New Delta variant spreading in the UK called AY.4.2 is being watched by scientists and public health officials
Health officials are keeping a close eye on a new variant of coronavirus said to be now spreading quickly in the UK.
Described as a descendent of the original Delta strain - the newly designated AY.4.2 is now being rapidly assessed by public health experts to assess what danger, if any, it may pose. Here's what we know so far:
What is AY.4.2?
AY.4.2 is a newly designated variant of coronavirus that public health officials say is 'expanding' in the UK, particularly in England. It was first identified in July this year and cases have been steadily increasing since then.
The Delta variant is currently the UK's most dominant strain of Covid19 - accounting for the vast majority of positive swabs that have been genetically sequenced.
It is believed that AY.4.2 is essentially an offshoot of the original variant - a Delta sublineage - and scientists are now looking at whether it is likely to behave in the same way as the main strain already in circulation or whether anything in its genetic make up gives further cause for concern.
Is it spreading?
The sub-variant is thought to be accounting for almost 10% of cases in the UK, according to the last available data, but numbers are said to be consistently increasing particularly in recent weeks. There is also a suggestion that, judging by the numbers emerging, that it is likely to be between 10% and 15% more transmissible than the original Delta strain.
However AY.4.2 is also not to blame for the current rise in cases in the UK, particularly as for now it only makes up less than 10% of total numbers. But if it can spread quicker and easier than other strains in circulation, it in time may obviously lead to more significant outbreaks and contribute to already rapidly increasing case numbers.
What is the cause for concern?
There are hundreds of different types - or variants of Covid - which are circulating around the world. And as viruses frequently mutate it is no surprise that over time new strains develop. Some new variants can be worrying, others less so, and it is down to scientists to establish which ones need watching more closely.
What scientists need to be sure about is whether AY.4.2, apart from possibly spreading more easily, poses anyone who catches it a greater risk of severe illness or whether its genetic make up has the potential to evade vaccines. This is the same approach for any new variant that emerges worldwide. A full assessment of this Delta strain, says Public Health England, is currently underway.
AY.4.2 is not the only subvariant from the Delta strain to emerge, there have been a number of others during the course of the pandemic and others that are and have been watched closely by health experts, but at this moment in time it is proving to be the most prominent and cases of it are on the rise.
How easily passed on any variant might be, could also have an impact on the R number in the UK which suggests how quickly or slowly the outbreak is travelling.
What about in the rest of the world?
Outside of the UK AY4.2 is said to be quite rare but further spread or an increase in cases could lead the World Health Organisation to declare the strain a variant of interest or concern.
One case has been identified in Israel this week in a patient thought to have been travelling outside of the country, there are 'isolated' cases in Russia and a small handful reportedly in the US. The UK has the vast majority of worldwide cases so it will be down to scientists in posession of the data, to learn what they can about it.
But new variants and any subsequent rise in cases can pose other problems too, even if it turns out to be no more deadly. On Wednesday evening, shortly after the government's 5pm press conference, Morocco announced it was banning all flights arriving from the UK. It is closing its borders to the UK, alongside Germany and the Netherlands, because of the 'pandemic situation'.