Public Health England (PHE) figures show 509 cases of a variant first detected in India, which is known as B1.617.2, were recorded in England by May 5 and 19 of them were detected in Yorkshire and the Humber.
B1.617.2 was classed as a variant of concern earlier this month, as PHE states it is at least as transmissible as the Kent variant but there is “insufficient evidence” to determine whether it is more deadly or the current vaccines are less effective against it.
Speaking earlier today, Prime Minister Boris Johnson said: “It is a variant of concern. We are anxious about it. It has been spreading.
“At the moment, there is a very wide range of scientific opinion about what could happen.
"We want to make sure that we take all the prudential, all the cautious steps now that we could take.
“There are meetings going on today to consider exactly what we need to do. There’s a range of things we could do and we’re ruling nothing out.”
The next step of the government’s easing of lockdown restrictions is planned for May 17, when pubs and restaurants will be able to serve customers inside and up to two households or six people will be allowed to meet indoors.
Another 235 cases of a different Indian variant, known as B.1.617.1, had been detected in England by May 5.
That includes 109 cases in London and 13 in Yorkshire and the Humber.
There is also a third variant that was first detected in India, but only nine cases had been recorded in the UK by May 5 and none of them were in Yorkshire.
Public Health England states the variants are “closely related” but have different genetic profiles and “were designated as separate variants so that we can track them properly”.
Earlier this week, Andy Burnham, Mayor of Greater Manchster, raised concerns about the spread of an Indian variant (B1.617.2) in Bolton, which has the highest infection rate in the country (152 cases per 100,000 people) after 437 new cases were recorded in seven days.
The Labour politician, who was re-elected as mayor earlier this week, asked the Joint Committee on Vaccination and Immunisation (JCVI) for permission to vaccinate everyone over 16 in Greater Manchester.
Vaccines are currently being offered to everyone over the age of 38 in the UK, as well as people who are clinically vulnerable, frontline health and social care workers, unpaid carers and people with a learning disability.
Mr Burnham said a recent spike in cases in Bolton is linked to international travel, particularly from India, but there is also evidence of community transmission.
He also said the data shows the virus has been spreading among “younger people and the working age population” in Bolton, not the over 65s.
“The way to mitigate some of the risks we have is to accelerate vaccination, particularly in the communities most affected by the Indian variant, and it is the Indian variant that’s largely responsible for the increase we’re seen in Bolton,” he said.
“We have been saying for some time there should be a provision to surge vaccine supplies into the areas where the case rates have been highest throughout and where historically there are the greatest health inequalities.
“In many ways we are repeating that request but with renewed urgency, given the effect of what we’re seeing in Bolton.”