Coronavirus could be growing exponentially in the northwest of England, according to data revealing the regional reproduction rate for the first time.
R is thought to be 1.01 in the northwest and 1 in the southwest, in results shown by a tool created by Public Health England (PHE) and Cambridge University.
In only one region — the northeast and Yorkshire — was it below 0.9, the data suggested.
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Health secretary Matt Hancock said the government’s Sage committee had suggested R was below 1 in all regions — but he admitted there was a “challenge” in the northwest and southwest areas.
The tracker gives a median value for R in each part of the country; the precise figure lies between upper and lower estimates. In London, for example, R is between 0.72 and 1.2, with a median value of 0.95.
The R rate entails the average number of people infected by one person with coronavirus.
“If the R is higher than 1 that means this disease is growing exponentially and will keep on spreading to more and more people,” Sir Patrick Vallance, the UK’s chief scientist, has previously said. The closer to 1, the slower the growth.
Speaking at the daily Downing Street press conference, the health secretary, Matt Hancock, said keeping the R number below was vital. Deaths now exceed 40,000.
He said: “The discussion of the higher R in the northwest and the southwest that’s estimated compared to the rest of the country is an important part of moving towards a more localised approach rather than a national approach to the lockdown.
“It’s very important that you look at all of these studies in the round. The overall assessment that is brought together by Sage that advises the chief medical officer is the one that I look at.”
He added: “The overall view of Sage is that the R is between 0.7 and 0.9 and it is higher in the southwest of England and the northwest but it remains below 1 in each area.”
Mr Hancock also said the government was “increasingly” interested in tackling flare-ups of the virus with local lockdowns, rather than nationwide measures.
“We’ve been doing this over the last few weeks, for instance there was a flare-up in Weston-super-Mare which we successfully got under control,” he said.
On the BBC’s Newsnight, Greg Fell, the director of Public Health Sheffield, said he expected to receive data on infections for a level of about 1,500 people this weekend but warned councils needed more specific data to help track the local infection rate.
“I think I’m going to need that data regularly and in real time so I can spot trends over a long period of time. Preferably, I would like that data at person level,” Mr Fell said.
“I don’t particularly need the data but I need to know that someone somewhere is keeping a really really close eye on that data, right down to person level because that’s the only way to spot trends.”
Earlier on Friday, the Office for National Statistics said there were about 5,600 new infections a day in England, down from 8,000 last week.
Figures on how many people have coronavirus at any one time, based on swab results from households across the country, showed an estimated 39,000 new infections per week in England between 26 April and 30 May.
Professor Sheila Bird, from the University of Cambridge, who was not involved in the work, said: “Today’s report is the regional update that everyone has been eager to have. But the findings are the opposite of reassuring.
“In no region of England is the effective reproduction number assuredly below 1 with regions’ median estimates ranging from 0.89 to 1.01. No wonder members of Sage are worried.”
The figures come as Boris Johnson’s government implements a new phase of lockdown easing in England, with non-essential shops due to reopen on 15 June, children going back to school and people allowed to gather in larger groups than before.
Mr Johnson has come under fire for the way those measures have been brought in, apparently with little regard to a risk scale that the government itself created.
Relaxation of lockdown in other parts of the UK is proceeding at a slower pace.
Last week, Rishi Sunak denied that ministers were acting “in a reckless or big bang way”. Instead, he said, revisions to lockdown were “measured and phased”.
Dr Yvonne Doyle, PHE’s medical director, said in a statement: “Our estimates show that the regional R numbers have increased although they remain below 1 for most of England – this is to be expected as we gradually move out of lockdown.
“It is vital that everyone continues with social distancing, practising good hand hygiene and must remain at home and order a test if they have symptoms.”
In a blog post about its new tool, PHE added: “The R number is only one component that determines the rate of growth of the epidemic, and does not say anything about the rate of occurrence of new infections, the prevalence of infection across communities and the current burden faced by the healthcare system.
“It should, therefore, not be used as the sole indicator of the current threat posed by an epidemic.”