A new study out of Australia found that the coronavirus can survive on common surfaces such as money, phone screens and stainless steel for about a month in room temperature conditions — a time frame that surpasses those from other studies.
The coronavirus was also found to last 10 days longer on some surfaces than influenza, the virus that causes the seasonal flu.
Researchers from CSIRO, Australia’s national science agency, said their findings add more evidence to the importance of washing your hands and properly disinfecting surfaces to prevent further spread of SARS-CoV-2, the virus that causes COVID-19.
The study was published Oct. 7 in the Virology Journal.
“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,” study co-author Dr. Debbie Eagles, deputy director of the Australian Centre for Disease Preparedness (ACDP), said in a news release.
Past research has shown that the coronavirus can live on copper for up to four hours, cardboard for about one day and plastic and stainless steel for about two to three days, according to an April letter to the editor published in The New England Journal of Medicine.
A separate paper from Japan showed that SARS-CoV-2 can remain infectious on human skin for up to nine hours, while the influenza A virus survived for just under two hours on skin.
The researchers note that so far, the primary way the coronavirus spreads appears to be through the air in tiny respiratory droplets, and less so through contaminated surfaces, also known as fomite transmission.
But surfaces slathered with pathogens are known to have been an important factor in spreading past viruses such as the Middle East Respiratory Syndrome and human coronaviruses 229E and OC43, which cause the common cold.
To test what risks exist for fomite transmission for SARS-CoV-2, the researchers mixed samples of the coronavirus with artificial mucus, and placed the cocktail on paper and plastic money, stainless steel, glass, cotton and vinyl, a type of plastic.
The contaminated surfaces were then placed in sterilized petri dishes under different temperatures: 68 degrees, 86 degrees and 104 degrees Fahrenheit. The dishes were set in a dark room to test how long the virus survives without the effect of ultraviolet light, which has been shown to deactivate virus particles.
At 68 degrees, or about room temperature, the virus was “extremely robust,” surviving for 28 days on the smooth, non-porous surfaces tested, according to the study. The higher the temperature, the less time SARS-CoV-2 remained infectious.
This might explain “the apparent persistence and spread” of the virus in cool environments such as meat processing plants, Trevor Drew, study co-author and director of the ACDP, said in the news release.
The coronavirus lasted for the least amount of time on cotton — seven days — which often makes up clothing, bedding and other household fabrics.
At 86 degrees, the coronavirus was “recoverable” for seven days on stainless steel, plastic money and glass, and three days on vinyl and cotton. Meanwhile, the virus was undetectable on all smooth surfaces in just two days and on cotton after 24 hours in this temperature setting.
Although the study took place in a controlled laboratory in artificial mucus with zero exposure to UV light, “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,” Dr. Larry Marshall, CSIRO chief executive, said in the release.
In addition, a virus’s survivability and infectiousness depends on several factors including the type of virus it is, its quantity, the surface it’s on, how it’s deposited and the environmental conditions it’s in, experts say.