The coronavirus that causes covid-19 can survive on surfaces such as bank notes or telephones for up to 28 days in low temperatures and in the dark, according to a study by the Australian National Science Agency.
Researchers from the CSIRO Center for Disease Prevention tested the longevity of SARS-CoV-2 in the dark under three types of temperatures. Survival rates decline when temperatures are hotter, the agency announced Monday.
The scientists found that at a temperature of 20ºC, SARS-CoV-2 is “extremely resistant” on smooth surfaces such as mobile phone screens, surviving up to 28 days on glass, steel or plasticized banknotes.
At 30º, survival falls to 7 days and 24 hours in temperatures of 40º.
The virus survived shorter periods on porous surfaces like cotton “up to 14 days at low temperatures and less than 16 hours at high,” according to the researchers.
This is “significantly longer” than the results of previous studies that found that the virus can survive up to four days on smooth surfaces, according to the report published in the journal Virology Journal.
Trevor Drew, director of the Australian Center for Disease Prevention, said the study was conducted with samples of the virus in different materials before subjecting them to an “ultrasensitive” method that found traces of live virus capable of infecting cultured cells.
“This does not mean that the amount of virus could infect someone,” he said on ABC public television.
If a person is not “careful with these materials and touches them and then puts their hands in their mouth or touches their eyes or nose, they could become infected up to two weeks after (those objects) were contaminated,” he warned.
– People “are much more infectious” –
Drew said there are some reservations. Among them, that the study was conducted with fixed levels of virus that could represent the peak of a typical infection, and there was no exposure to ultraviolet light, which can rapidly destroy the virus.
The humidity was kept constant at 50% although the increase in humidity also harms the virus, the study says.
According to CSIRO, the virus is spread primarily through the air but more research is needed to establish transmission of the virus through surfaces.
“To develop risk mitigation strategies in high contact areas it is essential to determine the precise role of surface transmission, the degree of surface contact and the amount of virus it takes to become infected and how long (the virus) it remains viable, “says CSIRO’s Debbie Eagles.
But the main message is that “people are by far more infectious than surfaces,” Drew told ABC.
“However, it may help to explain why even when people are not infected, there are sometimes new outbreaks, even in countries that are considered free” of the virus, he said.
hr / arb / qan / af / lp