England’s R number has risen to between 0.9 and 1.2, official data shows.
Last week, the R value – or reproduction number – was between 0.8 and 1.0.
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The reproduction value indicates the average number of people each COVID-positive person goes on to infect.
An R number between 0.9 and 1.2 means that every 10 people infected will pass on the virus to between 9 and 12 other people on average.
Anything above 1 means the coronavirus outbreak is growing exponentially – but below 1 means the case rate is shrinking.
Earlier, estimates from the Office for National Statistics (ONS) showed that around one in 80 people in private households in England had COVID in the week to 14 August.
The figure was down slightly from one in 75 in the previous week.
One in 80 is the equivalent of about 698,100 people.
As cases remain high, England’s chief medical officer Professor Chris Whitty has urged people not to delay getting a vaccine.
He tweeted: “The great majority of adults have been vaccinated.
“Four weeks working on a COVID ward makes stark the reality that the majority of our hospitalised COVID patients are unvaccinated and regret delaying.
“Some are very sick including young adults. Please don’t delay your vaccine.”