Scientists in the UK are looking into four new strains of coronavirus that have been classed as 'variants of concern'.
The latest strain to come under the classification is one identified in Bristol, which has also been found in Manchester.
The Bristol strain has the E484K mutation and is a version of the Kent strain, another 'variant of concern' which is now dominant in the UK.
It has been identified in 21 cases in the UK.
Classifications are determined by the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) – a group of scientists which advise the government.
Out of the four 'variants of concern' identified by the group, only three have been found in the UK.
The variant identified in Bristol, the dominant strain identified in Kent and the variant identified in South Africa are all present in the UK in small numbers, while a 'variant of concern' from Brazil has not yet been identified here.
In addition, NERVTAG is looking at two more new strains which are under investigation.
The first 'variant under investigation' was found in Brazil and has been identified in 24 cases in the UK.
A second 'variant under investigation' was identified in Liverpool and accounts for 55 UK cases.
So what do we know about each 'variant of concern'?
The Kent variant
This variant, also known as B117, was first detected in Kent in September last year.
Experts believe that its spread led to the rapid rise in Covid-19 cases before the second national lockdown was announced in England.
It is now thought to be the dominant variant in the UK and is up to 70 per cent more transmissible than the previous strain.
Data has suggested that the Kent variant may be more deadly, but there is no evidence to indicate existing treatments, such as dexamethasone, will not be effective against it.
All three companies that are producing vaccines for the UK - Pfizer, AstraZeneca and Moderna - have said their vaccines are effective against the strain.
A study has suggested that people infected with this variant are less likely to report a loss of taste and smell as symptoms of coronavirus.
The South Africa variant
This variant was detected in South Africa and first sequenced in the UK in December 2020.
A total of 170 cases of the South African variant have been identified so far in the UK, including 18 that are not linked to travel, according to Dr Susan Hopkins, from Public Health England.
She told a briefing yesterday (February 9): “To date we have identified 170 cases and 18 of these are unlinked to travel, and that means that they neither travelled abroad themselves or (had) a direct contact with an individual that has travelled."
Cases have been found in London, Southport, Kent, Walsall and Lambeth and additional surge testing is being carried out to identify further cases in those areas.
The variant carries the E484K mutation, which experts suggest may be better at evading the human immune response.
Dr Hopkins said the mutation has been "emerging and disappearing over time" in multiple variants since April last year.
The vaccine developed by Pfizer and BioNTech is effective against this variant, according to a study from the US.
A separate study found that the Oxford/AstraZeneca jab was not effective at preventing mild illness caused by the South African strain.
But the jab will protect against deaths and severe disease amid the spread of the South African variant, according to researchers.
England’s deputy chief medical officer, Jonathan Van-Tam, said the South African mutation did not enjoy a “transmissibility advantage” over other variants
He told a press briefing that the South African variant of coronavirus is unlikely to become the dominant strain in the UK in the next few months and that the findings of the study should not be a cause for concern in the UK.
The Bristol variant
The Bristol variant is a version of the Kent variant with an additional mutation.
This variant has the E484K mutation - the same one that is also found in both the South African and Brazilian variants.
It was first detected in Bristol and South Gloucestershire and a handful of other cases have been identified, including in Moss Side, Manchester.
Analysis into this variant is ongoing, and researchers are looking at how vaccines might affect the strain.
The Brazil variant
There are two variants from Brazil - but only one is a 'variant of concern'.
Experts detected the new variant circulating in December in Manaus, north Brazil. No cases of it have been detected in the UK.
The variant was detected in Brazil and in travellers from Brazil to Japan, and contains a unique constellation of lineage defining mutations.
It is not yet known if itcauses more severe Covid-19, but evidence suggests it may be more transmissible.
The Brazilian variant does carry the E484K mutation,raising concerns that vaccines may not be as effective against it.
That is something scientists are currently looking into.
The other variant from Brazil has been detected in the UK, but experts say it is no cause for concern.
