On surfaces such as banknotes, phone screens and stainless steel, the virus responsible for COVID-19 may remain infectious for 28 days, researchers from Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) say.
SARS-Cov-2 can live for much longer than expected, the findings of Australia’s national science agency indicate. However, the experiment was conducted in the dark and confirmed that it can be destroyed with UV light, which was established by earlier studies too.
Previous laboratory studies have shown that on bank notes and glass, SARS-Cov-2 can live for two to three days and on plastic and stainless steel for up to six days, although results differ.
But now the Australian CSIRO research found that the virus was “highly stable,” surviving for 28 days on smooth surfaces such as glass found on mobile phone screens and both plastic and paper banknotes, when kept at room temperature 20C (68F) and in the dark. In contrast, the flu virus can live for only 17 days in the same circumstances.
SARS-Cov-2 also survived for less time at hotter temperatures than cooler temperatures in the study and on certain surfaces, it stopped being infectious within 24 hours at 40C temperature. It also remained longer on smooth, non-porous surfaces than on porous materials such as cloth, which after 14 days was not found to contain any infectious virus.
However, the experiments were carried out under virus-friendly conditions which includes a dark room with stable temperatures and humidity, so the virus in the real world may not do so well.
But some experts have cast doubts on the actual threat posed in real life by surface transmission. Coronavirus is usually transmitted when individuals cough, sneeze or speak.
But there is proof that particles hanging in the air can also be transmitted. According to the US Centers for Disease Control (CDC), it is possible that someone might get COVID-19 by touching contaminated surfaces like metal or plastic. However, this is assumed to be much less common.
Few experts criticized the latest study and said “unnecessary public fear” was being caused by the suggestion that the virus could survive for 28 days.
Microbiologists had earlier said that “the probability of transmission through inanimate surfaces is very small.” They said that the experiments were designed with “no relation to real-life scenarios” and could not be relied on much.
Monica Gandhi, a professor of medicine at a US university, said last week that the coronavirus did not spread through surfaces.
Continue precautionary measures
But even these findings demonstrate the need to frequently wash hands and touchscreens and to avoid touching one’s face in order to reduce the risk of infection.
“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,” says the news study.
The authors of the study said SARS-Cov-2’s ability to survive on stainless steel at cooler temperatures could explain COVID-19 outbreaks at meat processing and cold storage facilities.
At meat processing factories around the world, thousands of employees have tested positive. Close working conditions, cold and humid weather and the need to shout over loud machines are other factors previously suggested as the cause for this spread.
The CSIRO researchers also say their results support previous research that shows that the virus can survive on fresh and frozen food.
But the World Health Organization (WHO) says that, “There is currently no confirmed case of COVID-19 transmitted through food or food packaging.”