The virus responsible for COVID-19 can remain viable for hours while airborne and for days on surfaces, researchers found.
SARS-CoV-2, the virus causing COVID-19, was viable in aerosols for 3 hours, and remained detectable on plastic and stainless steel surfaces for up to 72 hours, reported Vincent Munster, PhD, of the National Institute of Allergy and Infectious Diseases in Hamilton, Montana, and colleagues, writing in a New England Journal of Medicine letter.
Most ominously, the authors found a number of similarities in aerosol and fomite transmission between this virus and SARS-CoV-1, which caused the initial SARS disease, and noted, "these forms of transmission were associated with nosocomial spread and super-spreading events" in SARS.
Research about COVID-19 transmission via surfaces has been conflicting, with reports from Hong Kong and Singapore showing varied results.
Munster and colleagues evaluated the stability of this COVID-19 virus compared with SARS-CoV-1 as the most closely related coronavirus. They used 10 experimental conditions with the two viruses in five environmental conditions: aerosols, plastic, stainless steel, copper, and cardboard.
Notably, they found SARS-CoV-2 remained viable in aerosols, with a reduction in infectiousness over time similar to SARS-CoV-1, the authors said. It was less stable on copper and cardboard, and when it was detected in plastic and stainless steel, "the virus titer was greatly reduced," again similar to SARS-CoV-1 after 72 hours.
However, the virus causing COVID-19 infection had a longer half-life on cardboard than SARS-CoV-1, they said.
Virus viability was assessed in the current study via endpoint titration on Vero E6 cells, a method several of the same authors used previously with MERS coronavirus.
"Estimated differences in the half-lives of the two viruses were small, except for those on cardboard," Munster and colleagues wrote, though data were "noisier" for cardboard, meaning there was a larger variation, so caution was urged in interpreting these results.
The authors concluded aerosol and fomite transmission of SARS-C0V-2 was "plausible" and may help inform COVID-19 mitigation efforts.
Disclosures
This study was supported by the Intramural Research Program of the National Institute of Allergy and Infectious Diseases, NIH.
Munster disclosed no conflicts of interest.
Other co-authors disclosed support from Defense Advanced Research Projects Agency (DARPA), National Science Foundation, and Strategic Environmental Research and Development Program.
Primary Source
New England Journal of Medicine
Source Reference: van Doremalen N, et al "Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1" N Engl J Med 2020; DOI: 10.1056/NEJMc2004973.