The screen of your smartphone is an almost ideal surface for the coronavirus. Researchers at Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) have found that the Covid-19 virus can remain infectious on surfaces such as banknotes and smartphone screens for much longer than previously thought – up to 28 days. However, some experts have questioned whether viruses that persist on surfaces pose a real risk of infection. More commonly, the coronavirus is spread through airborne droplets from sneezing, coughing or talking.
At the same time, Australian scientists were conducting experiments in the dark, even though ultraviolet light is known to kill viruses. Previous laboratory studies have shown that SARS-Cov-2 can persist on banknotes and glass surfaces for up to two to three days and on plastic and steel for up to six days. But now scientists at CSIRO have discovered that the coronavirus is much more resilient and can survive on smooth surfaces such as plastic and paper banknotes and smartphone glass screens for up to four weeks at room temperature. By comparison, the common flu virus can survive in the same conditions for up to 17 days.
“By understanding how long the virus actually remains viable on surfaces, we can better predict and contain its spread and better protect the community,” said Dr. Larry Marshall, Executive Director of CSIRO. However, the former director of the Common Cold Centre at Cardiff University, Professor Ron Eccles, criticized the Australians’ work, saying that the assumption that the virus can live on surfaces for 28 days “instills unwarranted fear in people”. “Viruses get onto surfaces from dirty fingers and droplets of mucus from coughing and sneezing, and this study did not consider fresh mucus as a mechanism of virus transmission,” explains Professor Eccles. “Meanwhile, such fresh mucus serves as a hostile environment for viruses because it contains numerous white blood cells that produce enzymes that destroy viruses, and it may also contain antibodies and other elements that neutralize these viruses. Therefore, in my opinion, infectious viruses present in mucus on surfaces can survive for a few hours at most, but definitely not for days. And Professor Monica Gandhi of the California University of Medicine told Nautilus magazine last week that the coronavirus is not transmitted through surfaces. “At the beginning of the pandemic, many people were concerned about secondary transmission, but now we know that the reason it spreads is not because you touch surfaces and your eyes, but because you are close to carriers of the virus, from whom it is released through the nose and mouth, although they are often unaware of it,” Professor Gandhi explained. Covid-19 spreads primarily through respiratory droplets. Scientists have determined that infection can occur in this manner for more than three hours after the virus enters the air. However, much less was known about the ability of viruses to remain infectious on surfaces.
We explain quickly, simply, and clearly what happened, why it matters, and what happens next. The number of offers should remain: episodes. End of story Podcast advertising In particular, the assessment of virus survival on steel surfaces yielded a very wide range of results: from 3 to 14 days at room temperature. The authors of the new study wanted to find out how long the virus remained viable on glass, paper and plastic banknotes, and steel. They found that it survives much longer at room temperature than previously thought. The experiments were conducted under conditions favorable to the survival of the virus – in darkness and at constant humidity and temperature, which are practically nonexistent in real life. But when the temperature was raised to 40 degrees, the viruses did not survive for even a day. In addition, the viruses felt more comfortable on a smooth surface, and there was no trace of them on fabrics, for example, after 14 days. However, experts point out that the golden rule of washing hands regularly has not been eliminated, but the need to clean smartphone screens more often has been added. Scientists have also linked SARS-Cov-2’s tendency to survive better on steel surfaces at low temperatures to outbreaks of Covid-19 in meatpacking plants and cold storage facilities around the world. The CSIRO researchers also emphasize that, based on their experiments, it can be concluded that viruses are able to survive on fresh and frozen foods.