Coronavirus news: Boris Johnson urges public to abide by new Covid rules through ‘unquestionably difficult’ winter

Unclear how long new restrictions will last

 Cabinet Office minister Michael Gove was unable to say how long the new coronavirus measures are expected to last.

"What we hope is we can take appropriate steps now, which mean that if we succeed in beating back the virus, then we will in the future be able to progressively relax them," he told BBC Breakfast.

"But what I can't do is predict with absolute certainty."

Pressed on whether it would be months or weeks, Mr Gove said: "It is the case, as Professor Vallance and Chris Whitty pointed out yesterday, that we're going to have a challenging next six months."

Strict UK lockdown 'was necessary’

Professor Neil Ferguson, the epidemiologist whose advice to the prime minister led to the UK lockdown, has said he believes the strict lockdown introduced in March was necessary.  

He told BBC Radio 4’s The Life Scientific programme: “I think we got very close, particularly in London but also in other areas of the country, to hospitals being overwhelmed and so I think by the time we reacted, yes I think a strict lockdown was necessary.” 

Scientists estimated how lethal Covid-19 would be in February

Prof Ferguson, whose modelling helped shape the UK’s lockdown strategy, said scientists first estimated how lethal Covid-19 could be in the country back in February.  

The former government adviser said experts used data China shared online at the start of the pandemic combined with private data from collaborators to work out how lethal the virus could be in the UK.  

He told BBC Radio 4: “We concluded within a couple of weeks that it must be spreading predominantly from person to person and probably most importantly, and this was a little bit later, in February, we came up with the first estimates of how lethal this virus was and that of course is critically important if you’re going to make a judgement of are you going to shut down society to stop this virus.  

“We estimated in China itself about 0.6 per cent of infected people were dying but China has a younger population than the UK and this is a disease which predominantly we know kills the elderly so if you translate those values into the UK population we estimated about 0.9 per cent which is much, much more lethal than, say, seasonal flu.” 

Experts realised it would be ‘almost impossible to contain virus’

While it became apparent Covid-19 was quickly spreading across the globe in late February, epidemiologists realised they had a pandemic on their hands “a little earlier than that”, according to Professor Neil Ferguson.

The expert said he and other mathematical epidemiologists who do modelling realised “the sheer level of seeding of infection into multiple countries” meant it was “almost impossible that we would contain it”.

He told BBC Radio 4: “The broader measures countries were adopting we estimated would catch at most a third of cases, we now know probably more like 10 per cent, and we anticipated there was almost certainly spread going on in countries which wasn’t yet recognised and that was proved to be right.”

UK ‘could have seen 510,000 deaths if virus left to run amuck’

In his ninth report on the Covid-19 pandemic issued in mid-March, Prof Ferguson predicted the UK could expect about 510,000 deaths if it did nothing to mitigate the spread of the disease.  

Asked if this was his worst case scenario, he said: "We never anticipated we would do nothing but...if we just let the disease run amuck through the population we would have seen that level of mortality plus or minus 10, 20 or maybe even 50,000.  

“If we had done that, hospitals would have been completely overwhelmed and mortality probably would have been higher because we wouldn’t have been able to treat people but that is a kind of baseline against which you measure other policies which hopefully bring down that number." 

Prof Ferguson said he did not believe the figure was an overestimate given what we know now about the virus.

“I would completely stand by it,” he said. “If anything, it might have been an underestimate because we didn’t take account of the fact of what would actually happen to mortality rates if the health system collapsed. Mortality could have been even higher."

‘We are getting a revised picture of immunity’

Professor Ferguson said scientists are now trying to firm up the estimates that went into the modelling used at the start of the pandemic.

None of those have changed dramatically,  he said, but there have been some changes as researchers learn more about the virus such as asymptomatic transmission and immunity.

“Now we think that probably people who are completely asymptomatic, which is maybe a third of infections, whilst they do transmit sometimes they’re not anywhere near as infectious as people with symptoms and that’s a change of assumption. Back in March we had to make an assumption about that, now we actually have some data,” he told BBC Radio 4.

“We are getting a revised picture of immunity. Back in March we assumed immunity would be permanent. We now know rather more about immunity with this virus and we think it’s still right to say from the clinical data that there’s probably a higher degree of immunity for a few months but it does decay away so it’s likely people will get reinfected eventually and we are starting to see that.”

The prime minister is set to address the nation this evening to announce tighter coronavirus restrictions as the number of new infections continues to rise across the country.

My colleague Kate Ng has put together this guide on where the watch the announcement and what to expect:

UK herd immunity ‘not having appreciable effect as yet’

Professor Ferguson said herd immunity now appears to be having an effect in some countries - but not in the UK, although there could be a “hint” of it in some London boroughs.

He told BBC Radio 4: "It is in some communities in the world having an effect now. It’s probably having an effect in some areas of Brazil, probably in some areas of India. In this country in the UK it’s not having an appreciable effect as yet. 

“The most heavily affected area of the UK is probably London and there are probably a few London boroughs where there is a hint of herd immunity having an effect but it’s really too early to tell.”

‘Small increase’ in deaths with Covid-19 registered

There has been a small increase in deaths with Covid-19 registered in the latest weekly data for England and Wales, the Office for National Statistics has said.

The ONS cautioned the rise of 21 deaths in the week to 11 September may have been caused by the August bank holiday which could have delayed some death registrations.

Across the UK, including Scotland, there were 110 deaths mentioning Covid-19, 27 deaths less than the previous week. In England and Wales along there were 99 deaths, an increase of 21 since the previous week.

The number of deaths in hospitals was below the five-year average with 371 fewer deaths than expected in the latest week. The numbers of deaths in private homes and care homes were above the five-year average with 830 and 57 more deaths respectively.

The number of deaths involving Covid-19 increased across five of the nine English regions. The North West was the only English region to have lower overall deaths than the five-year average.

‘Trial and error to see what measures will curb second wave’

Professor Ferguson said the models for predicting what will happen in the future are good for projecting two or three weeks in advance but it will be “trial and error” to see what measures help curb the second wave of the virus in the UK over the coming months.

He told BBC Radio 4:  "Broad brush, I would say the models even we had back in March predicted what is happening exactly now. 

“We always said that once you lift lockdown measures, social distancing, beyond a certain degree, when you reopen schools, you are going to see a resurgence of transmission.”

But, he added: "We still don’t have a good enough handle on the details of where transmission happens and on human behaviour in response to interventions to model very nuanced detail intervention measures so we can’t tell the government what will be the effect of the ‘rule of six’ in a detailed way from a mathematical model.  

“So whilst we have very good models now for projecting the trajectory of the epidemic two or three weeks in advance, it will be trial and error to some degree to see what package of interventions are needed to keep on top of this second wave, to prevent more deaths and a full second wave occurring whilst minimising the economic cost of those interventions."