Neil Ferguson talks modelling, lockdown and scientific advice with MPs

Imperial’s Neil Ferguson told MPs that introducing lockdown measures in the UK a week earlier would have reduced deaths by at least half.

Speaking at the Science and Technology Committee, Professor Ferguson, said: “The epidemic was doubling every three to four days before lockdown interventions were introduced. So had we introduced lockdown measures a week earlier, we would have reduced the final death toll by at least a half."

Professor Ferguson, Director of the Jameel Institute (J-IDEA) and MRC-GIDA, added that the measures were warranted based on what was known about transmission and fatalities at the time.

Rapid response: Modelling in real-time

Professor Ferguson explained that quality assurance of papers presented at SAGE, which were produced in real-time, was ensured by comparing results between different models.

He said: "Models codify assumptions and knowledge in a precise and testable way, it is only problematic if this is taken as a literal view of the truth."

He explained that there was not one model responsible for informing the lockdown decision.

Professor Ferguson also highlighted:

• The important role of modelling in informing scientific advice during the pandemic
• Modelling is one of multiple scientific inputs informing policy decision making
• How science gives insight into the potential consequences of policy options, but does not determine which policies are adopted
• Until vaccines are available, transmission will need to be monitored and new outbreaks responded to rapidly. 

UK infection levels

Professor Ferguson reported that around eight per cent of people in England have now been infected by the virus, according to serological surveys conducted by Public Health England.

Professor Ferguson also explained that many more infection cases had arrived in the UK from Italy and Spain than had first been anticipated.

He said: "Just before lockdown happened, the first two weeks of March, we probably had around 1,500 to 2,000 infections imported from Italy and Spain which we just hadn’t seen in the surveillance data. So there is much heavier seeding than we’d expected"

He also explained that in early March, his team was working on the assumption that around two-thirds of infections were being missed at UK borders when in reality it was closer to 90 per cent.

Care home outbreaks

Professor Ferguson added that his team's work had expected that care homes - where around half of all COVID-19 deaths have occurred - would have been better shielded from infection than they actually were.

He said that SAGE had anticipated the risk to care homes, but added that they could only be protected through extensive testing, which was a concern at the time and was not available at the level that was required. 

Back in March, Professor Ferguson gave evidence to the House of Commons Science and Technology Committee, where he told MPs that the current UK lockdown could keep the coronavirus outbreak at manageable levels and the NHS would be able to cope if strict measures continued to be followed.

Last week he gave evidence to the House of Lords Science and Technology Committee where he said he expected levels of transmission and numbers of cases will remain relatively flat between now and September.

Lockdown may have prevented millions of deaths

This week Imperial’s Covid-19 Response Team published research in Nature, which found that large-scale lockdowns and school closures in Europe may have prevented 3.1m deaths.

The team, from the MRC Centre for Global Infectious Disease Analysis, Jameel Institute (J-IDEA), and Imperial's Department of Mathematics, estimated reductions in transmission based on combined data from 11 European countries up to early May 2020. 

Professor Ferguson told the Committee that there is overwhelming evidence that interventions including lockdown have helped to reduce mortality.