Hundreds of people have been affected by a new "stealth variant" of Covid - and experts have warned it could spread even faster than Omicron.
Already 426 cases of the sub-variant of Omicron have been discovered across England to date, reports WalesOnline.
Research so far shows it looks like it is spreading faster than its parent but it is also harder to identify which has led some experts to dub it a "stealth variant".
Go here for the latest coronavirus updates and breaking Covid-19 news
The new strain, Omicron BA.2, was described by UK Health Security Agency (UKHSA) as a “variant under investigation”.
Dr Meera Chand, Covid-19 Incident Director at UKHSA, said: "It is the nature of viruses to evolve and mutate, so it's to be expected that we will continue to see new variants emerge as the pandemic goes on.
"Our continued genomic surveillance allows us to detect them and assess whether they are significant.
"So far there is insufficient evidence to determine whether BA.2 causes more severe illness than Omicron BA.1, but data is limited and UKHSA continues to investigate."
As it is a strain of Omicron the symptoms can be different to the early classic signs of Covid-19 which were the new, continuous cough, a fever and loss of taste or smell.
However, the scientists behind the ZOE Covid symptom app claim many people testing positive for Omicron are logging symptoms more closely associated with the common cold..
For analysis, scientists took the health reports from contributors reporting positive cases in the ZOE Covid Study app in December 2021 as Omicron became dominant and compared them with data from early October when Delta was the dominant variant.
Dr Claire Steves said the top five symptoms in both periods were:
* Runny nose
* Headache
* Fatigue
* Sneezing
* Sore throat
Alongside lower back pain, muscle aches throughout the body have also been reported.
Dr Ryan Noach, the CEO of South Africa-based Discovery Health, also said that the most common early sign was a scratchy throat and most of these symptoms are mild.