Published: 12 June 2020
A study supported by the NIHR Imperial Biomedical Research Centre and the NIHR Health Protection Research Unit in Modelling Methodology estimates national lockdowns have saved more than three million lives in Europe.
From 2-29 March 2020, European countries began implementing unprecedented interventions such as social distancing, school closures and national lockdowns to control COVID-19. Understanding the effectiveness of these measures is important because these strategies may be needed to keep COVID-19 transmission under control.
The study assessed the impact of restrictions in 11 European countries - Austria, Belgium, Denmark, France, Germany, Italy, Norway, Spain, Sweden, Switzerland and the UK - up to the beginning of May.
The team estimated that by 4 May 2020, between 12 and 15 million individuals in these countries had been infected with COVID-19 (3.2% to 4% of the population, with large country-to-country fluctuations).
They then compared the number of observed deaths against those predicted by their model if there had been no lockdown measures. This analysis estimated 3.2 million people would have died if not for measures such as telling people to stay at home.
They calculate that the reproduction number has dropped to below one as a result of the interventions, decreasing by an average of 82%, although the values vary from country to country. For all 11 countries analysed, the current interventions have been sufficient to drive the reproduction number below one and achieve epidemic control.
The study, published in the journal 'Nature', calculated infection levels retrospectively by analysing reported deaths. Although death data may be subject to under or misreporting, it is considered more reliable than other data, and can be used to infer changes in the course of the COVID-19 epidemic as a result of lockdown interventions.
Dr Samir Bhatt, from Imperial College London, said: “This data suggests that without any interventions, such as lockdown and school closures, there could have been many more deaths from COVID-19. The rate of transmission has declined from high levels to ones under control in all European countries we study.
“Our analysis also suggests far more infections in these European countries than previously estimated. Careful consideration should now be given to the continued measures that are needed to keep COVID-19 transmission under control.”