Three-tier lockdown WAS working admit Vallance and Whitty – as they defend 'scary' 4,000 daily deaths dossier
THE country's top experts have defended their "worst case scenario" predictions – but admitted the three-tier lockdown system was working.
Sir Patrick Vallance and Professor Chris Whitty were hauled before MPs today to explain their evidence for a second national lockdown.
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It comes after their doomsday 4,000 daily deaths scenario, which was presented during Saturday night's press briefing, came under fire.
Scientists later revealed the modelling was complied on October 9 – five day
Sir Patrick presented a graph which suggested that without another national lockdown there could be 4,000 daily deaths by December 20.
This worst case scenario forecast suggests there would be more than four times as many fatalities as on the worst day of the first peak.
But scientists have pointed out that this modelling was complied on October 9 – five days before new tier restrictions came into place.
Labour MP Graham Stringer suggested that the slide presented had "frightened a lot of people around the country".
Defending the data, Sir Patrick told the Committee: "I think I positioned that, and if that didn't come across then I regret that, but I positioned that as a scenario from a couple of weeks ago, based on an assumption to try and get a new reasonable worst-case scenario.
"And that those figures therefore were not as reliable as the six-week figure which I spent time talking about.
"So, those figures were ones done by major academic groups based on those assumptions and, in the spirit of trying to make sure that things are shared and open, they are the things that we have seen, and it's important and I think people see that."
In the spirit of trying to make sure that things are shared and open, they are the things that we have seen
Sir Patrick compared the situation to one back in September when he presented figures predicting 50,000 cases a day and 200 deaths.
He explained that at that time, they had not been there to "scare people" but to "give a scenario".
"As it happens, the numbers turned out to be very close to that, by the time we got there," he said.
"So it's very difficult to project forward in a way that doesn't inevitably lead to the problem of 'Is that real?'
"No, it's not real, it's a model, but it is what we need to understand because this is a disease which is spreading like all epidemics, in a way that will affect us in weeks to come but isn't felt today."
However, Prof Whitty said he had "never used" projections that looked further than six weeks ahead when advising ministers.
'TIERS WERE WORKING'
Both experts also admitted that the three-tier lockdown system, which was introduced on October 14, was beginning to have an impact.
However, they claim the restrictions were not working quick enough to prevent a surge in infections from overwhelming the NHS.
Prof Whitty said: "It’s difficult to be absolutely confident about how far their effect [tier system] has gone.
"I am confident that the Tier 2 has had an effect and that the Tier 3 has had a bigger effect.
"The community in the North and Midlands, where most of these are, and London, as well as parts of eastern England too, have responded remarkably to this.
"Because of that I’m confident that the rates are substantially lower than they would have been had those activities not happened.
"But the early indications we have at the present are that this has not achieved getting the R below one – it has brought it much closer to one – but it is still doubling over a longer period of time."
Prof Whitty also warned that the number of people in hospital with coronavirus has now hit 10,000, adding that evidence showed that there was an "exponential curve" in the number of hospital beds being occupied.
He told MPs that on September 7 there were 536 inpatient cases – at the beginning of October it was around 2,500 and "as of today it's actually breached 10,000 people in hospital".
"You don't need too much modelling to tell you that you are on an exponential upward curve of beds," he said.
Prof Whitty also suggested the death rate among people with coronavirus could possibly be halved by improved treatment – but warned the number of people dying was still increasing.
He told the committee the use of dexamethasone and the reduction in need to use ventilators had helped.
You don't need too much modelling to tell you that you are on an exponential upward curve of bed
"But these are going to reduce the mortality, they are not going to take it all the way down," he told MPs.
"The idea that there has been a huge transformation in the infection mortality rate would not be supported by the current data.
"There has been a reduction, I'm confident of that, there might have been a halving – it's difficult to tell currently on the current data, let us hope that is the case.
"But what we are seeing at the moment is numbers of deaths are going up really relatively steadily over the last two or three weeks."
The Government's chief scientific adviser Sir Patrick Vallance said: "I don't think the infection fatality rate has necessarily halved, I think the hospital mortality rate has gone down."
Prof Whitty said: "My 'halving' was that's the best we can hope for, I think it's probably less than that, actually."
The data behind the graph shown at Saturday's press conference was uncovered by Professor Carl Heneghan, director of the Centre for Evidence Based Medicine at Oxford University.
In a blog post written with Dr Daniel Howdon, senior research fellow in health economics at the University of Leeds, Prof Heneghan said one of the models had since revised down its estimated number of deaths.
The pair said on Monday that the University of Cambridge and Public Health England (PHE) model had estimated 1,000 deaths by November 1 but Government data showed an average of "just over 200".
The university's MRC biostatistics unit has since revised its projected deaths down from 588 on October 30 to 497 on November 15, the pair added.
It's reported that further models were submitted to Government scientific advisory groups as recently as last week.
Prof Heneghan and Dr Howdon said: "The slides leaked to the BBC on estimated Covid-19 deaths and presented at the Government press conference on the October 31 were based on different models from at least three weeks ago.
"Two SAGE [Scientific Advisory Group for Emergencies] model estimates have already proven to be invalid.
"We consider these analyses need checking with the raw data to verify the estimates against the actual death data and further verify whether the lower estimates reflect the actual data."
Their comments came after Prime Minister Boris Johnson announced a new national lockdown in England on Saturday.
Professor James Naismith, director of the Rosalind Franklin Institute, said that because of the time lag between infections and deaths, waiting for a model to prove accurate risked further deaths if no action was taken.
He said: "What even the most optimistic models agree on is that we will see around 500 deaths per day in two to three weeks (best case). We know these deaths will happen because of the number of people infected last week.
"What matters now is how many people are going to be infected each day this week and next week. This will determine how many people die in four weeks time."
He said predicting the future "always has uncertainty" but that we cannot afford to simply wait and see if existing measures start working.
Prof Naismith added: "If the virus continues at the rate we saw last week, then taking the two or three weeks to prove beyond any doubt that the current measures have failed, then we will be unable to avoid over 1,000 deaths a day (in a best case scenario) before Christmas.
"This is to put a hope over evidence and to risk at least 500 unnecessary deaths per day."
'WORST CASE SCENARIO'
Professor Neil Ferguson, of Imperial College London, said that the 4,000 deaths a day scenarios were "preliminary work" to create a new "reasonable worst case planning scenario".
He added: "SPI-M [Scientific Pandemic Influenza Group on Modelling] undertakes a wide range of modelling for government.
"The 'up to 4,000 deaths a day' scenarios represent preliminary work to generate a new reasonable worst case planning scenario to assist NHS and other Government planning."
He added: "Even allowing for the effects of the current tier system, the most recent SPI-M projections suggest that without further action, the second wave is set to exceed the first wave in hospital demand and deaths."
Dr Howdon said that the variation in the different models emphasised the high degree of uncertainty but said many of them had been "a long way off" in their predictions.
He added: "What we have done is look at the data and try to compare it to reality.
"Ultimately, if you compare them [the models] to the observed reality, they have generally been a long way off."
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