The virus responsible for COVID-19 can survive for up to 28 days on surfaces including bank notes, phone screens and stainless steel, according to a study by Australian researchers.
The study by Australia’s national science agency, the Commonwealth Scientific and Industrial Research Organization (CSIRO), showed that, in controlled conditions, the SARS-CoV-2 coronavirus tended to survive longer at lower temperatures on nonporous or smooth surfaces such as glass, stainless steel and vinyl, compared with porous complex surfaces such as cotton.
“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 found on mobile phone screens and plastic bank notes,” said Dr. Debbie Eagles, deputy director of Director of Australian Centre for Disease Preparedness, which led the research.
By comparison, Influenza A has been found to survive on surfaces for 17 days.
“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,” Eagles added.
She said the results of the study reinforce the need for good practices such as regular handwashing and cleaning surfaces.
The peer-reviewed study, published on Oct. 7 in Virology Journal, involved drying the 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.
Experiments carried out at 20 °C, 30 °C and 40 °C, showed that the virus survived longer at cooler temperatures and on smooth surfaces than on complex surfaces such as cotton. The infectious virus survived less than 24 hours at 40 °C on some surfaces, the study found.
All the experiments were carried out in the dark, to remove the effects of ultraviolet light, as research has demonstrated direct sunlight can rapidly inactivate the virus.
The CSIRO researchers said that as proteins and fats in body fluids can also significantly increase virus survival times, their research may help explain the apparent persistence and spread of the virus in cool environments with high lipid or protein contamination, such as meat processing facilities.
An earlier study published in April in The Lancet found no infectious virus could be detected on glass or bank notes after four days, or after seven days for stainless steel.
“Respiratory droplets can also land on surfaces and objects. It is possible that a person could get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or eyes. Spread from touching surfaces is not thought to be a common way that COVID-19 spreads,” it says on its website.