As the number of Delta variant cases continues to spread across the UK, the government has warned of a new mutation of the variant which was first identified in Nepal.
Here's everything you need to know about the Nepal variant:
What is the Nepal Covid variant?
The Nepal Covid variant is a mutation of the Delta variant, the official name of the variant first identified in India.
What is the Delta variant?
The Delta variant B16172, also known as VOC-21APR-02, was first detected in India in March.
It is one of three related variants of the virus. The other two variants - called B16171 and B16173 remain classified as "variant under investigation".
The Delta variant remains a "variant of concern" as Public Health England said the variant is now believed to be dominant in the UK.
Early evidence also suggests it may lead to an increased risk of hospital admissions compared with the Kent variant.
A total of 12,431 cases of the Delta variant, have been confirmed in the UK up to June 2, according to Public Health England (PHE), which is up 79% from the previous week’s total of 6,959.
Is the Nepal mutation already in the UK?
Yes. Dr Jeff Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute, has said the K417N mutation - which was first identified in Nepal - has been seen in numerous countries including the UK.
"This Delta+K417N has been seen in numerous countries, including the UK, Portugal, the USA, and India," he said.
He added: "It has also been observed once in Nepal (which does very little sequencing), and 14 times in Japan, of which 13 are samples from airport quarantine from travellers from Nepal."
Is the Nepal variant similar to any others?
Dr Barrett also said the mutation has also been observed in other variants including the one first identified in South Africa.
He said: "This mutation is present in B.1.351 / Beta, and is believed to be part of why that variant is less well neutralised by vaccines.
"Because of this possibility, and because Delta appears more transmissible than Beta, scientists are monitoring it carefully," he added.
Dr Barrett added that because of this possibility and because the Delta variant appears more transmissible than the variant first detected in South Africa, scientists are monitoring it carefully.
What has the UK government said?
When the Transport Secretary Grant Shapps announced Portugal will move from the green list to the amber list, he said the Nepal mutation "caused concern" for the UK government.
Mr Shapps said: "There's a sort of Nepal mutation of the [Delta] Indian variant which has been detected.
"We just don't know the potential for that to be a vaccine defeating mutation and simply don't want to take the risk as we come up to the 21 June and the review of the fourth stage of the unlock."
Why hasn't the World Health Organization (WHO) renamed this variant?
Experts working with the World Health Organization (WHO) developed the labels for variants which are often colloquially named after the places where they are first detected.
On Thursday morning, the WHO said it was "not aware of any new variant of SARS-CoV-2 being detected in Nepal".
The International health agency said: "The confirmed variants in circulation are: Alpha (B.1.1.7), Delta (B.1.617.2) and Kappa (B.1.617.1).
"The predominant variant currently in circulation in Nepal is Delta (B.1.617.2)," the WHO said, referring to three strains by their new Greek alphabet titles.