THE country’s top experts are due before MPs to explain the evidence for a second national lockdown.
Chief scientific adviser Sir Patrick Vallance and chief medical officer for England Professor Chris Whitty will appear before the Science and Technology Committee today.
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It comes after experts raised concerns over the data presented at the Prime Minister’s press conference on Saturday evening.
A graph shown by Sir Patrick 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OUT OF DATE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.”
OLDER MODEL
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.
The PA news agency understands 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.”
SECOND LOCKDOWN
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.”
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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.”
