The UK’s coronavirus reproduction number, or R rate, is estimated to be between 0.7 and 1.1, according to government figures.
Last week, it was between 0.8 and 1.0. Which was the first time since December 11 the R rate had been below 1, when the more transmissible variant of the disease first found in Kent began to take hold.
R measures the number of people, on average, that each sick person will infect.
If R is greater than 1 the epidemic is generally seen to be growing; if R is less than 1 the epidemic is shrinking.
Here’s what the R is in each region
In England as a whole, the R rate is 0.7 to 1.0, while regionally it is as follows:
- East of England 0.7 to 0.9 (last week: 0.6 to 0.9)
- London 0.6 to 0.9 (0.7 to 0.9)
- Midlands 0.8 to 1.1 (0.9 to 1.2)
- North-east and Yorkshire 0.8 to 1.1 (0.8 to 1.1)
- North-west 0.8 to 1.1 (0.9 to 1.2)
- South-east 0.7 to 0.9 (0.7 to 1.0)
- South-west 0.8 to 1.1 (0.9 to 1.2)
The R rate in Scotland has fallen to between 0.7 and 1.0 from 0.8 to 1.1. Nicola Sturgeon said on Thursday the country is making “progress in suppressing the virus”.
In Northern Ireland, the reproduction rate for new cases is between 0.65 and 0.8.
And in Wales, the R rate is estimated to be around 0.7, meaning the virus is on the decline.
The R number, explained
The R number – sometimes referred to as the R0 – is the “basic reproduction number”. It’s used to measure the transmission potential of a disease.
The R value represents the number of people that one infected person will, on average, pass the virus on to. It’s influenced by characteristics of the specific disease (in this case, Covid-19), such as how easily it passes from person to person. Human behaviour – i.e. how closely we follow social distancing measures – will also impact the R number.
When the R number is below 1, this suggests the number of cases is shrinking. Anything above 1 suggests cases and subsequent infections are growing – and is a cause for concern, because cases snowball.
An R rate of 0.8 to 1.0 means every 10 people infected will on average infect eight to 10 others between them.
While it can help indicate if lockdown measures are working, the R number doesn’t offer the full picture; the R value can show if an epidemic is getting bigger or smaller, but not how large it is.
“R should always be considered alongside the number of people currently infected,” the government website explains. “If R equals 1 with 100,000 people currently infected, it is a very different situation to R equals 1 with 1,000 people currently infected.”