Transmission of the coronavirus is caused by the expulsion of infected droplets. These micro-particles can therefore be deposited on surfaces and contaminate them. In a new study, Australian researchers set out to find out how long the virus survives on materials.
The coronavirus Sars-Cov-2 is spread from an infected person to another through droplets of saliva or through infected objects. In a recent study, Australian National Science Agency (CSIRO) investigated the behavior of the virus on different surfaces. The work has been published in le Journal of Medical Virology.
During research, scientists observed the survival rate of the Covid-19 on many surfaces such as steel, glass, vinyl, paper banknotes and cotton fabrics. During the study, they exposed the Sars-Cov-2 to different temperatures.
Results: when exposed to 20 ° C, infectious material can survive for up to 28 days on smooth surfaces such as the steel of a doorknob or the glass screen of a cell phone. According to scientists, no trace of the virus was detected after 14 days on cotton fabrics.
However, as soon as the temperature rises, the virus becomes less robust. Australian researchers have therefore noticed that at 30 ° C the virus can withstand seven days on steel, silver or glass. At 40 ° C, the coronavirus stays less than 24 hours on these three materials.
How long does the coronavirus last in the air?
To refine their knowledge of Covid-19, American researchers from the National Institutes of Health have also attempted to estimate the lifespan of the virus on surfaces and in the air. Their research was disseminated on the scientific prepublication site medRxiv.
For the purposes of the study, they analyzed the resistance of coronavirus Sars-Cov-2 in the air, but also on surfaces such as copper, steel, carton and plastic. Materials that can be found on door handles, food packaging or even packages.
The virus could survive for up to 4 hours on copper, up to 24 hours on cardboard and up to 3 days on plastic and steel, although its overall concentration dropped considerably by that time. In the air, the virus could stay suspended for three hours.
The presence of the coronavirus does not necessarily mean infection
Findings to be handled with care, because researchers do not yet know exactly “how much virus is really needed to infect a human being, or whether the virus is easily transferable from a box to a hand when you touch a package for example”, as Dylan Morris, co-author of the study, explains.
Scientists give another precision: it is not because the coronavirus is found on certain surfaces or in the air after a few hours that it is still able to infect someone. “We are in no way claiming that there is transmission of the virus in the air”, adds Neeltje van Doremalen, co-author of the study.
Coronavirus: the importance of barrier gestures and disinfection
If these results must be confirmed, they reinforce, if necessary, the importance of applying barrier gestures, namely:
- wash one’s hands very regularly;
- cough or sneeze into the crease of their elbow;
- do not shake hands or kiss;
- use disposable tissues and throw them away immediately;
- avoid gatherings, limit movement and contact.
Dr Angela Rasmussen reacted on Twitter to this research. “This information is useful to the public because it can help us take precautions to avoid exposure / transmission.”, she explains. His advices ?
- wipe off and disinfect shared surfaces (door handles, counters, etc.);
- wash your hands frequently;
- do not touch your face;
- practice social distancing.
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