Fluid dynamics of COVID-19 airborne infection suggests urgent data for a scientific design of social distancing
Abstract The COVID-19 pandemic is largely caused by airborne transmission, a phenomenon that rapidly gained the attention of the scientific community. Social distancing is of paramount importance to limit the spread of the disease, but to design social distancing rules on a scientific basis the proc...
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Main Authors: | , , , , |
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Format: | article |
Language: | EN |
Published: |
Nature Portfolio
2020
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Subjects: | |
Online Access: | https://doaj.org/article/6008c60c8fca464f86c5cfacefa21eb6 |
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Summary: | Abstract The COVID-19 pandemic is largely caused by airborne transmission, a phenomenon that rapidly gained the attention of the scientific community. Social distancing is of paramount importance to limit the spread of the disease, but to design social distancing rules on a scientific basis the process of dispersal of virus-containing respiratory droplets must be understood. Here, we demonstrate that available knowledge is largely inadequate to make predictions on the reach of infectious droplets emitted during a cough and on their infectious potential. We follow the position and evaporation of thousands of respiratory droplets by massive state-of-the-art numerical simulations of the airflow caused by a typical cough. We find that different initial distributions of droplet size taken from literature and different ambient relative humidity lead to opposite conclusions: (1) most versus none of the viral content settles in the first 1–2 m; (2) viruses are carried entirely on dry nuclei versus on liquid droplets; (3) small droplets travel less than $$2.5\,{\mathrm{m}}$$ 2.5 m versus more than $$7.5\,{\mathrm{m}}$$ 7.5 m . We point to two key issues that need to be addressed urgently in order to provide a scientific foundation to social distancing rules: (I1) a careful characterisation of the initial distribution of droplet sizes; (I2) the infectious potential of viruses carried on dry nuclei versus liquid droplets. |
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