Coronavirus reproduction number unchanged from last week

A man wearing a face mask walks past the Bank of England
A man wearing a face mask walks past the Bank of England - (Copyright PA Wire)
14:52pm, Fri 28 Aug 2020
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The reproduction number (R value) of coronavirus across the UK remains unchanged since last week, and is still above 1.0.

Data released on Friday by the Government Office for Science and the Scientific Advisory Group for Emergencies (Sage) shows the estimate for R across the UK is between 0.9 and 1.1.

The growth rate of coronavirus transmission, which reflects how quickly the number of infections is changing day by day, has changed slightly.

For the whole of the UK the latest growth rate is between minus 2% and plus 1% per day, a slight change from between minus 3% and plus 1% last week.

The growth rate means the number of new infections is somewhere between shrinking by 2% and growing by 1% every day.

The most likely value is towards the middle of the range, experts say.

Scientists say there have been indications that these values may be increasing, with estimated ranges rising slightly from previous publications.

The R number represents the number of people each Covid-19 positive person goes on to infect.

In England, the R is between 0.9 and 1.1, and the growth rate is minus 2% to plus 1%.

Recent changes in transmission are not yet fully reflected in the estimates because the data used to calculate R and growth rate reflect the situation from a few weeks ago.

Epidemiological data, such as hospital admissions, ICU admissions and deaths, usually take two to three weeks to reflect changes in the spread of disease.

This is because of the time delay between initial infection and the need for hospital care.

Therefore, the figures published on Friday more accurately represent the average situation over the past few weeks rather than the current situation.

But models that use Covid-19 testing data, which have less of a time delay, indicate higher values for R in England, the Government Office for Science statement said.

It added: “For this reason, Sage does not have confidence that R is currently below 1.0 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.”

HEALTH Coronavirus - (Copyright PA Graphics)

The scientists warn that estimates of R and growth rate per day are less reliable and less useful in determining the state of the epidemic when disease incidence is low, or where there is significant variability in the population, for example during local outbreaks.

They say when this is the case, estimates of R and growth rate become insufficiently robust to inform policy decisions.

In the East of England, the growth rate is unchanged at between minus 3% and zero, and the R number is 0.8-1.0.

In London, the growth rate is unchanged at between minus 2% and plus 1%, and the capital’s R rate is also unchanged at 0.9-1.1.

The Midlands has a growth rate of between minus 3% and plus 1%, a change from between minus 4% and zero, and an R number has increased slightly from 0.8-1.0, to 0.8-1.1.

In the North East and Yorkshire, the growth rate is between minus 3% and plus 1%, with an unchanged R number of 0.8-1.0.

The growth rate in the North West is between minus 3% and plus 1%, a slight change from between minus 2% and plus 1%. The R value here is unchanged at 0.9-1.1.

In the South East, the growth rate is between minus 2% and plus 1%, a change from between minus 4% and zero last week.

The R value in the region is up from 0.8-1.0, to 0.9-1.1.

The South West has a growth rate of between minus 2% and plus 2%, compared with between minus 1% abd plus 2% last week. Its R value is 0.9-1.1.

The latest figures from the Office for National Statistics (ONS) show that there were around 2,200 people per day in private households in England estimated to be newly infected with Covid-19 between August 14 and 20.

This is a decrease on the previous estimate of 2,400 between August 7 and 13.

The organisation said there is not yet enough evidence to say there has been a fall in new infections in the most recent week and therefore “we continue to report that the incidence rate for England remains unchanged”.

Separate ONS figures showed that north-west England once again had the highest coronavirus mortality rate, but rates for all regions of England for the month of July were down on the previous month.

Areas of Kent had some of the highest coronavirus mortality rates for local authority areas in England in July, but again rates dropped from levels seen in June.

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