The findings of Australian researchers on SARS-CoV-2 reinforce the need for effective hand washing and cleaning.
Australian researchers said Monday that the virus that causes COVID-19 can survive on banknotes, glass and stainless steel for up to 28 days, much longer than the flu virus, highlighting the need for effective cleaning and hand washing to help fight the disease.
The results of the study by the Australian National Science Agency, CSIRO, seem to show that in a tightly controlled environment, the virus has been contagious for longer than other studies have found.
At 20 ° C (68 ° F) the SARS-COV-2 virus was “extremely powerful” and remained infectious for 28 days on smooth surfaces such as plastic and glass banknotes found on mobile phone screens, CSIRO researchers said. The study has been published in Virology Journal.
By comparison, influenza A virus was found to survive on surfaces for 17 days.
“It really reinforces the importance of hand washing and sanitizing where possible, and definitely wiping surfaces that may have been in contact with the virus,” said lead researcher Shane Riedl.
Experiments at temperatures of 20, 30, and 40 degrees Celsius (68, 86 and 104 Fahrenheit) showed that the virus survived longer in cooler temperatures, smooth surfaces, and on paper notes rather than plastic ones.
The researchers said that on canvas at a temperature of 20 ° C, they were unable to detect any viable virus after 14 days. At 30 degrees, the viability of the virus was reduced to only three days on cotton, compared to seven days for steel and smoother surfaces. The viability decreased the most at 40 ° C (104 ° F).
All experiments were conducted in the dark to remove the effect of ultraviolet rays, as research has shown that direct sunlight can kill the virus.
“So the results in the real world are likely to be shorter than we have been able to show,” Riddle told Reuters news agency.
The results are helpful but should be taken into account, said Julie Liske, a professor at Susan Keil School of Nursing and Midwifery at the University of Sydney’s School of Medicine and Health.
Leask wrote on Twitter: “The study advantageously confirms that surfaces may be a means of transmitting the Corona virus, but we must look into epidemiology for how it actually transmits between people in everyday life.” “This data shows that close contact with an infected person is still dangerous and not from touching his mobile phone after 5 days.”
The infectious dose of SARS-CoV-2 is not yet known, but it is believed, based on the related viruses, to consist of about 300 particles. The researchers said that if the virus was placed on smooth surfaces with a standard mucus concentration of an infected person, “a sufficient number of viruses can easily live for two weeks to be able to infect another person.”
CSIRO indicated that the infection will depend on a number of factors, including the composition of the virus itself, the type of surface, and whether the virus is liquid or dry.
She added that the study may also help explain the persistence and spread of the virus in cold environments such as meat packing facilities.