Scientists tracking the spread of coronavirus in England say infection levels in the community may have risen at the start of the latest lockdown.
Infections in 6-15 January were up by 50% on early December, with one in 63 people infected, Imperial College London’s initial findings suggest.
Swab tests from 143,000 people indicate 1.58% had the virus during in early January – up from 0.91% in December.
Ministers say the report does not yet reflect the impact of the lockdown.
The latest round of results from Imperial College’s React-1 infection survey – one of the country’s largest studies into Covid-19 infections – are interim with the full set of results to be published in a week’s time.
But Imperial College London’s Prof Paul Elliott warned if the high prevalence continues “more lives will be lost”.
The report also says there are “worrying suggestions of a recent uptick in infections” and Prof Elliott said the third lockdown – introduced on 6 January – was not having the same impact as the first, in April.
London had the highest level in the January period – 2.8%, up from 1.21% in early December.
Prof Elliott old BBC Radio 4’s Today programme the current R rate – which represents how many people an infected person will pass the virus on to – was “around 1”.
“We’re seeing this levelling off, it’s not going up, but we’re not seeing the decline that we really need to see given the pressure on the NHS from the current very high levels of the virus in the population,” he said.
“To prevent our already stretched health system from becoming overwhelmed, infections must be brought down,” Prof Elliot added.
Before the Covid rules were tightened, the restrictions faced by people in England varied depending on where they lived.
The researchers say the government’s latest daily case figures, which show a slowdown, may reflect a drop in cases just after Christmas, which is only now being registered.
And they suggest infection levels may have gone up in early January as a result of people’s activity increasing after the Christmas holiday period.
They admit there is some uncertainty in their data amid a “fast-changing situation” but say it is more up to date than the daily government figures because it does not rely on those being tested developing symptoms and then waiting to have their infections confirmed by a laboratory.
The UK recorded another all-time high of daily coronavirus deaths on Wednesday. A further 1,820 people died within 28 days of a positive Covid test, according to government figures – taking the total number of deaths by that measure to 93,290.
