Symptomatic Covid cases in the UK rose by nearly five per cent to more than 80,000 per day last week, according to a surveillance study.
The ZOE symptom-tracking study estimated that 80,483 people fell ill on any given day in the week ending November 27, based on test results from around 650,000 volunteers.
It marked a rise of 4.9 per cent compared to the estimate on the previous week and means one in 61 Britons suffered a symptomatic infection at any given time, King's College London scientists who run the study said.
But infections started to fall in the over-55s, in a clear sign of the effect of booster vaccine doses — with more than 18.6million people now having had a third dose according to Government data.
No10 unveiled its new scheme to vaccinate all over-18s by the end of January on Tuesday, with the UK today buying 114million more doses in an effort to stop the spread of the new supermutant Omicron variant.
Professor Tim Spector, the epidemiologist behind the study, warned the variant has 'rudely awakened' the UK to the pandemic and encouraged more volunteers to continue tracking their symptoms to help monitor the strain.
Meanwhile, ministers today moved to poise the UK to start administering vaccines to primary school children amid fears of a looming wave caused by the variant.
They asked their independent vaccine advisers the Joint Commission for Vaccination and Immunisation (JCVI) and chief scientists Sir Patrick Vallance and Chris Whitty to consider the move.
But the UK's chief strategy for dealing with the strain remains vaccinating more vulnerable, older age groups, according to business minister George Freeman.
The ZOE symptom-tracking study estimated that 80,483 people fell ill on any given day in the week ending November 27, based on test results from around 650,000 volunteers
The figures show cases are highest in children aged under 18, who are seeing more than 32,000 symptomatic infections per day — although the numbers have fallen over the week.
Covid was most prevalent in the East Midlands, East of England and South East, where one in 57 people were infected per day during the week
Ministers are 'standing ready' to vaccinate five to 11-year-olds against Covid
The UK is poised to start administering Covid vaccines to primary school children amid fears of the looming Omicron wave.
Ministers have asked their independent vaccine advisers and chief scientists Sir Patrick Vallance and Chris Whitty to consider the move.
George Freeman, a business minister, told Sky News today: 'We're looking at the science on that and the balance of the rollout.
'(Sir) Patrick Vallance, our chief scientist, and (Professor) Chris Whitty are advising on that and it is their advice that guides us.'
He said the priority was vaccinating older adults who will be most vulnerable to Omicron if the mutant virus becomes widespread in the UK.
Mr Freeman added: 'The data at the moment suggests that young children are much less vulnerable but, as and when that data changes, we are guided by the science and we stand ready, which is partly why we have procured the vaccines - to make sure we can deliver what our citizens and patients need.'
Professor Spector said: 'Omicron has rudely awakened many countries, including the UK, from the slumber they had fallen into over Covid.
'While we need more data to understand the risks this variant presents, I would advise the public not to panic, but remember that it's important for everyone to be more cautious.
'Getting your third vaccine, wearing face coverings, avoiding big indoor crowds, and staying home if you feel unwell with cold-like symptoms are some of the best ways to slow the spread.
'The ZOE Covid Study is going to be one of the key tools in the fight against this new variant.
'We need everyone logging their symptoms, test results and vaccines in the app to quickly understand this new variant and help the world keep it at bay.'
The study estimated the R rate — the average number of people an infected person will pass the virus onto — is around 1.0 for the whole of the UK.
Figures show cases are highest in children aged under 18, who are seeing more than 32,000 symptomatic infections per day — although the numbers have fallen over the week.
In contrast, people aged 75 and over have the lowest level of illness, with less than 1,000 cases estimated in the age group each day.
Covid was most prevalent in the East Midlands, East of England and South East, where one in 57 people were infected per day during the week.
London and the North West had the lowest rates with one in 68 people falling ill with the virus during the week.
Figures from the UK Health Security Agency (UKHSA) yesterday showed Britain's Covid crisis appeared to pick up again, with cases and deaths increasing together for the first time in four days.
Britain recorded 48,374 new cases over the last 24 hours, up 10.8 per cent on last week's total of 43,676.
It was the first time the amount of positive tests increased week-on-week since last Friday, despite eight new cases of the supermutant Omicron variant being detected in England yesterday, bringing the UK's total to 22.
Likewise, the number of people dying with the virus increased 14.8 per cent to 171 today, up from 149 recorded last Wednesday.
But hospitalisations continued to fall, with 706 people admitted to hospital with coronavirus on Saturday, the latest date data is available for.
The Government data showed 393,000 adults received their third booster vaccine dose yesterday, taking the total number of people fully vaccinated against the virus to 18.6million.
Some 30,500 received their first dose, while 32,000 were given second jabs.
Pfizer boss Dr Albert Bourla today said Britons could need a Covid vaccine every year to maintain its 'very high' levels of protection.
Dr Bourla, who heads up the UK's top vaccine supplier, suggested in an interview that top-up jabs could be needed for years to come.
He said Pfizer was already working on a tweaked jab to fight the Omicron variant, which may be better at evading vaccine-induced immunity than other variants.
It comes after the UK purchased another 114million doses of Covid vaccines that could be edited to fight variants.
The deal suggests ministers are preparing to boost the nation's immunity for at least the next two winters.
Dr Bourla told the BBC: 'Based on everything I have seen so far, I would say that annual vaccinations... are likely to be needed to maintain a very robust and very high level of protection.'