In a new study, researchers found that face masks can help prevent the spread of COVID-19 among folks trapped in a room with an infected “super spreader”.
The research was conducted by a team from the Swiss Centre for Occupational and Environmental Health in Winterthur.
Most infected people with a typical COVID viral load don’t flood the air with coronavirus-infected respiratory droplets, and the risk of catching the virus from them tends to be low, estimates show.
But the current study shows a severely infected person who’s coughing frequently can fill a poorly ventilated room with as many as 7.4 million copies of the coronavirus for every cubic meter of air.
The team says that individuals may be at risk of infection if they spend more than a few minutes in a small room with a person who is infected with COVID-19 and has a high viral load.
And the findings highlight the importance of wearing a mask. Wearing a mask clearly helps, and it will diminish the capacity of these super-spreaders to spread as much.
In this study, the researchers gathered data from a handful of prior studies that tracked how much coronavirus the average infected person will emit by breathing normally, as well as the virus released by a very sick person who’s coughing frequently.
The team then used a mathematical model to estimate how much virus either a low- or high-emitting patient is likely to release into the air of a closed room.
They found a COVID-19 patient with a high viral load could be expected to release a large amount of virus into the air, especially when they are coughing.
These so-called super-spreaders aren’t very common, but if they are engaged in activities like loud speaking or singing, their viral emissions can increase by 1 to 2 orders of magnitude.
As far as the risk to folks sharing the room with COVID-19 patients, people who are at rest tend to breathe in about a half a cubic meter of air every hour.
Thus, a person spending time in a room with an individual emitting at a typical rate and breathing normally has the chance of inhaling only a few copies of the virus when keeping a distance from that person.
However, people who are exercising might breathe up to six times as much air as a person at rest, gulping down several cubic meters of air per hour.
These people clearly are at higher risk, particularly if they’re in a small room with a person who’s coughing.
The team says mask-wearing would prevent super spreaders from filling the air with the virus.
People have to understand they’re not wearing the mask for themselves. They’re wearing the mask for people that are unfortunately not capable of protecting themselves.
One author of the study is Michael Riediker.
The study is published in the journal JAMA Network Open.
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