Coronavirus: what is the R value and why does it matter?
Boris Johnson says Britain has reached coronavirus peak as R value falls
![UK lockdown coronavirus](https://cdn.mos.cms.futurecdn.net/Z7wmH6JozNDT4BRvgPdH9A-415-80.jpg)
Boris Johnson has pledged to explain next week how schools and workplaces will safely reopen once lockdown restrictions are eased, as he claimed the UK was past the peak of the coronavirus outbreak.
Despite announcing an increase of 674 in the death toll of the virus, the prime minister suggested the worst was over.
The Guardian notes that Johnson “laid particular emphasis on the R value”, a figure the government has been attempting to keep below 1.
Subscribe to The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
![https://cdn.mos.cms.futurecdn.net/flexiimages/jacafc5zvs1692883516.jpg](https://cdn.mos.cms.futurecdn.net/flexiimages/jacafc5zvs1692883516-320-80.jpg)
Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
But what is the R value - and why does this figure hold the key to ending the lockdown?
What is an R value?
The R value - also known as R0 or R naught - refers to the average number of people that one infected person will go on to infect. As such, it is a measure of how transmissible, or contagious, a disease is - but not how deadly.
Scientists use the R value to “predict how far and how fast a disease will spread, and the number can also inform policy decisions about how to contain an outbreak”, says the Daily Express.
As Business Insider notes, an R value of one means the “average person who gets that disease will transmit it to one other person” - or in other words, the disease is spreading at a stable rate.
But “an R0 of more than one means the disease spreads exponentially”, the news site adds.
Diseases with exceptionally high R values include measles, with an average estimated value of 18, and mumps, with a value of ten, Healthline reports.
Although government advisers have suggested that the UK’s R value for the new coronavirus is stable or even dropping, modelling has shown that in most cases where lockdown measures are lifted, the R value quickly rises above one.
This was seen in Germany, which last week considered the reintroduction of strict lockdown measures after Chancellor Angela Merkel warned that hospitals in Germany could be overwhelmed by the end of June if the R value rises even slightly.
–––––––––––––––––––––––––––––––For a round-up of the most important stories from around the world - and a concise, refreshing and balanced take on the week’s news agenda - try The Week magazine. Start your trial subscription today–––––––––––––––––––––––––––––––
What is the current situation in the UK?
The Guardian reports that the government’s scientific advisers currently believe the R value to be “between 0.6 and 0.9”. However, England’s chief medical officer, Chris Whitty, has urged caution.
“As soon as R goes over one, then you restart exponential growth – it may be slow if it is just over one, it may be a lot faster if it goes a lot above one – but exponential growth restarts and, sooner or later – and the higher it is, the sooner it is – the NHS will go back to the risk of being overwhelmed and the number of cases will go up,” Whitty told yesterday’s daily briefing.
As Sky News notes, decreasing the rate of infections to a “manageable level” is one of the government’s five tests that must be satisfied before the lockdown is lifted.
“The number of confirmed cases of coronavirus has been steadily decreasing,” the broadcaster says, “although it is accepted that the true number of cases is likely to be much higher than the reported amount”.
Create an account with the same email registered to your subscription to unlock access.
Sign up for Today's Best Articles in your inbox
A free daily email with the biggest news stories of the day – and the best features from TheWeek.com
-
Big Tech's answer for AI-driven job loss: universal basic income
In The Spotlight A new study reveals the strengths and limitations
By Joel Mathis, The Week US Published
-
'I will not be silent' on Gaza, says Kamala Harris
Speed Read In a meeting with Israeli Prime Minister Benjamin Netanyahu, Harris supported Israel's right to defend itself while expressing a desire to end Palestinian suffering
By Arion McNicoll, The Week UK Published
-
'How long can TikTok dominate as a social network?'
Instant Opinion Opinion, comment and editorials of the day
By Justin Klawans, The Week US Published
-
Brexit, Matt Hancock and black swans: five takeaways from Covid inquiry report
The Explainer UK was 'unprepared' for pandemic and government 'failed' citizens with flawed response, says damning report
By Harriet Marsden, The Week UK Published
-
India's toxic alcohol problem
Under the Radar Bootleggers add lethal methanol to illegal liquor to cheaply increase potency, leading to widespread casualties
By Harriet Marsden, The Week UK Published
-
Should masks be here to stay?
Talking Points New York Governor Kathy Hochul proposed a mask ban. Here's why she wants one — and why it may not make sense.
By Anya Jaremko-Greenwold, The Week US Published
-
Covid might be to blame for an uptick in rare cancers
The explainer The virus may be making us more susceptible to certain cancers
By Devika Rao, The Week US Published
-
Long Covid and chronic pain: is it all in the mind?
The Explainer 'Retraining the brain' could offer a solution for some long Covid sufferers
By The Week UK Published
-
In what countries is assisted dying legal or under review?
In the spotlight More countries are granting more people the right to die
By Devika Rao, The Week US Published
-
Nigeria's worsening rate of maternal mortality
Under the radar Economic crisis is making hospitals unaffordable, with women increasingly not receiving the care they need
By Harriet Marsden, The Week UK Published
-
Dengue hits the Americas hard and early
Speed Read Puerto Rico has declared an epidemic as dengue cases surge
By Peter Weber, The Week US Published