The virus responsible for Covid-19 can remain infectious on surfaces such as banknotes, phone screens and stainless steel for 28 days, researchers say. The findings from Australia's national science agency suggest SARS-Cov-2 can survive for far longer than thought. However, the experiment was conducted in the dark. UV light has already been shown to kill the virus. Some experts have also thrown doubt on the actual threat posed by surface transmission in real life. The coronavirus is mostly transmitted when people cough, sneeze or talk. But there is also evidence that it can also be spread by particles hanging in the air. It is also possible someone could get Covid-19 by touching infected surfaces such as metal or plastic, according to the US Centers for Disease Control. This is believed to be much less common, however.
Previous laboratory tests have found that SARS-Cov-2 can survive for two to three days on bank notes and glass, and up to six days on plastic and stainless steel, although results vary. However, the research from Australian agency CSIRO found the virus was "extremely robust," surviving for 28 days on smooth surfaces such as glass found on mobile phone screens and both plastic and paper banknotes, when kept at 20C (68F), which is about room temperature, and in the dark. In comparison, the flu virus can survive in the same circumstances for 17 days. The study, published in Virology Journal, also found SARS-Cov-2 survived for less time at hotter temperatures than cooler temperatures; it stopped being infectious within 24 hours at 40C on some surfaces. It also stayed longer on smooth, non-porous surfaces than on porous materials such as cloth, which was found not to carry any infectious virus past 14 days.