From the moment you turn off your morning alarm, to the time you hit the pillow, your life is full of surfaces. Swiping through your phone, opening doors, putting in your PIN – there are many you don’t think twice about touching.
But SARS-CoV-2, the virus that causes COVID-19, will likely change the way we all think about, and interact with, surfaces forever. Our peer-reviewed study published in Virology Journal reveals new information about the virus and how it behaves on surfaces.
Understanding SARS-CoV-2 on surfaces
From analysing sewage to testing face masks, our research has been contributing to the global battle against COVID-19.
At this stage of the pandemic, researchers do not fully understand the role contaminated surfaces play in the transmission of SARS-CoV-2. To improve our understanding of how this new virus behaves, our researchers studied the survival rates of infectious SARS-CoV-2, dried in an artificial mucous solution, on six common surfaces.
We conducted the experiment at three different temperatures, 200C, 300C and 400C, with the relative humidity kept at 50 per cent. The surfaces used in the study were stainless steel, glass, vinyl, paper and polymer banknotes, and cotton cloth. These are examples of high contact surface areas such as glass on touchscreens and stainless steel doorknobs.
A droplet of fluid containing the virus at concentrations similar to levels observed in infected patients was dried on multiple small test surfaces and left for up to 28 days. At various time periods, the virus was recovered and placed in tissue culture cells to observe if any infectious virus remained.
Impact of temperature on virus
At 20°C, the virus was extremely robust. We were able to recover infectious material after 28 days from the smooth (non-porous) surfaces. These are stainless steel, glass, vinyl and paper and polymer banknotes.
The length of time infectious virus was able to survive on the porous material (cotton cloth) was much shorter. On cloth, we were unable to detect any viable virus past 14 days.
At 30°C infectious virus did not survive beyond seven days on stainless steel, money (polymer banknotes) and glass. However, on vinyl and cotton cloth, infectious material was not detectable beyond three days.
At 40°C virus was inactivated much faster. Infectious SARS-CoV-2 was detectable for less than 16 hours for cotton cloth. While on glass, paper and polymer notes, and stainless steel it was detectable for up to 24 hours, and 48 hours for vinyl.
How many particles can cause an infection?
It generally takes more than one virus particle to infect a person and make them sick. We call the number of virus particles that can cause infection the “infectious dose”. This dosage differs between different viruses and is usually quite large.
Researchers do not yet know the infectious dose of SARS-CoV-2. But, from our knowledge of related viruses, we estimate it is around 300 particles. If the virus was placed (on smooth surfaces) at standard mucus concentrations of an infected person, enough virus would easily survive for two weeks to be able to infect another person.
Further research on this topic is necessary. However, our findings indicate the 28-day sample would not contain enough viable virus to infect a person.
Whether virus particles on a surface can infect someone is dependent on several conditions. Outside of the body, SARS-CoV-2 virus particles gradually become inactive over time. The time it takes for viruses to naturally inactivate depends on many factors. The makeup of the virus itself, the type of surface it is on and whether the virus is liquid or dried can impact the time it remains viable. Environmental conditions such as temperature, exposure to sunlight and humidity also play a part.
Cash or card? A droplet of liquid containing the SARS-CoV-2 virus on a $5 note.
How virus transmission works
In general, we know people deposit viruses onto surfaces by coughing or sneezing. They are also readily transferred between contaminated skin and surfaces.
The results from our study confirm that high-contact surfaces may pose a risk. These are the type of surfaces that have a significant number of different people touching them each day. They include bank ATMs, handrails, door handles, elevator buttons, supermarket self-serve check-outs and money.
While we can’t yet answer the likelihood of developing COVID-19 from surfaces, we do know the SARS-CoV-2 virus can’t penetrate skin. To catch the disease, you would first need to introduce the virus into your mouth, nose or eyes. Our findings reinforce the message that you should avoid touching your eyes, nose and mouth and keep washing your hands. It’s also important to be careful when removing facemasks as the virus can survive on the outside where you could transfer it to your hands.
Building our understanding of COVID-19
Although we still don’t know how much virus it takes to infect someone, our research is forming a better understanding of how this new virus behaves.
Our knowledge that the virus survives longer at colder temperatures may also help to explain the spread of SARS-CoV-2 in environments such as meat processing facilities.
Our research will help to provide insight into the risks associated with COVID-19. And can help with the development of procedures for minimising the chances of virus spread via surfaces.
12th October 2020 at 4:00 pm
Once again scare tactics – so what if its survives, what level will result in infection? – can someone catch it from these surfaces – other studies have been done using other viruses and COVID 4 months ago, this is not new – the same results shown above – see the CDC research – why the hell would you write an article like this with no credible evidence. It like making the public wear masks in Victoria when in Victoria 1,300 health workers caught the Virus and they were wearing proper masks (this evidence suggests its a waste of time).
With all the unreliable studies and claims, an research (about COVID) that cannot be validated by test (has some one caught a virus from these surfaces? ), why would people trust the scientific community.
13th October 2020 at 2:39 pm
Hi Tim, thanks for your comment.
This is a new virus and it takes time to fully understand how it can behave. The purpose of this study was to measure the survival of the virus at different temperatures in the mucous-type matrix that is present in the lungs and upper respiratory tract of people. It is important that these initial studies are conducted in controlled conditions – otherwise it can be difficult to determine which factor is influencing survival time. Our findings reinforce the ongoing importance of washing hands, using hand gels/wipes when out in public. Avoid touching common surfaces whenever possible and don’t put your fingers in your mouth or rub your eyes.
12th October 2020 at 12:53 pm
s.o.p. means?? Is it ‘standard procedure’? I am not a bureaucrat and speak English.
12th October 2020 at 12:51 pm
Some information on ways to clean the surfaces..??
Is it possible with ordinary cleaning?Hot soapy water at 40′? Is wiping with alcohol and throwing away the paper cloth enough?
Obviously clothing can be washed in hot water, but we have known that already,
Bank notes can be cleaned when returned to the bank and we are all using cards or phones to pay I hope. We need to clean the cards and phones and keep them in our pockets rather than leather wallet.
WHAT are you all doing to protect yourselves?
12th October 2020 at 2:39 pm
Hi Dale, thanks for your comment. The Department of Health is best placed to offer advice on protecting yourself from COVID-19. They have information available on their website here: https://www.health.gov.au/news/health-alerts/novel-coronavirus-2019-ncov-health-alert/how-to-protect-yourself-and-others-from-coronavirus-covid-19
12th October 2020 at 11:59 am
Putting this info front & centre might help reverse the decline in the attention people are giving to hygiene in public places. Handwashing & sanitizers should be s.o.p. in shops, supermarkets etc but a lot of people no longer seem to care enough to take the few seconds required.
I’d like to see a reliable study on impact of “covid sanitation” & reduced greeting contact (hugs, kisses & handshakes) on prevalence of other common bugs like colds & flu. Been a very bug free winter & spring here in Noosa hinterland but could be coincidence, and might not be same across other parts of the country.
12th October 2020 at 10:24 am
This is the sort of distinct information the News should be reinforcing and stop worrying about numbers and statistics.
Pass this on to the government – let them know and then let the public know you gave it to them. Force the Politicians into affirmative action. Face masks, face shields and gloves should be mandatory in public spaces and self isolation for ALL Victorians is the only way the spread will stop. Ask New Zealand. Ask China. They endured it. Surely Australians can too.