RESEARCHERS at CSIRO have found that the COVID virus can survive for up to 28 days on common surfaces including stainless steel, banknotes and glass – up to ten days longer than the common influenza virus on some surfaces.
The research, undertaken at the Australian Centre for Disease Preparedness (ACDP) in Geelong, found that the virus:
- 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
- Survived longer on paper banknotes than plastic banknotes.
The research may help to explain the apparent persistence and spread of COVID in cool environments with high lipid or protein contamination, such as meat processing facilities, and how this risk might be better addressed, researchers said.
CSIRO chief executive Dr Larry Marshall said establishing how long the virus really remains viable on surfaces enabled scientists to more accurately predict and mitigate its spread, and do a better job of protecting people.
“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,” Dr Marshall said.
“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 investigated five surfaces at three temperatures (see graphic below).
Dr Debbie Eagles is deputy director of CSIRO’s Australian Centre for Disease Preparedness, which has been working on both understanding the virus and testing a potential vaccine.
“Our results show that COVID can remain infectious on surfaces for long periods of time, reinforcing the need for good practices such as regular handwashing and cleaning surfaces,” Dr Eagles said.
“At 20 degrees Celsius, which is about room temperature, we found that the virus was extremely robust, surviving for 28 days on smooth surfaces such as glass 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.”
Results from the study, The effect of temperature on persistence of SARS-CoV-2 on common surfaces was published in Virology Journal. Click here to view the study. (https://rdcu.be/b8dik).
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 and 40 degrees Celsius, with survival times decreasing as the temperature increased.
Droplets of COVID virus were applied to test surfaces at the Australian Centre for Disease Preparedness at Geelong.
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.
“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,” Dr Eagles said.
Director of ACDP, Professor Trevor Drew, said 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,” Prof Drew said.
The presence of proteins and fats could also significantly increase virus survival times.
Surface survivability research builds on CSIRO’s other COVID work, including vaccine testing, wastewater testing, Personal Protective Equipment manufacture and accreditation, and big data dashboards supporting each state.
In partnership with the Australian Department of Defence, CSIRO undertook the studies in collaboration with the Five Nation Research and Development Council, which comprises representatives from the UK, US, Canada, New Zealand and Australia.
Each country is conducting research on different aspects of virus survivability with the results shared as they become available.
Product Hygiene Indicator reform – microbiological testing
The Product Hygiene Indicator (PHI) is a monitoring system that operates at all Australian export processing supplying major red meat markets. This reform will involve moving the focus of microbiological monitoring from purely carcase monitoring activity, by introducing additional microbial monitoring on primal meat and offal.
It is also proposed to remove Salmonella carcase monitoring due to an ongoing industry history of good compliance. However Salmonella would still be monitored as part of the routine carcase baseline surveys.
The PHI reform is in line with a 2019 national scientific review conducted by the South Australian Research and Development Institute, which identified areas for improvement without impacting food safety outcomes.