Public Health England said cases of the variant, referred to as VUI-202102/04, were first identified on February 15 through genomic horizon scanning.
The variant, which is understood to have originated in the UK, was designated a “variant under investigation” (VUI) on February 24.
Variants of Covid-19 can be identified as VUIs or “variants of concern” (VOCs).
But how worried should we be about the news strain of Covid-19?
What is the new Covid-19 variant?
The latest identified variant is known as B.1.1.318, or VUI-202102/04.
Scientists contains the E484K mutation, which is found in two other VUIs present in the UK, but it does not feature the N501Y mutation that is present in all VOCs, PHE said.
As of March 5 scientists have identified 16 cases of the new strain.
What is the E484K mutation?
The E484K mutation has been shown to reduce the effectiveness of vaccines in preventing people contracting Covid-19.
However, public health experts believe current vaccines will still be effective against strains with the mutation, although at a lower level, and are good at preventing severe disease.
Why do viruses mutate?
All viruses naturally mutate as they spread through a population, and this coronavirus Sars-CoV-2 has undergone one or two changes a month since the start of the pandemic.
In fact, it has changed at a slow pace compared to other viruses, like seasonal flu, which mutates at a fast rate so that a new vaccine has to be introduced every year.
It is an RNA virus, like the flu and measles, and these types of viruses are more prone to mutations than DNA viruses, such as herpes and smallpox.
Mutations usually happen by chance, and don’t have much impact on the properties of a virus - the World Health Organisation (WHO) said these changes are “natural and expected”.
Often, they can lead to a weaker version of the virus, or the changes could be so small that there’s no difference in its behaviour.
However, sometimes viruses can mutate in a way that helps the infection to spread.
More worrying mutations are when the proteins on the surface of the virus are changed so it can evade the immune system - or if so many changes have been made that it is now very different to the original variant.
What are the VUIs and VOCs being tracked in the UK?
The findings mean there are now four VUIs and four VOCs being tracked by scientists in the UK.
Other VUIs include one from Brazil, known as P2, which has had 43 probable or confirmed cases identified in the UK, but is not causing scientists serious concern.
PHE said that, as of Wednesday, a total of 26 cases of the P2 variant had been found in England where no travel links could be established.
Two further VUIs – dubbed A.23.1 with E484K and B.1.525 – have seen 78 and 86 probable or confirmed UK cases detected respectively.