Boris Johnson’s government had been on track to scrap social distancing measures and remaining restrictions in England on 21 June – the date pencilled in as the end of lockdown.
But the prime minister has warned that the rapid spread of the Indian Covid variant could now pose “serious disruption to our progress”.
So just how worrying is the Indian variant? How effective are the vaccines against it? Could it throw the national vaccination programme off course?
Why makes the Indian variant so threatening?
The new strain, known as B1617.2, has been designated a variant of concern because it is thought to be as much as “50 per cent more transmissible” than the Kent strain, according to the government’s Scientific Advisory Group for emergencies (Sage).
If the variant proves to be 40 to 50 per cent more transmissible, the Sage scientists predict that would it “lead to a much larger peak” of cases, hospitalisations and deaths than previous waves.
Experts think the next few weeks should provide more details about how quickly this particular is sickening people, and whether that might overwhelm hospitals.
Do the vaccines work against the Indian variant?
Scientists think so, but are still waiting for definitive answers. Health secretary Matt Hancock said early results from tests at the University of Oxford University gave “a high degree of confidence” that vaccines do work against B1.617.2.
Early findings from the Oxford laboratory study looking at Pfizer and AstraZeneca vaccines show they suffer only a minor loss of protection - creating enough antibodies to neutralise the variant.
“Urgent experimental data is being generated (for this variant),” said Sharon Peacock of the UK Covid-19 Genomics Consortium.
She noted that vaccines appear to work against other variants to date, but that it is important to determine if one dose is effective or if two are needed.
People queuing for Covid vaccine in variant hotspot of Bolton
What do other countries say about the vaccine and the variant?
Last week Marco Cavaleri, head of vaccines at the European Medicines Agency, said the data appeared “rather reassuring” that vaccines made by Pfizer and Moderna would protect against the variant first seen in India.
He said the agency was still gathering more information on the effectiveness of the shots made by AstraZeneca and Johnson & Johnson and was “pretty confident” those vaccines would also afford people protection from the variant.
Research carried out in the US also found that the Pfizer and Moderna vaccines should be effective against variants first identified in India.
“The vaccine’s antibodies are a little bit weaker against the variants, but not enough that we think it would have much of an effect on the protective ability of the vaccines,” Nathaniel Landau, author of the NYU Grossman School of Medicine-led study , told AFP.
How widespread is the variant in the UK?
The overall number of cases in the UK remain quite small. To date, there have been more than 2,300 cases identified across Britain.
But experts say it’s on track to become the most dominant variant in the country. The growth rate is now “quite high,” according Nick Loman, a professor of microbial genomics at the University of Birmingham.
There has been a 44 per cent increase in the number of areas in England detecting the Indian variant over the past week, according to the Wellcome Sanger Institute.
Vaccinations have been accelerated, especially in hotspot areas like Blackburn and Bolton where high levels of the variant have been detected.
However, there are concerns in government that the vaccination roll-out isn’t moving fast enough to halt the rapid raise of the Indian variant.
Ministers are said to be discussing whether a partial return to England’s tier system is needed to control the spread of the strain. A delay to the 21 June lifting of lockdown is the alternative.