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The coronavirus that causes COVID-19, SARS-CoV-2, can survive for several hours in an aerosolized form and for up to three days on plastic and steel surfaces, researchers reported Tuesday (March 10) on medRxiv. While the detection of viable virus means it’s theoretically possible to transmit the disease from contaminated surfaces or from the air—in addition to the typical route of having larger droplets land directly on a new host after an infected person, say, coughs in their proximity—“We’re not by any way saying there is aerosolized transmission of the virus,” coauthor Neeltje van Doremalen of the National Institute of Allergy and Infectious Diseases tells the Associated Press.

The authors applied SARS-CoV-2 and SARS-CoV, the virus that caused the SARS outbreak of 2003, to plastic, stainless steel, copper, and cardboard in the lab and created aerosolized viruses using a nebulizer.

They found viable SARS-CoV-2 three hours after the virus was aerosolized and suspended in the air within a drum, and on surfaces four hours, 24 hours, and 2–3 days after it was deposited to copper, cardboard, and steel or plastic, respectively. SARS-CoV lasted about as long, although it lost viability sooner on cardboard and more slowly on copper. The median half-life for SARS-CoV-2 was 13 hours on steel and 16 hours on plastic.

“It’s a solid piece of work that answers questions people have been asking,” Julie Fischer, a microbiologist at Georgetown University who was not involved in the study, tells the AP. “What we need to be doing is washing our hands, being aware that people who are infected may be contaminating surfaces,” and not touching our faces.

As of today, more than 125,000 cases of COVID-19 have been reported worldwide, including 4,617 deaths, according to data from the European Centre for Disease Prevention and Control.

David Weber, an epidemiologist and infectious disease expert at the University of North Carolina at Chapel Hill who was not involved with the new research, called the study “excellent” in an interview with Buzzfeed, but notes that it can’t explain how risky contaminated surfaces are. “Does that account for 0.01% of transmissions or 15% of transmissions?” Weber says. “We don't know how frequent it is.” He also cautions that the lab conditions might not precisely recapitulate what happens in the real world.

Kerry Grens is a senior editor and the news director of The Scientist. Email her at kgrens@the-scientist.com.