A new coronavirus variant detected in Yorkshire which contains three concerning mutations is being investigated by Public Health England (PHE).
The AV.1 variant, which has caused at least 49 cases of infection in Yorkshire and the Humber region, was first detected in April.
The “Yorkshire variant” has been labelled a "triple mutant" as it carries three mutations associated with other variants of concern: E484K, which is also found in the South African variant and can in theory lessen the effect of vaccines; N439K which is also associated with impacting immunity; and P681H, which is in the Kent variant and linked to greater transmissibility.
While new variants emerge all the time - such as the Indian variant which has surged in the UK over the past week - government sources said this particular one carries other features associated with variants of concern.
Dr Kev Smith, from PHE, said scientists had been watching and sequencing the variant since the "strange combination of mutations" were spotted a few weeks ago.
"So far the people that we have identified are not particularly infectious, they're not really getting more sick than other cases of coronavirus and we're not seeing anything particularly worrying about it," he said.
"At the moment, we don't think it's more infectious than the other coronaviruses that we are seeing around."
Watch: COVID 'clusters' across the country as Indian variant cases rise
When was it found?
PHE has been aware of the new strain since April.
Greg Fell, director of public health in Sheffield, said his team had been monitoring the variant – referred to as VUI-21MAY-01 or AV.1 – after PHE announced 49 cases were identified, mostly in Yorkshire and the Humber region.
He said: “We work very closely with NHS Test and Trace and Public Health England on these matters to make sure all appropriate public health interventions are being carried out, including any additional contact tracing and targeted testing.
“Where cases have been identified, additional follow-up of cases, testing of contacts and targeted case finding will be used to limit the spread of variants."
Where has it been found?
Alongside the 49 cases of clustered in the Yorkshire and Humber region, it has also been detected in Greece and Chad.
Why are people monitoring it?
The Yorkshire variant appears to have properties of concern that could in theory lead to reduced effectiveness of vaccines, and higher transmissibility. This has not yet been proven but is being studied.
Why are some experts worried?
Professor Francois Balloux of University College London said the Yorkshire lineage might have some Variant of Concern potential based on its "complement of mutations".
He went on to say that as variants develop they naturally evolve to increase in transmissibility. He added that this 'evolution' of the virus could lead to the possibility of variants emerging that could reinfect people who have been vaccinated.
"Eventually, there will likely be an emergence of 'immune escape' lineages that can readily reinfect hosts who have been previously infected or vaccinated," he wrote.
"Though, the hosts should still benefit from their cellular immunity reducing symptom severity."
Prof Balloux warned that booster vaccinations could be required as the virus evolves.
He said: "Regularly updated vaccines and boosters may be required at least for the more vulnerable in society to minimise the burden. Though, given the extraordinary surveillance in place and our ability to update vaccines promptly, this should be manageable."
What has the government said?
The Prime Minister’s official spokesman highlighted that there have been a number of variants throughout the pandemic and that there will continue to be so.
"There are three mutations of the B1617 strain, as I think has been discussed previously, but as we do with all variants where we spot and identify them through our genomic sequencing programme," the spokesperson said.
"We will continue to monitor them and we will designate them as variants under investigation, and then variants of concern if we deem them to be of greater risk.
“But again, as you’ve seen throughout the pandemic, that’s what we’ve done and we won’t hesitate to put in measures that we think are necessary to try and tackle the transmission of any variants.”
Asked whether the discovery of the new variant would have an impact on the next stage of restrictions lifting on June 21, the spokesman said the five-week gap between measures relaxing would allow the variant to be monitored.
He added: “As the Prime Minister has said, we will continue to look at all the statistical evidence and data, and we’ll set out our plans as soon as the data allows.”
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