According to a study by the Australian National Science Agency he coronavirus can survive up to 28 days on surfaces, like banknotes or telephones, in cold temperatures and in the dark. Researchers at the Center for Disease Prevention Commonwealth Industrial and Scientific Research Organization (CSIRO, for its acronym in English) tested the longevity of the virus in three types of temperatures.
Survival rates decrease when temperatures are higher and they found that, at a temperature of 20ºC, covid is “extremely resistant” on smooth surfaces such as mobile phone screens, surviving up to 28 days in glass, steel or banknotes . At 30ºC, survival falls to 7 days and 24 hours at temperatures of 40ºC. 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 longer than the results of previous studies carried out by the specialized journal ‘Virology Journal’, where it was stated that the virus could survive up to four days on smooth surfaces.
The virus stays on surfaces
The director of Australian Center for Disease Prevention, Trevor Drew has explained that the study was carried out with virus samples on different materials before subjecting them to an “ultrasensitive” method. Remains of the virus capable of infecting cultured cells were found. “This does not mean that people can become infected,” he said on ABC public television, but if a person is not “careful with these materials, touches them and then puts his hands to his mouth, eyes or nose, he could become infected up to two weeks after those objects have been contaminated.
The study was carried out with levels of the virus that represent the peak of the infection, but it was not exposed to ultraviolet lights, which usually destroy the virus, and the humidity of the environment was kept at 50%, so as not to damage the samples.
People are more infectious
According to CSIRO, the virus is spread primarily through the air but more research is needed to establish its transmission 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 contact and the amount of virus it takes to become infected and to establish how long it remains viable,” says Debbie Eagles by CSIRO.
Trevor Drew’s main message is that people are much more infectious than surfaces. “However, it may help to explain why, when even no people are infected, there are sometimes new outbreaks, even in countries that are considered virus-free.”