Coronavirus infections may be falling according to the biggest national swab testing surveillance study.
Data from 74,000 random swab tests across England suggest the R reproduction value has dipped below 1.
Imperial College London’s REACT study calculated between October 26 and November 2 it was at 0.85 just before lockdown.
Scientists behind the data are trying to establish what happened to trigger a fall in infections before a small increase.
Overall over the period the data suggested an R below 1.
Author Prof Steven Riley said: “This is consistent with a very slight decline.”
The fall in infections came just before half term reaching a low point on October 30 before increasing a little in the final few days of the study up to November 2.
The team speculated that the dip may have been due to rainy weather before a slight increase due to people socialising before lockdown.
Author Prof Steven Riley said: “There was a lot happening in that week. There was half term in many areas. October was a wet month and there was a lot of talk about lockdown.”
Asked whether the uptick could be due to people paying one last visit to the pub, Prof Riley replied: “It could be.”
Scientists warn the total number of people infected is still very high and say national lockdown was necessary to stop rising deaths.
In the most recent survey period, scientists estimated 1.3% of the entire population of England – around 1 million people – had the virus at any one time.
But the REACT study did show promising results in the week to November 2 – known as ’round 6b’ of the study.
The R number in round 6b was said to be 0.77 in London, 0.83 in the North West and 0.88 in Yorkshire and the Humber. It was only above 1 in the North East (1.15) and East of England (1.12).
In round 6a the R number was 2.86 in London, 1.21 in the North West, 1.54 in Yorkshire and the Humber, 0.57 in the North East and 2.18 in the East of England.
The REACT study’s estimate of R is not the official R number. That is compiled by government advisors SAGE by piecing together several different studies at the same time.
However, it is the second study released today to suggest the R number had dipped below 1.
Data from the ZOE Covid-19 Symptom app suggested the ‘R’ rate in every nation in the UK appears to now be below 1.
R means how many people are infected by each person with Covid-19, on average. More than 1 and the rate of virus grows each week; less than 1 and the rate of virus shrinks.
Boris Johnson has said the R number must be below 1 before the current month-long lockdown in England can be lifted.
The REACT study has seen 930,000 people take part by completing home swab testing kits and gives a picture of infection levels just before lockdown.
Any drop in the national outbreak appears to be driven by falling infections in primary school age children and 19 to 24 year olds.
REACT study director Prof Paul Elliott said the data may suggest a “plateauing” of infections nationally.
He said: “Because of the shape of that very late data going down and then up, it’s very difficult to summarise that.
“Overall though the [infections] data shows it has slowed since the rapid rise in the previous round.
“Our latest round offers robust data on England’s coronavirus situation up until just three days before the country entered its second nation-wide lockdown.
“We’ve shown that the prevalence of infection has remained high, reinforcing the need for people to act to help bring infections down and control the virus.
“These important data will be a critical baseline from which to determine if the new measures are effective at curbing the growth of the epidemic.”
The data will be fed into Sage which calculates the official R value for England. Sage will publish an updated R range on Friday.