Coronavirus may survive on glass, banknotes for 28 days: Study
The novel coronavirus may last up to 28 days on glass screens or banknotes, a recent study by Australia's top biosecurity laboratory has found. The study assumes significance as glass covers several commonly touched surfaces such as mobile phones, ATMs, airport check-in kiosks, etc. Although surface or fomite transmission is not yet proven, the study underlines the potential for transmission through touchscreens and banknotes.
Study involved drying coronavirus in artificial mucus on different surfaces
The study was conducted by researchers at the Australian Centre for Disease Preparedness (ACDP) and received funding from Australia's defense department. It involved drying the coronavirus in an artificial mucus on different surfaces—such as stainless steel, paper note, polymer note, glass, etc.—to analyze the survivability of the virus on those surfaces under specific conditions. The virus was then re-isolated over a month later.
Study also conducted in dark, to remove UV as factor
Notably, the researchers used viral concentrations similar to those reported in samples from infected patients. Further, the study was also conducted in the dark, to eliminate ultraviolet light as a factor as it has been demonstrated to rapidly inactivate the virus.
Virus survives longer on smoother surfaces
The study—published in Virology Journal—found that the virus can survive longer on nonporous or smooth surfaces, compared with porous complex surfaces, such as cotton. Thus, the virus may remain viable longer on smooth surfaces such as glass or plastic. "The persistence of both SARS and SARS-CoV-2 on cotton has been demonstrated to be significantly shorter than on non-porous surfaces," the study noted.
Virus may survive up to 28 days on some surfaces
The virus may survive up to 28 days at room temperature (20°C) on glass, stainless steel, and paper/polymer banknotes. At 40°C, the virus's survival dropped to less than a day on some surfaces. The persistence on glass is an important finding, given that touchscreen devices such as mobile phones, bank ATMs, airport check-in kiosks are high touch surfaces, the researchers noted.
Coronavirus survives on currency longer than flu virus
In comparison, the flu virus can survive 17 days on currency at room temperature. The researchers said that this is "of particular significance, considering the frequency of circulation and the potential for transfer of viable virus both between individuals and geographic locations."
'Findings important for developing risk mitigation strategies'
Debbie Eagles, ACDP's Deputy Director, said in an emailed statement to Bloomberg, "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."
Study may explain infections in meat processing facilities: ACDP Director
ACDP Director Trevor Drew added, "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."
Studies indicate greater risk of viral spread in winter
The findings also indicate that the virus poses a greater risk in the winter compared to the summer. Although fomite transmission is not proven, a similar study conducted by researchers at Kansas State University—released ahead of publication and peer review in August—found that the virus can survive five-to-seven times longer under cooler, less humid conditions, compared to average temperature and humidity in the summer.
'We're in for a big surprise in winter'
Juergen Richt, who led the Kansas study, told Bloomberg in an interview that the finding bodes badly for controlling COVID-19 during the Northern Hemisphere. Richt said, "If we couldn't control it very well during the summer, we are in for a big surprise."
