Health chiefs will test staff and pupils at a Northamptonshire school after confirming cases of a highly-transmissable Indian strain of Covid-19.
However, they say widespread surge testing is not required following the discovery of six cases.
Similar cases are cropping up across the UK with mass testing in some affected areas.
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But Public Health Northamptonshire insists further testing is only needed "as a precautionary measure" at one county school and the cases do not appear to be linked to international travel.
Lucy Wightman, the county's Public Health Director, added: "Public Health England notified us on Tuesday that it had identified six cases of an Indian variant in Northamptonshire which do not appear to be linked to international travel but are part of a wider national cluster.
"PHE has already been in touch with the individuals concerned and their contacts.
“Targeted testing will be taking place in a county school community as a precautionary measure.
“There is currently no evidence that this variant causes more severe illness or increased risk of mortality.
"This reminds us that the virus is still out there. It's our job to limit transmission and the main route of that in Northamptonshire is through household mixing.
"So although restrictions are easing, it is imperative that we continue to abide by the guidelines and follow the rules."
The government's Scientific Advisory Group for Emergencies (Sage) is reportedly due to hold an emergency meeting today to discuss the Indian variant of concern and Boris Johnson's roadmap out of lockdown.
Scientists previously revealed a high proportion of cases of the Indian variant — labelled B.1.617.2 — in a tiny batch Covid-19 positive tests in South Northamptonshire
Bedford, Bolton and Blackburn with Darwen were also identified as UK hotspots for the Indian variant in the week to April 24 according to the official data from the Wellcome Sanger Institute, one of the UK's biggest trackers of variants.
That confirmed a report from Public Health England last week which said there are already early signs the Indian variant is overtaking that which started in Kent.
On Thursday, leaked Public Health England documents seen by the Guardian showed that 48 clusters of B.1.617.2 had been identified, including those linked to secondary schools, care homes and religious gatherings.
Public Health England launched surge testing in Bolton to root out cases of the B.1.617.2 variant.
Rising numbers of cases involving the Indian variant are worrying government ministers because little is known about how effective vaccines are at combating infections.
Boris Johnson told Parliament on Wednesday that the variant was "of increasing concern," warning a strain that could slip past vaccines would have "potential to cause even greater suffering than we endured in January."
Early lab trials suggest current jabs will still protect against the Indian variants but there are concerns among Sage members that a faster rate of spread could lead to a bigger outbreak once Covid-19 restrictions are relaxed from Monday.
Andrew Hayward, Sage member and director of the UCL Institute of Epidemiology and Health Care, told the Guardian: “We know that the vaccine is very effective against the Kent strain … but we also know that the vaccine is less effective at protecting against the variant originating in South Africa.
"For the variants arising in India, we have no real-world data and relatively little laboratory data to assess whether it is likely to evade immunity.”
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