Coronavirus May Stay On Surfaces Longer Than Expected, Scientists Say

Transmission of the coronavirus is believed to occur predominantly through prolonged and close person-to-person contact. That is why masking, maintaining social distancing and hand washing are essential to prevent infection. But from the early days of the pandemic Scientists have also tried to understand how SARS-CoV-2, the virus that causes COVID-19, can survive and spread through contaminated surfaces.

New research by scientists at CSIRO, Australia’s national scientific agency, suggests that SARS-CoV-2 may remain on non-porous surfaces for longer than expected. The study, published in Virology Journal on Monday, was conducted in controlled laboratory conditions and in the dark, but reveals the resistance of SARS-CoV-2 when conditions are single law.

“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 Debbie Eagles, deputy director of the Australian Center for Disease Preparedness. (ACDP).

The team isolated the virus and created a solution described as “artificial mucus” that contains viral particles in a concentration similar to those seen in infected patients. They placed drops of the mixture on a variety of different surfaces, including plastic and paper banknotes, stainless steel, cotton, and vinyl. They also tested glass, such as that used in ATMs, boxes and mobile phones.

The team’s goal was to find out if the virus was still infectious on surfaces after it had been exposed to temperatures of 20, 30 and 40 degrees Celsius (68, 86 and 104 degrees Fahrenheit). They sampled the materials at five different time points, ranging from one hour to 28 days.

Their results showed that the virus can remain viable for at least 28 days at 20 degrees Celsius, similar to the figures reported for the original SARS virus, but longer than previously published data on SARS-CoV-2. An important finding, the researchers write, is persistence in glass and the ability to detect SARS-CoV-2 from something like a smartphone screen.

However, the team notes that the study was conducted under controlled conditions, which may improve the survival time of the virus. The increase in temperature decreased the virus’s ability to survive. At 40 degrees Celsius, SARS-CoV-2 was no longer viable within 48 hours. In the opposite direction, at even colder temperatures, the virus may have an even greater chance of survival.

“The research may also help explain the apparent persistence and spread of SARS-CoV-2 in cold environments with high lipid or protein contamination, such as meat processing facilities,” explained Trevor Drew, director of ACDP, who conducted the studies. Australia has seen several cases of COVID-19 outbreaks at meat packing facilities.

The study adds to a growing body of evidence on the resistance of SARS-CoV-2 to the elements, but it does not resolve the debate of transmission through infected surfaces.

“While the precise role of surface transmission, the degree of surface contact and the amount of virus required for infection, has not yet been determined,” Eagles noted. “Establishing how long this virus remains viable on surfaces is essential to develop risk mitigation strategies in high-contact areas.”

The argument in favor of “fomite transmission” (infection through contaminated surfaces) has appeared numerous times during the course of the pandemic, since March. Several studies have shown that the coronavirus can persist on a variety of surfaces, but it is unclear how relevant this is outside the laboratory. In July, a commentary published in the prestigious medical journal The Lancet suggested that the risk of transmission through fomites was “exaggerated” because the studies are mainly done in the laboratory, which does not accurately replicate real-world scenarios.

CDC Notes “COVID-19 spreads less frequently through contact with contaminated surfaces” and reiterates that the main mechanisms of infection are through droplets and aerosols from infected people.

While there may be more impetus for cleaning your smartphone screen with disinfectant, the top health tip for most of the public remains unchanged: mask yourself, socially distance yourself, and wash your hands.

Update Oct 11: Title changed to reflect quotes, clarified the Eagles quote.