UK’s coronavirus R rate ‘may be above 1’, experts fear – as South East, South West and Midlands see rise
THE coronavirus R rate could be above the crucial value of 1 across the UK, experts fear.
Three region have seen a slight increase in the vital measure since last week – while every range is now at or above 1.
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When the R value is below one, it means transmission is low and the epidemic is shrinking – but greater than 1 number suggests it’s growing.
The values are shown as a range, which means the true R rate most likely lies somewhere between the upper and lower estimates.
Experts warn that as Covid cases are much lower than they were at the peak of the pandemic, the R rate is more sensitive to even small outbreaks.
They also caution that there is a delay in the estimates as scientists use a range of data sources, which can take time to collate.
Conflicting figures
It comes as separate official figures today suggest that the country’s coronavirus outbreak is shrinking.
Data from the Office for National Statistics estimates that there are now just 2,200 new cases per day – that’s down for a third week in a row.
Similar statistics from the King’s College Covid Symptom Tracker also suggested the outbreak is shrinking – estimating 1,200 new daily cases.
The latest figures published today by the Scientific Advisory Group for Emergencies (SAGE), which advises the government, paints a slightly different picture.
On the brink
It suggests that the R rate for the UK as a whole is dangerously close to the crucial 1 value – and is sitting somewhere between 0.9-1.1.
This overall figure is unchanged from last week however the range for England has increased slightly from 0.9-1.0 to 0.9-1.1.
Meanwhile, the regional breakdown suggests there has been some small increases in the R rate in the Midlands and the South.
In the South East, the range is now at 0.9-1.1, up from 0.8-1.0 last week, while the South West was between 0.8-1.1 last week and is now at 0.9-1.1.
The Midlands, which is seeing some areas such as Birmingham in local lockdown, has seen a marginal increase from 0.8-1.0 last week to 0.8-1.1 today.
It means that the upper estimate for every region in England is now either at or above the crucial value of 1.
But experts warn that with infections so low, even the smallest cluster of cases could affect the range.
There is also a significant amount of variability across a region.
Prof Keith Neal previously said that local Covid clusters can also push the R rate up for an entire region when it may just be one small area.
The epidemiologist at the University of Nottingham said: “Making estimates of R with small number of cases becomes increasingly difficult and inaccurate. Hence the wide range of the estimates.”
Growth rate
As a result, the Government began publishing the country’s “growth rate” – which reflects how quickly the number of infections are changing day-by-day.
If the rate is greater than zero, then the epidemic is growing, but if it is less than zero then it will shrink.
The growth rate published today is from -2 per cent +1 per cent – meaning the epidemic is somewhere between growing and shrinking.
A Government spokesperson said: “A growth rate between -2 per cent and +1 per cent means the number of new infections is somewhere between shrinking by two per cent and growing by one per cent every day.
“The UK estimates of R and growth rate are averages over very different epidemiological situations and should be regarded as a guide to the general trend rather than a description of the epidemic state.”
They added: “We have been seeing indications that these values may be increasing, with estimated ranges increasing slightly from previous publications.
“Recent changes in transmission are not yet fully reflected in these estimates because the data used to calculate R and growth rate reflect the situation from a few weeks ago.
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“It is also important to recognise that these are estimates, and there is a high degree of uncertainty with them.”
Pointing to a time delay in gathering data on the R rate, they continued: “For this reason, Sage does not have confidence that R is currently below 1 in England.
“We would expect to see this change in transmission reflected in the R and growth rate published over the next few weeks as we gain more certainty of what is currently happening.”