SARS-Cov-2 can survive up to 28 days on surfaces
CSIRO researchers have found that SARS-CoV-2, the virus responsible for COVID-19, can survive for up to 28 days on common surfaces including banknotes, glass — such as that found on mobile phone screens — and stainless steel.
The research was undertaken at the Australian Centre for Disease Preparedness (ACDP), which has been working on both understanding the virus and testing a potential vaccine. It involved drying virus samples in artificial mucus on different surfaces, at concentrations similar to those reported in samples from infected patients, and then reisolating the virus over a month. Experiments were carried out at 20, 30 and 40°C.
The results of the research, as published in Virology Journal, found that SARS-CoV-2:
- survived longer at lower temperatures;
- tended to survive longer on non-porous or smooth surfaces such as glass, stainless steel and vinyl, compared to porous complex surfaces such as cotton; and
- survived longer on paper banknotes than plastic banknotes.
The study was carried out in the dark, to remove the effect of UV light as research has demonstrated direct sunlight can rapidly inactivate the virus.
“Our results show that SARS-CoV-2 can remain infectious on surfaces for long periods of time, reinforcing the need for good practices such as regular handwashing and cleaning surfaces,” said ACDP Deputy Director Dr Debbie Eagles.
“At 20°C, which is about room temperature, we found that the virus was extremely robust, surviving for 28 days on smooth surfaces such as glass found on mobile phone screens and plastic banknotes.
“For context, similar experiments for Influenza A have found that it survived on surfaces for 17 days, which highlights just how resilient SARS-CoV-2 is.
“While the precise role of surface transmission, the degree of surface contact and the amount of virus required for infection is yet to be determined, establishing how long this virus remains viable on surfaces is critical for developing risk mitigation strategies in high contact areas.”
ACDP Director Professor Trevor Drew said many viruses remain viable on surfaces outside their host, noting, “How long they can survive and remain infectious depends on the type of virus, quantity, the surface, environmental conditions and how it’s deposited — for example, touch vs droplets emitted by coughing.
“Proteins and fats in body fluids can also significantly increase virus survival times.
“The research may also help to explain the apparent persistence and spread of SARS-CoV-2 in cool environments with high lipid or protein contamination, such as meat processing facilities.”
CSIRO Chief Executive Dr Larry Marshall concluded, “Establishing how long the virus really remains viable on surfaces enables us to more accurately predict and mitigate its spread, and do a better job of protecting our people.”
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