Coronavirus may stay for weeks on banknotes, touchscreens: Study

*SARS-CoV-2 has been found to persist longer on smooth surfaces, as researchers reinforce the need for regular hand-washing and cleaning

Alexander Davis | ConsumerConnect

A fresh study has revealed that the novel Coronavirus (COVID-19) may remain infectious for weeks on banknotes, glass, and other common surfaces.

Australia’s top biosecurity laboratory, in a research, highlights that there are risks of infections from paper currency, touchscreen devices and grab handles and rails, says agency report.

Scientists at the Australian Centre for Disease Preparedness, in the study published in Virology Journal, showed SARS-CoV-2 is “extremely robust,” thereby 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 17 days survival for the flu virus, it was learnt.

Virus survival declined to less than a day at 40 degrees Celsius on some surfaces.

The latest study was said to have reinforced evidence that the COVID-19-causing Coronavirus survives for longer in cooler weather, making it potentially harder to control in winter than summer.

The new research also helps to more accurately predict and mitigate spread of the ravaging pandemic, according to the scientists.

Debbie Eagles, Deputy Director of the Australian Centre for Disease Preparedness, in an e-mail communication, 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 cleaning surfaces.”

Disease experts opine that the Coronavirus is transmitted mostly through direct contact with an infected person, especially the virus-laden particles they emit while coughing, sneezing, speaking, singing and even breathing.

“SARS-CoV-2 may also contaminate surfaces when these particles settle, creating so-called fomites that the researchers said ‘may also be an important contributor in transmission of the virus.’ ”

According to scientists, though not proven, SARS-CoV-2 spread via fomites is plausible as researchers at the Kansas State University, in the US, said in a study released ahead of publication and peer review in August 2020.

The researchers analysed the Coronavirus’s stability on a dozen surfaces and found it survived five-to-seven times long under cooler, less-humid spring/fall conditions compared with the average temperature and humidity in summer.

Virologist Juergen Richt, who led the research stated that the finding bodes badly for controlling COVID-19 during the Northern Hemisphere winter.

In what is described as ‘Big Surprise’, Richt in an interview said: “If we couldn’t control it very well during the summer, we are in for a big surprise.”

The scientist at the Australian Government laboratory found the coronavirus tended to survive longer on nonporous or smooth surfaces, compared with porous complex surfaces, such as cotton.

The research, which attracted funding from Australia’s defence department, involved drying the Coronavirus in 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. The study was also carried out in the dark, to remove the effect of ultraviolet light, as research has demonstrated direct sunlight can rapidly inactivate the virus.

The time taken to achieve a 90% reduction in the amount of virus present on the surfaces studied under different temperatures is tabled below:

                                            20 DEGREES CELSIUS      30 DEGREES CELSIUS             40 DEGREES CELSIUS

Stainless steel                      5.96 days                              1.74 days                                    4.86 hours

Polymer note                        6.85 days                              2.04 days                                    4.78 hours

Paper note                           9.13 days                              4.32 days                                     5.39 hours

Glass                                   6.32 days                               1.45 days                                    6.55 hours

Cotton                                  5.57 days                              1.65 days                                    none recovered

Vinyl                                    6.34 days                               1.4 days                                      9.9 hours

Eagles stressed “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.”

In terms of the transmission risk, the study found that the persistence on glass is an important finding, given that touchscreen devices such as mobile phones, bank ATMs, supermarket self-serve checkouts and airport check-in kiosks are high touch surfaces.

The researchers in the paper said that such surfaces may not be regularly cleaned, and therefore, pose a transmission risk of SARS-CoV-2.

They found the longer survival time of SARS-CoV-2 than seasonal flu on banknotes “of particular significance, considering the frequency of circulation and the potential for transfer of viable virus both between individuals and geographic locations.”

According to the researchers, prior to the time SARS-CoV-2 was declared a pandemic, China had started decontaminating its paper currency, suggesting concerns over transmission via paper banknotes existed at the time.

They noted that the US and South Korea have also quarantined bank notes as a result of the pandemic.

The survival of the Coronavirus on stainless steel at cooler temperatures may help explain COVID-19 outbreaks linked to meat processing and cold storage facilities, the authors said.

Their data support the findings of a study showing the survival of SARS-CoV-2 on fresh and frozen food as well, they said.

Trevor Drew, Director of Australian Centre for Disease Preparedness, in the statement disclosed that “the research may also help to explain the apparent persistence and spread of SARS-CoV-2 in cool environments with high lipid or protein contamination, such as meat processing facilities and how we might better address that risk.”

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