However, cases of the variant are now growing both in England and abroad, with the UK Health Security Agency stating it is a ‘variant under investigation’ last week.
Here is everything you need to know about the 'stealth Omicron' variant.
Is it dangerous?
Currently the BA.2 subvariant has not shown any major differences from Omicron in age, vaccination status or risk of hospitalisation.
Early analysis suggests it does however have a faster growth rate than the Omicron strain currently in the UK.
Experts say that, as of now, there are no signs that it is particularly different from the original Omicron variant.
How many cases are there in England?
The Wellcome Sanger Institute analysed 38,000 positive Covid-19 tests taken in the week to January 15 to determine which Covid variant they were.
It found one in 100 samples were now Stealth Omicron across England.
Where did stealth Omicron come from?
It is not yet known where stealth Omicron originated, however the first known cases were found in the Philippines and high numbers are now being reported in Denmark.
As it does not exhibit the usual marker on its spike protein, usually associated with Omicron, it has earned itself the name 'stealth Omicron'.
Both PCR and lateral flow tests are still able to identify the variant.
What are the symptoms?
Symptoms like a sore throat, runny nose, headache, and tiredness could be Covid - especially Omicron or stealth Omicron.
If you are experiencing any symptoms, get tested and isolate until you have your test result.