Two-metre coronavirus social distancing rule ‘based on outdated science’, claim academics

Two-metre social distancing
Academics say a blanket two-metre rule is not necessarily the best course of action. Credit: PA

Rules on social distancing to curb the spread of coronavirus are based on “outdated science”, a group of academics have said.

Instead of a one-size-fits-all approach to social distancing, there should be “graded recommendations” for different distancing rules in different settings, they argued.

Writing in The BMJ, the team of researchers said this would provider greater protection for people in high risk settings and greater freedoms for people in lower risk settings.

They added that this would “potentially enable a return towards normality in some aspects of social and economic life”.

Distancing rules should take account of multiple factors that affect risk, including type of activity, indoor versus outdoor settings, level of ventilation and whether face coverings are worn, they said.

Whether or not people are wearing face coverings should be taken in to account, academics say. Credit: PA

Other important factors include duration of exposure, susceptibility of an individual to infection and viral load of the transmitter, they said.

They wrote that some of the research which points towards two metres being the optimal safe distance was first published in 1897.

And research from the 1940s is “entrenched” in the assumed scientific basis of the one to two metre rules to prevent coronavirus spread, despite “limitations in accuracy” of the early studies, they wrote.

Newer studies have found that in certain circumstances, droplets from a forceful sneeze or cough could spread up to eight metres.

Droplets from a sneeze can spread up to eight metres. Credit: PA

Meanwhile they argue that much of the research is based on droplet size without accounting for exhaled air.

In reality transmission is much more complex, they wrote.

“Current rules on safe physical distancing are based on outdated science,” according to Nicholas Jones,from Oxford University’s Nuffield Department of Primary Care and colleagues.

“Distribution of viral particles is affected by numerous factors, including air flow.

“Evidence suggests Sars-CoV-2 may travel more than two metres through activities such as coughing and shouting.

“Rules on distancing should reflect the multiple factors that affect risk, including ventilation, occupancy, and exposure time.”

The authors called for more work to develop solutions to examine appropriate distances for people in different settings.

They conclude: “Physical distancing should be seen as only one part of a wider public health approach to containing the Covid-19 pandemic.

“It needs to be implemented alongside combined strategies of people-air-surface-space management, including hand hygiene, cleaning, occupancy and indoor space and air managements, and appropriate protective equipment, such as masks, for the setting.”