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Modelling study suggests breathing and coughing can release large amounts of COVID-19

3 August, 2020  

In a new mathematical modelling study, researchers from the Swiss Centre for Occupational and Environmental Health suggest that spending time in a small room with a COVID-19 super spreader poses a risk of infection and that this risk is further heightened if they are coughing.

The researchers modelled the impact of viral transmission for super spreaders, which are defined as those who emit a large number of microdroplets (and thus high amounts of COVID-19) during both coughing and normal breathing. For super spreaders, while most of the viral particles are carried in airborne microdroplets which deposit rapidly, there was estimated to be an portion of smaller particles which can remain in the air for extended period of time and these particles were very effective at reaching the lungs. Hence, there is a greater risk of infection for a person spending an extended period of time in the same room as a super spreader, especially if the cough, even when observing appropriate social distancing in the room.

In contrast, the modelling estimated that for infected individuals who are not super spreaders, that is, those with a typical viral load, the risk of infection is low when they are breathing normally and maintaining social distancing. Fortunately, the modelling suggests there are a small number of super spreaders but because these individuals are impossible to identify, strict respiratory protection is recommended when spending time in a small room.

Riediker M, Tsai DH. Estimation of viral aerosol emissions from simulated individuals with asymptomatic to moderate coronavirus disease 2019. JAMA Netw Open 2020;3(7):e2013807. doi:10.1001/jamanetworkopen.2020.13807