Public Health England has been tracking the spread of the B.1.617.2 mutation – which originated in India – by testing positive Covid-19 cases across the country for an "S-gene".
The gene is not present in the dominant Kent variant, which was responsible for a surge in cases over the winter, but is present in other variants of concern, including those from India.
Scientists have determined that the vast majority of the S-gene specimens identified across England in May are the Indian variant.
PHE identified one positive case of the S-gene in South Tyneside between May 2-14.
Tom Hall, Director of Public health at South Tyneside Council, said: “The data refers to a historic case which was identified, contact traced and isolated. There is no cause for residents to be alarmed.
"The current public health advice still stands, we must all do everything we can to mitigate the spread of the virus following the essential hands, face, space fresh air guidance. Residents are encouraged to make use of free twice weekly home testing and must self-isolate if a positive result is given.
"Of course anyone experiencing symptoms should self-isolate and book a PCR test immediately.
"When invited to take up the vaccine, everyone is encouraged to come forward and take both doses to help protect themselves and those around them.
"We’ve come so far in the fight against coronavirus and by continuing to be vigilant and considerate to others we can get through the other side.”
The majority of areas in England have reported at least one case of S-gene specimens.
But the North East as a whole is one of the regions least affected by the variant.
The data shows 6,729 S-gene positive cases were recorded in England between the start of March and May 11 – up from 4,363 by May 5.
Of these, 47 (1%) were in the North East – the smallest proportion of England's nine regions, and well behind the North West, where there are almost 3,000.
PHE analysis suggests that of a national sample of 1,192 positive S-gene specimens, 93% were found to be the B.1.617.2 Indian mutation.
The data comes as a separate PHE study found both the Pfizer and AstraZeneca vaccines were highly effective against the Indian strain after a second dose.
However, the same study found they were only 33% effective three weeks after the first dose.
The efficacy of the vaccines against the new variants is seen as a major obstacle blocking the next stage of the roadmap, but the chief executive of the UK Health Security Agency said the possibility of restrictions being eased on June 21 was “looking good”.
However, Dr Jenny Harries urged the public to be cautious to avoid another lockdown, warning that the new Indian variant has become the “dominant strain” in some parts of the country.
She told BBC One’s The Andrew Marr Show: “It’s looking good if people are continuing to observe all of the safety signals, so we should not stop doing what we’re doing, particularly in areas where we have that variant of concern."
From June 21 at the earliest, nightclubs are due to reopen and restrictions on large events such as festivals are to be lifted, as are restrictions on the number of people at weddings.
However, Professor Adam Finn, a member of the Government’s Joint Committee on Vaccination and Immunisation, believes there may be “adjustment” to the lifting of restrictions.