The South African variant of coronavirus has been found in a south London borough, with door-to-door testing being rolled out in affected postcodes.
Mitcham, the borough of Merton, is one of eight areas in England where the strain has been identifed, the others being Haringey and Ealing, as well as Hertfordshire, Surrey, Kent, Walsall, Sefton, the Guardian reports.
Experts are seeking to urgently test 80,000 people due to fears there may pockets of spread in local communities.
So far, just over 100 cases of the South African strain have been identified to date across the UK, but this is the first signal of wider community spread.
Residents within the affected areas will be asked to carry out a test even if they have no symptoms.
Some of the vaccines in use and currently going through approval have shown some effectiveness against the variant.
People will be urged to agree to testing, whether they have symptoms or not.
The South African variant is thought to be as transmissible as the variant that was first identified in Kent but there is no evidence as yet that it causes more severe disease.
It is not yet known whether the Oxford University/AstraZeneca vaccine will be effective against the variant, although other vaccines have shown promising results.
Experts advising the Government said they did not think the current vaccines would need to be tweaked to deal with any spread of the South African variant.
To date, 105 cases of the South African variant have been identified in the UK since December 22 but all of those had links to travel.
Experts believe the 11 new cases may also have second or third generation links to travel but detailed investigations have not identified any such links.
Health and Social Care Secretary Matt Hancock said: “It is vital that we do all we can to stop transmission of this variant and I strongly urge everyone in these areas to get tested, whether you have symptoms or not.
“The best way to stop the spread of the virus – including new variants – is to stay at home and follow the restrictions in place. Until more people are vaccinated this is the only way we will control the spread of the virus.
“The UK is a global leader in Covid-19 genomics and, because of this, we have been able to identify new strains of the virus and take decisive action.
“We continue to closely monitor new variants, here and around the world, and in addition to our already extensive testing service, we are making surge-testing capacity available to affected areas.”
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