Burning question: how accurate was science that led to lockdown?
Previous work by professor whose paper convinced Government to act has been criticised by peers
‘We didn’t think it would be a cautionary tale for a new plague in the human population – but of course the cautionary tale is fully valid. This is déjà vu’
THE scientist whose calculations about the potentially devastating impact of the coronavirus directly led to the countrywide lockdown has been criticised in the past for flawed research.
Prof Neil Ferguson, of the MRC Centre for Global Infectious Disease Analysis at Imperial College in London, produced a paper predicting that Britain was on course to lose 250,000 people during the coronavirus epidemic unless stringent measures were taken. His research is said to have convinced Boris Johnson, the Prime Minister, and his advisers to introduce the lockdown.
However, it has now emerged that Prof Ferguson has been criticised in the past for making predictions based on allegedly faulty assumptions which nevertheless shaped government strategies and impacted the UK economy.
He was behind disputed research that sparked the mass culling of farm animals during the 2001 epidemic of foot and mouth disease (FMD), a crisis which cost the UK billions of pounds. And separately he also predicted that up to 150,000 people could die from bovine spongiform encephalopathy (BSE, or “mad cow disease”) and its equivalent in sheep if it made the leap to humans. To date there have been fewer than 200 deaths from the human form of BSE and none resulting from sheep to human transmission.
Mr Ferguson’s FMD research has been the focus of two highly critical academic papers which identified allegedly problematic assumptions in his mathematical modelling.
The scientist has robustly defended his work, saying that he had worked with limited data and limited time so the models weren’t 100 per cent right – but that the conclusions reached were valid.
Michael Thrusfield, professor of veterinary epidemiology at Edinburgh University, who co-authored both of the critical reports, said that they had been intended as a “cautionary tale” about how mathematical models are sometimes used to predict the spread of disease. He described his sense of “déjà vu” when he read Mr Ferguson’s Imperial College paper on coronavirus, which was published earlier this month.
That paper – Impact of nonpharmaceutical interventions (NPIS) to reduce COVID-19 mortality and healthcare demand – warned that if no action was taken to control the coronavirus, around 510,000 people in Britain would lose their lives.
It also predicted that approximately 250,000 people could die if the Government’s conservative approach at the time was not changed. The research, based on mathematical models, was key in convincing the Prime Minister that “suppression” – and subsequently lockdown – was the only viable option to avoid huge loss of life and an NHS meltdown.
This week, a second paper authored by Mr Ferguson and the Imperial team further predicted that 40 million people worldwide could die if the coronavirus outbreak was left unchecked. But scientists warned last night about the dangers in making sweeping political judgments based on mathematical modelling which may be flawed. In 2001, as foot and mouth disease broke out in parts of Britain, Prof Ferguson and his team at Imperial College produced predictive modelling which was later criticised as “not fit for purpose”.
At the time, however, it proved highly influential and helped to persuade Tony Blair’s government to carry out a widespread pre-emptive culling which ultimately led to the deaths of more than six million cattle, sheep and pigs. The cost to the economy was later estimated at £10 billion.
The model produced in 2001 by Prof Ferguson and his colleagues at Imperial suggested that the culling of animals should include not only those found to be infected with the virus, but also those on adjacent farms even if there was no physical evidence of infection.
“Extensive culling is sadly the only option for controlling the current British epidemic, and it is essential that the control measures now in place be maintained as case numbers decline to ensure eradication,” said their report, published after the cull began. The strategy of mass slaughter –
known as contiguous culling – sparked revulsion in the British public and prompted analyses of the methodology which led to it.
A 2011 paper, Destructive Tension: mathematics versus experience – the progress and control of the 2001 foot and mouth epidemic in Great Britain, found that the government ordered the destruction of millions of animals because of “severely flawed” modelling.
According to one of its authors – Dr Alex Donaldson, the former head of the Pirbright Laboratory at the Institute for Animal Health – Ferguson’s models made a “serious error” by “ignoring the species-composition of farms”, and the fact that the disease spread faster between some species than others.
The report stated: “The mathematical models were, at best, crude estimations that could not differentiate risk between farms, and, at worst, inaccurate representations of the epidemiology of FMD.”
An earlier report, in 2006 – Use and abuse of mathematical models: an illustration from the 2001 foot and mouth epidemic in the United Kingdom
– identified Prof Ferguson’s modelling as having been the biggest driver of government policy. The paper said that “the models were not fit for the purpose of predicting the course of the epidemic and the effects of control measures. The models also remain unvalidated. Their use in predicting the effects of control strategies was therefore imprudent.”
Last night, Prof Thrusfield said: “When we wrote those two review papers, we thought it would be a cautionary tale for the future if foot and mouth disease struck again. We didn’t think it would be a cautionary tale for a new plague in the human population – but of course the cautionary tale is fully valid. This is déjà vu.”
Prof Ferguson said of his modelling for FMD: “A number of factors go into deciding policy, of which science – particularly modelling – is only one. It is ludicrous to say now that our model changed government policy. A number of factors did.
“We were doing modelling in real time as the other groups were in 2001 – certainly the models weren’t 100 per cent right, certainly with limited data and limited time to do the work. But I think the broad conclusions reached were still valid.”
Of his work on BSE, in which he predicted a human death toll of between 50 and 150,000, Professor Ferguson said: “Yes, the range is wide, but it didn’t actually lead to any change in government policy.”
Others have directly criticised the methodology employed by Ferguson and his team in their coronavirus study. John Ioannidis, professor in disease prevention at Stanford University, said: “The Imperial College study has been done by a highly competent team of modellers. However, some of the major assumptions and estimates that are built in the calculations seem to be substantially inflated.”
Prof Ferguson said anyone who thought the coronavirus was akin to seasonal flu was “living in cloud cuckoo land”. He defended the conclusions reached “in terms of the overwhelming demand on healthcare systems imposed by this virus”.
He added: “It is ludicrous, frankly, to suggest that the severity of this virus is comparable to seasonal flu – ludicrous and dangerous. People who are doing so have not analysed the data in any level
of detail.”