Researchers from Australia’s national scientific agency, CSIRO, have found that the COVID-19 coronavirus can survive on certain surfaces, such as banknotes and phone screens, for up to 28 days – roughly seven times longer than previous experiments suggested.
“These findings demonstrate that SARS-CoV-2 can remain infectious for significantly longer periods of time than is generally considered possible. These results could be used to inform improved risk mitigation procedures to prevent the spread of COVID-19 by fomites, ”the researchers wrote in their conclusion, published last week in Virology Journal.
The experiment, which measures the time it took for virus samples to become inactivated when left on different surfaces, was carried out at three ambient temperatures: 20 ° C, 30 ° C and 40 ° C. The virus survived longer on surfaces smooth, like glass and plastic.
In the case of glass and polymer banknotes, smooth and wax-like banknotes used in Australia and other countries, 90% of the virus sample took 6 days to inactivate at 20 ° C. The paper money was even more hospitable , with 90% of the virus sample expiring after 9.13 days at 20 ° C.
Establishing how long this virus remains viable on surfaces is critical to developing risk mitigation strategies in high touch areas.
China began treating its banknotes in February, in an attempt to stop the transmission of the currency. The banks were ordered to sterilize the notes with heat or ultraviolet light and then store the notes for 14 days before putting the money into circulation. The country is also perhaps the best prepared to forego cash, as roughly 60% of the world’s mobile payment users are in China.
CSIRO’s research also found that the virus survived longer at a lower temperature. Observational evidence already suggested that this was the case. New Zealand investigated the possibility that frozen food imports also brought COVID-19 into the country.
But even though the virus can survive on surfaces for longer than previously thought, the surfaces themselves pose a relatively low risk of transmission. The virus can only infect a person if it enters their body, usually through the mouth. In normal situations, where surfaces are exposed to the elements, the virus may not survive as long.
What the research reaffirms, Eagles says, is the importance of adopting best practices when it comes to personal hygiene, such as washing hands at regular intervals and cleaning surfaces.
