How one cough can infect a supermarket
A horrifying video using 3D modelling has shown how quickly coronavirus can spread indoors if a person infected with the potentially-deadly disease coughs.
Researchers from four research organisations in Finland have developed a computer model that demonstrates how the virus moves and spreads through the air, illustrating the importance of avoiding busy and crowded areas and upholding social distancing measures.
Released by Aalto University, the video shows what happens if a COVID-19 infected person coughs inside a supermarket with aisles and a typical indoor ventilation system.
The virus, which has infected more than 1.5 million people around the world and killed close to 100,000, is spread from person to person through small droplets from the nose or the mouth, released when a person with COVID-19 coughs or exhales.
The droplets land on objects and surfaces around the person - and the disease is then contracted by other people who either breathe in droplets from the infected person when they cough or exhale, or by touching these objects or surfaces, then touch their nose, eyes or mouth.
The modelling by the researchers shows how particles spread outside the immediate vicinity of the coughing person.
While the particles eventually dilute - as the amount of "viable virus" immediately decreases once it leaves the body - it can take several minutes for this to happen, meaning others can still be easily exposed.
"Someone infected by the coronavirus can cough and walk away, but then leave behind extremely small aerosol particles carrying the coronavirus," Aalto University assistant professor Ville Vuorinen explained.
"These particles could then end up in the respiratory tract of others in the vicinity."
The research demonstrates the importance of staying home if you're feeling unwell, practising good respiratory hygiene (coughing or sneezing into a tissue or your elbow), and maintaining good hand and oral hygiene.
It also illustrates why people should avoid busy indoor areas - like grocery stores and public transport - and why we should ensure we're abiding by social distancing measures.
With grocery stores preparing for the usual Easter long weekend influx of customers, Australia's major supermarkets Coles and Woolworths have put additional measures in place to prevent shops becoming too crowded.
Woolworths announced last Sunday it "will be limiting the number of customers allowed in store from time to time", with managing director Claire Peters saying the number of customers allowed into each store at any one time would be dependent on its size.
Shoppers outside will need to wait in cordoned-off queues, with security guards and police officers expected to manage the lines at peak times and enforce the 1.5 metre social-distancing rules.
At Coles, similar measures will be taken, with staff at store entrances to provide assistance and let customers know when they're allowed to come in.
Originally published as How one cough can infect a supermarket