The virus that causes COVID-19 can stay active on smooth surfaces like smartphones, metal surfaces, and paper money for much longer than the flu virus, according to researchers from Australia’s national science agency.
They found that it can remain viable for up to 28 days, albeit in a very controlled environment. Under the same conditions, the influenza virus remains infectious for just 17 days, according to the study.
The team said the research proves that the coronavirus is “extremely robust” compared to other viruses. “These findings demonstrate SARS-CoV-2 can remain infectious for significantly longer time periods than generally considered possible,” the study concludes. (Cloth and other porous surfaces can carry infectious virus for just half the time, or around 14 days.)
While it shows the importance of cleaning and disinfecting smartphones and other surfaces, the study comes with some large caveats. It was conducted at a constant 68 degrees F temperature in dark conditions to negate the effects of UV light, far from real-world conditions.
The experiment also didn’t use fresh mucous — normally present with viruses on surfaces — which contain white cells and antibodies. “In my opinion infectious viruses will only persist for hours in mucus on surfaces rather than days,” Cardiff University professor Ron Eccles told the BBC.
Recently, experts have also downplayed the risk of coronavirus transmission from surfaces. According to the center for disease control (CDC), “spread from touching surfaces is not thought to be a common way that COVID-19 spreads.”
Rather, the most common vectors are respiratory droplets produced by coughing or sneezing. New guidelines also suggest that it can also be transmitted by airborne transmission in “poorly ventilated and enclosed spaces that often involved activities that caused heavier breathing, like singing or exercise.”