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The new coronavirus can remain infectious for weeks on banknotes, glass and other common surfaces, according to research by Australia’s leading biosafety laboratory that highlights the risks of paper money, touchscreen devices and handles and rails.
Scientists from the Australian Center for Disease Preparedness have shown that SARS-CoV-2 is “extremely robust”, surviving for 28 days on smooth surfaces such as glass found on mobile phone screens and plastic banknotes. at room temperature, or 20 degrees Celsius (68 degrees Fahrenheit). That compares with the 17-day survival for the flu virus.
Survival of the virus was reduced to less than a day at 40 degrees Celsius on some surfaces, according to the study, published in the Virology Journal. The findings add to evidence that the coronavirus that causes Covid-19 survives longer in colder climates, making it potentially more difficult to control in winter than in summer. The research also helps more accurately predict and mitigate the spread of the pandemic, the scientists said.
“Our results show that SARS-CoV-2 can remain infectious on surfaces for long periods of time, reinforcing the need for good practices such as regular hand washing and surface cleaning,” said co-author Debbie Eagles, deputy director. from the center, in an emailed statement Monday.
The coronavirus is mainly transmitted through direct contact with an infected person, especially the virus-laden particles that they emit when coughing, sneezing, talking, singing and even breathing. SARS-CoV-2 can also contaminate surfaces when these particles settle, creating so-called fomites that researchers say may play a minor, but important, role in virus transmission.
“It does raise some critical issues around the need to keep disinfecting surfaces, even when community cases are low,” Trevor Drew, director of the center and another co-author, said in an interview. “We still have to carry out those disinfection regimes, both personally and publicly, even when there appears to be no case, because there may well be some residual virus that has been lost.
The spread of SARS-CoV-2 through fomites is plausible, researchers at Kansas State University said in a study published ahead of publication and peer review in August. They analyzed the stability of the coronavirus on a dozen surfaces and found that it survived five to seven times longer in cooler and less humid spring / fall conditions compared to the average temperature and humidity in summer.
‘Big surprise’
The finding bodes ill for Covid-19 control during the northern hemisphere winter, said virologist Juergen Richt, who led the research. “If we couldn’t control it very well during the summer, we’re in for a big surprise,” Richt said in an interview.
Scientists in the Australian government laboratory have previously determined virus survival for hundreds of different viruses. In the case of SARS-CoV-2, they found that it survives longer on smooth or non-porous surfaces, compared to complex porous surfaces, such as cotton.
The research received funding from the Australian Department of Defense. It involved drying the coronavirus in an artificial mucus on different surfaces, at concentrations similar to those reported in samples from infected patients, and then re-isolating the virus for a month. The study was also carried out in the dark to eliminate the effect of ultraviolet light, as research has shown that direct sunlight can quickly inactivate the virus.
“While the precise role of surface transmission, the degree of surface contact, and the amount of virus required for infection have yet to be determined, establishing how long this virus remains viable on surfaces is critical to developing risk mitigation strategies. in high contact areas “. Eagles said.
Transmission risk
Persistence in glass is an important finding, as touch screen devices such as mobile phones, bank ATMs, supermarket checkouts, and airport check-in kiosks are high-touch surfaces that may not be cleaned regularly and, therefore, they represent a risk of SARS transmission. -CoV-2, the researchers said in the article.
They found that the longer survival time of SARS-CoV-2 than seasonal flu on banknotes is “of particular importance, considering the frequency of circulation and the potential for transfer of viable viruses both between individuals and between geographic locations.”
Before SARS-CoV-2 was declared a pandemic, China had begun decontaminating its paper money, suggesting that there were concerns about transmission via paper notes at the time, the researchers said, noting that the United States and South Korea have also quarantined banknotes as a result. of the pandemic.
Survival of the coronavirus in stainless steel at colder temperatures may help explain the Covid-19 outbreaks related to meat processing and cold storage facilities, the authors said. Their data supports the findings of a study showing the survival of SARS-CoV-2 also in fresh and frozen foods, they said.
A reduction in temperature to about 6 degrees Celsius correlates with a roughly 10-fold increase in virus survival, Drew said. The blood and oils associated with the processing and handling of fresh meat and fish can also help preserve the virus.
“It will survive much longer in colder conditions, regardless of whether it is on a surface or in the air,” said Drew. “This may help explain why the type of environments, such as slaughterhouses, would potentially be a more dangerous area.”
