Indian or South African variants could overtake to become dominant in the UK, scientists have warned.
Experts responsible for monitoring for mutant Covid-19 in Britain have discovered that the Indian variant can spread “at least” as well as the Kent variant currently dominant.
Known officially as B.1.617.2, cases of the Indian variant in the UK have grown from 202 to 502 in a week, mostly in Bolton and London.
Almost half are related to travel from abroad.
The Covid-19 Genomics UK Consortium (COG-UK) said there is a “possibility” it could take over in Britain but that vaccines would drastically reduce severe cases and deaths.
COG-UK member Prof Ravi Gupta, of Cambridge University, said: “Yes there is a possibility [it could become dominant].
“We have very low transmission in the UK so there is an opening for a virus that is better adapted to vaccinated people to start transmitting.
“It won’t cause severe disease in the majority of people or death. But it could become the thing that circulates. So could the South African variant.”
Britain has one of the best genetic sequencing groups in the world able to quickly identify new Covid-19 variants and how dangerous they are.
It comes as the world’s second-most populous country is coming under pressure to completely lockdown as the Indian variant wreaks havoc.
Prime Minister Narendra Modi is facing growing calls for draconian restrictions after India suffered 2.7 million confirmed infections and 3,754 deaths.
Hospitals are running out of oxygen and beds while morgues and crematoria are full.
Public Health England last week declared the Indian variant a “variant of concern” on the back of its analysis.
Many more variants could be circulating unidentified in parts of the world unable to carry out genetic sequencing of viral samples.
Prof Sharon Peacock, director of COG-UK, said: “The truth is we don’t know at the moment what the balance will be between the Kent variant and new variants coming in.
"Looking at the overall landscape I'm still very delighted that vaccines are working and disease rates are falling so we're in a very good position.
"As scientists we just have to keep our eye on this so that we just maintain that trajectory."
The experts warned that despite vaccine protection there will be a sizable minority of the population who remain vulnerable to incoming Covid variants.
