Australian scientists have discovered that the virus causing Covid-19 can survive for up to 28 days on surfaces such as glass, stainless steel, vinyl, and paper banknotes. The research, conducted by the national science agency CSIRO at the Australian Centre for Disease Preparedness (ACDP) in Geelong, found that the virus survives longer at lower temperatures and lasts 10 days longer than influenza on some surfaces.
The study, published in the Virology Journal, showed that Sars-CoV-2 survived longer on paper banknotes than on plastic, and on smooth surfaces compared to porous ones like cotton. However, the experiments were conducted in darkness, eliminating the effects of UV light, which is known to reduce virus survival. Professor Peter Collignon of the Australian National University noted that UV light inactivates the virus, making outdoor environments safer.
Despite the findings, experts caution that surface transmission may account for only a small fraction of infections. Professor Collignon estimates that 90% of transmission occurs through close contact with infected individuals via droplets, with only about 10% attributed to hands and surfaces. He emphasised the importance of hand washing before touching one's face.
CSIRO chief executive Dr Larry Marshall stated that understanding virus survival on surfaces helps predict and prevent spread. At 20°C, the virus remained robust for 28 days on smooth surfaces like mobile phone screens, while Influenza A survived for 17 days under similar conditions. Survival times decreased at higher temperatures of 30°C and 40°C.
Dr Debbie Eagles, deputy director of ACDP, reinforced the need for regular hand washing and surface cleaning. Professor Trevor Drew, ACDP director, suggested the research may explain virus persistence in cool environments like meat processing facilities, aiding in developing risk-mitigation strategies.
