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 admit 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, was called into question.
Scientists later revealed it was based on data from before the tiered restrictions were introduced and when the R rate was higher.
Labour MP Graham Stringer suggested that the slide presented had "frightened a lot of people around the country".
But 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."
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."
Meanwhile, Prof Whitty 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 continued: "There are some hospitals, particularly in the North of England which have reached Covid occupancy higher than in the first wave.
"Our worry there is although in those areas it looks as if the increase in rates is flattening, it’s [the R rate] not fallen below one, it’s still going up.
"If it carries on going up from this very high base they will get into serious trouble on inpatients very quickly.
"There are other bits of the country, for example in the South West, where the rates of increase are higher than the North now but the bed capacity is lower.
"So, although they look further away at the moment they could hit difficulties quickly."
He added that there are several different "barriers" in which the NHS must go through before it hits capacity.
“The first thing we would have to do – and already having to do in some parts of the country – is cancelling non urgent elective care," he said.
"Then you go onto start to impinge on urgent but non-emergency care, then you get into the acute care being constrained and finally you get into intensive care capacity being used up.
“We’re already seeing parts of the country having to cancel non-urgent emergency care.
“If this continues, people worry rightly about all the non-Covid care being affected.
“The way you prevent those services being impinged on and potentially being slowed right down, or even in some cases cancelled, is to keep the Covid rates down.
“If you don’t that is going to erode the NHS’s capacity to do not just the Covid care, but the non-Covid care as well.”
Sir Patrick was also pressed on data presented at the Prime Minister's press conference on Saturday evening.
One of the graphs he showed 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.
OUT OF DATE
Researchers at Oxford University also highlighted that if it had been correct, then deaths would be at around 1,000-a-day now.
The current rolling seven day average death toll is around 265, while yesterday's grim figure was 136.
It's since emerged that the modelling was based on an estimated R rate of 1.3 to 1.5, which was published on October 16.
The crucial value dropped the following week on October 23 and was estimated to be between 1.2 and 1.4.
It then fell slightly again and in new figures published on Friday – the day before the press conference – it was estimated to be between 1.1 and 1.3.
The Government Office for Science (GOS) has so far refused to release the key to the graph, which would explain how it was modelled.
Instead, it says "relevant papers would be published shortly".
Science Committee chairman Greg Clark said: "This is an important moment in the handling of the pandemic.
"Parliament must have the chance to understand and question the evidence and rationale behind the new restrictions in advance of Wednesday's debate and vote.
"I am grateful to Sir Patrick Vallance and Professor Chris Whitty for having agreed immediately to my request to appear before the science and technology committee on Tuesday."
Professor Carl Heneghan, director of the Centre for Evidence Based Medicine at Oxford University, said that the graphs used at Saturday's Downing Street press conference with estimates of Covid deaths were based on models from three weeks ago.
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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