The virus that causes COVID-19 can last longer than previously thought on hard surfaces such as stainless steel, plastic banknotes and the glass on mobile phone screens, according to the latest research from the CSIRO.
Research undertaken at the Australian Centre for Disease Preparedness (ACDP) in Geelong and published in the Virology Journal, found SARS-CoV-2 can survive for up to 28 days on such common surfaces.
The virus endures for longer on smoother surfaces than softer ones such as cotton, and also survives better at lower temperatures.
CSIRO chief executive Dr Larry Marshall says surface survivability research builds on the national science agency's other COVID-19 work, including vaccine testing, wastewater testing, personal protective equipment (PPE) manufacture and accreditation, and big data dashboards supporting each state.
"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," says Dr Marshall.
ACDP deputy director Dr Debbie Eagles says the fact SARS-CoV-2 can remain infectious on surfaces for long periods of time reinforces he need for good practices such as regular handwashing and cleaning surfaces.
"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," says Dr Eagles.
"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."
The research involved drying virus in an artificial mucus on different surfaces, at concentrations similar to those reported in samples from infected patients and then re-isolating the virus over a month. Further experiments were carried out at 30°C and 40°C, with survival times decreasing as the temperature increased.
"Together, we hope this suite of solutions from science will break down the barriers between us, and shift focus to dealing with specific virus hotspots so we can get the economy back on track," says Dr Eagles.
"We can only defeat this virus as Team Australia with the best Australian science, working alongside industry, government, research and the Australian community."
The study was also carried out in the dark, to remove the effect of UV light as research has demonstrated direct sunlight can rapidly inactivate the virus.
"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," she says.
ACDP director, professor Trevor Drew, says many viruses remained viable on surfaces outside their host.
"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," says Dr Drew.
"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 and how we might better address that risk."
Updated at 10am AEDT on 12 October 2020.
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