Medical Research Council - London Institute of Medical Sciences

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Say Don't Spray

Evidence that normal speaking causes airborne virus transmission

03 June 2020

Say Don't Spray

How many times have we said “stay safe” or “stay healthy” in the past few months? Alongside the combined efforts of health authorities, doctors and healthcare scientists, our social interactions play a crucial part in limiting the spread of COVID-19 (SARS-CoV-2). While social distancing precautions may at times seem impractical or abstract, recent studies show that even a simple conversation in a confined space may be enough to transmit viral particles. Aerobiologists used lasers to watch and measure these fluid droplets spraying from a mouth saying “Stay healthy”, finding similarities to the spray flung out by a sneeze or cough. The scientists estimate the size of the droplets from how quickly they evaporate; predicting speech droplets big enough to carry viral particles may linger in the air for many minutes during a conversation, and supporting the use of masks and distancing advice while research continues.

Written by John Ankers

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