In a new study unveiled on Monday, researchers at CSIRO, Australia’s largest federal research agency, have found that the virus that causes Covid-19 can survive and remain dangerous for up to 28 days on many surfaces of life. standard, such as smartphones, banknotes or self-service checkout screens in supermarkets.
So far, studies, notably carried out by the US CDC, had estimated that the virus could only survive for “a short period” on surfaces contaminated by droplets projected by an infected person. “Our results demonstrate that SARS CoV-2 can remain infectious for much longer periods of time than is generally considered possible,” write the Australian researchers, who hope their findings will “improve procedures to mitigate the disease. risks to prevent the spread of COVID-19 ”.
“Extremely robust” at 20 ° C
To obtain these results, CSIRO measured the survival rate over time of the virus on six different surfaces exposed, in the laboratory, to different temperatures of 20ºC, 30ºC and 40ºC but at a fixed humidity level of 50%. They concluded that the life expectancy of the virus shortened with rising ambient temperatures. It thus barely survives 24 hours on glass, paper or polymer banknotes exposed to a temperature of 40ºC. At this temperature, it is no longer active after 16 hours on cotton.
On the other hand, the virus can, according to the study, be shown to be “extremely robust” in an ambient temperature maintained at 20ºC. In the laboratory, it remains infectious for 28 days on smooth non-porous surfaces such as paper, vinyl, glass, steel and polymer banknotes.
By comparison, the influenza virus only survives 17 days on these same surfaces. “This confirms that it is important to wash your hands and disinfect yourself when possible, and also to wipe down surfaces that may be in contact with the virus”, summed up Shane Riddell to Reuters. one of the authors of the CSIRO study. In particular, he points to self-service checkouts in supermarkets, ticket machine screens and airport check-in kiosks.
In order not to panic public opinion, the Australian researchers point out that the spread of the virus is done mainly by infected droplets which are airborne and they also note that their work is carried out under very strict laboratory conditions and in the dark to avoid disturbances by UV light.
If they admit that this virus survival is therefore certainly shorter in real life, they believe that their conclusions could however explain the appearance of large foci of infections in cool or cold spaces such as slaughterhouses , where employees work on steel surfaces.