risk posed by EG.5 was needed, they added.
Covid-19 has killed more than 6.9 million people globally, with more than 768 million confirmed cases since the virus emerged. The World Health Organisation declared the outbreak a pandemic in March 2020 and ended the global emergency status for it in May this year.
