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6-feet rule virtually ineffective at preventing COVID spread indoors: MIT study

Researchers Martin Bazant and John Bush say, in most cases, exposure to the airborne virus is not prevented by social distancing
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Voters socially distance while waiting in line. (Curtis Compton/AP)

According to a new study from researchers at the Massachusetts Institute of Technology, staying six feet away from others does little to curb the spread of COVID-19 indoors.

Released Tuesday (April 27), “A Guideline to Limit Indoor Airborne Transmission of COVID-19” suggests virus-laden respiratory droplets emitted from an infected person pose more of an exposure risk than commonplace social distancing rules mitigate.

That’s according to mathematicians Martin Bazant and John Bush.

The duo generated a formula to simulate rooms where respiratory droplets expelled from an infected person wearing a mask were “well-mixed” or evenly spread throughout a room.

Depending on variables – including the size of the space, number of people, type of activity, whether masks are worn and ventilation or filtration measures – the risk of COVID-19 exposure was reduced or heightened.

In calmer environments with few people, the study found droplets carrying the virus fell to the ground faster than in high-activity rooms where particles stayed suspended in the air, longer.

READ MORE: Feds launch ad campaign urging social distancing, hygiene during COVID-19 crisis

“To minimize the risk of infection, one should avoid spending extended periods in highly populated areas,” concluded Bazant and Bush in the study.

“One is safer in rooms with large volume and high ventilation rates. One is at greater risk in rooms where people are exerting themselves in such a way as to increase their respiration rate and pathogen output, for example, by exercising, singing, or shouting.”

Overall, mask-wearing was found to be the best way to limit both short-range and overall airborne transmission of COVID-19, followed by sufficient ventilation and filtration.

Bazant and Bush also created a website allowing users to use their formula to determine for themselves how best to avoid catching COVID-19 indoors.

On it, the researchers stated, “while public health organizations are beginning to acknowledge airborne transmission, they have yet to provide a safety guideline that incorporates all the relevant variables.”

RELATED: 2-metre eagle wingspan signage reminds folks in B.C. city to practise social distancing



sarah.grochowski@bpdigital.ca

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