The UK Health Security Agency is officially tracking a mutant hybrid variant of Covid after cases were found in the UK.
The strain has been named Deltacron as it appears to be a combination of the Delta and Omicron variants.
Experts say it has evolved in patients who caught both variants at the same time, but it is unclear whether the UK cases developed here or were contracted abroad.
UKHSA officials do not yet know how infectious Deltacron is, or how severe the symptoms can be.
The agency has not revealed how many times it has been found in the UK, reports the Mail.
Professor Paul Hunter, an infectious disease expert at the University of East Anglia, told MailOnline: “If both Delta and Omicron are falling then, in theory, this [variant] should struggle to take off.”
Recombinant variants are rare but have occurred three times before in the Covid pandemic – infecting hundreds of people.
Cases of Deltacron found in Cyprus last month were originally dismissed as a mistake.
A UKHSA source told MailOnline: “We monitor everything as a matter of course, but we are not particularly anxious about this variant.”
Deltacron has been included in the UKHSA’s latest weekly variant surveillance report.