The latest React study from Imperial College London and Ipsos Mori, which saw more than 142,900 volunteers tested in England between January 6 and 15, showed one in 63 people were infected.
This is an increase of 50% since early December, with national prevalence of Covid-19 from 0.91% in early December to 1.58% last week.
This puts the national R rate at 1.04 – which means the number of people being infected is increasing. The pandemic grows when R is above 1 and shrinks when it falls below 1.
Professor Paul Elliott, director of the programme at Imperial, warned if prevalence continues to be so high ‘more and more lives will be lost’.
‘Our data are showing worrying suggestions of a recent uptick in infections which we will continue to monitor closely,’ he said.
‘To prevent our already stretched health system from becoming overwhelmed, infections must be brought down; if prevalence continues at the high rate we are seeing then hospitals will continue to be put under immense pressure, and more and more lives will be lost.
‘We all have a part to play in preventing this situation from worsening and must do our best to stay at home wherever possible.’
These results may appear to contradict the falling trend in new daily reported cases at the start of this week, but it is thought the study may be ahead of official figures because it tests people routinely, whether they have symptoms or not.
But researchers added the results may not yet show the impact of the third national lockdown.
The report also includes mobility data for the first time, based off information on Facebook.
Peoples’ movement appeared to decrease at the end of December and increase at the start of January, which the scientists said helps to explain the change in prevalence.
There was a rise in infections across all adult age groups but it was highest in 18 to 24 year olds – and had more than doubled in the over 65s age group.
Regionally London saw the highest increase from 1.21% to 2.8%, while there were also rises in the south east, east of England, West Midlands, south west and north west.
The only region to see a decrease was Yorkshire and the Humber, and although case numbers remained stable in the East Midlands and north east, researchers warned numbers are still high even in these areas.
Health secretary Matt Hancock said the findings show ‘why we must not let down our guard over the weeks to come’.
‘Infections across England are at very high levels and this will keep having a knock-on effect on the already significant pressures faced by our NHS and hospitals,’ he added.
‘It is absolutely paramount that everyone plays their part to bring down infections.’
It comes as the UK recorded its deadliest day from coronavirus yesterday with 1,820 deaths reported.
Prime minister Boris Johnson described the figures as ‘appalling’ and warned ‘there will be more to come’, saying the country is seeing the result of the new variant that spread rapidly just before Christmas.