The study also found that the virus survived longer at lower temperatures and tended to last longer on non-porous or smooth surfaces such as glass and stainless steel rather than porous or rough surfaces such as cotton.
“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,” Larry Marshall, the CEO of Australia’s national science agency CSIRO, said in a statement.
Around a room temperature of 68 degrees Fahrenheit, the coronavirus could last for 28 days on smooth surfaces. At higher temperatures, the survival time decreased as the temperature increased, and on cotton, the virus wasn’t detectable after 14 days.
However, the study was conducted in the dark to remove the effect of UV light, which can inactivate the virus. That means the lab conditions may not match the real world. The items were left undisturbed as well, but phone screens and banknotes are often moved around, which could wipe off the virus.
“What we’re seeing empirically, clinically, with contact tracing, is that COVID is not spreading heavily through touch,” Colin Furness, an infection control epidemiologist at the University of Toronto, told CTV News.
“It is possible to contract the virus through surfaces,” he said. “But it’s not happening very often.”
In addition, the study tested how long the virus lasts on surfaces but not how long the virus particles are actually infectious. Influenza A, for instance, has been found to survive on surfaces for 17 days, but a virus begins to degrade once it leaves a host’s body.
“How long [a virus] can survive and remain infectious depends on the type of virus, quantity, the surface, environmental conditions and how it’s deposited — for example, touch versus droplets emitted by coughing,” Trevor Drew, director of the Australian Centre for Disease Preparedness, said in the statement.