But scientists who have delved into the work have found errors that they feel undermine the results to the point that they cannot be invoked when scientists and ministers decide what constitutes a safe physical distance.
“Analysis of the risk of infection at one meter against two meters should be treated with great caution,” said Professor David Spiegelhalter, statistician at the University of Cambridge, who participated in the government’s scientific advisory group for emergencies. “I am very suspicious of it. ”
Professor Kevin McConway, an applied statistician at Open University, went further and called the analysis inappropriate. He said the work “should not be used in arguments about how the risk of infection is higher at a minimum distance of one meter from two meters”.
The study published in The Lancet is the last to be criticized by experts who fear that in the midst of the pandemic, some research papers will be written, reviewed and published too quickly for sufficient quality checks to be carried out. Earlier this month, The Lancet and another elite publication, the New England Journal of Medicine, were forced to withdraw studies on coronaviruses after reports of flaws appeared.
Doubts about the WHO study emerged when Boris Johnson announced an official review of the two-meter physical distance rule, which is expected to be published by July 4, the earliest date pubs and restaurants could reopen in England. In recent weeks, Johnson has come under intense pressure from Conservative MPs to soften the advice to help businesses, particularly in the hotel sector.
Conducted by researchers from McMaster University in Ontario, the WHO report has combined previously published study data to estimate the risk of being infected with coronavirus at different distances. He also looked at how face masks and eye protection could help prevent the spread of disease.
But in the analysis, the authors assume that the proportional impact on the risk of going from two meters to one meter is the same as going from one meter to zero. “They force the proportional adjustment to be the same,” Spiegelhalter told the Guardian.
McConway believes there is a more fundamental problem in how the risks of infection at different distances are compared in the study. He said: “The method of comparing different distances in the document is inappropriate to tell you exactly how the risk at a minimum distance of two meters compares to a minimum distance of one meter. It does not support, and should not be used in, arguments about how the risk is greater with a limit of one meter compared to a limit of two meters.