The novel coronavirus can remain in the air for up to 3 hours and live on certain surfaces for up to three days, new research suggests.
Researchers from the National Institutes of Health, the U.S. Centers for Disease Control and Prevention (CDC), UCLA, and Princeton University stressed in their study (pdf) published Wednesday that the findings do not prove that anyone has been infected through breathing the virus from the air or by touching contaminated surfaces.
“We’re not by any way saying there is aerosolized transmission of the virus,” said study leader Neeltje van Doremalen at the National Institute of Allergy and Infectious Diseases. However, van Doremalen added that transmission in this way is theoretically possible as research suggests that the virus stays viable for long periods in those conditions.
The team used a nebulizer to put traces of the novel coronavirus in the air, to re-create what would happen if an infected person were to cough or make the virus airborne some other way.
Findings suggested that three hours later, a viable virus could still be detected in the air. Meanwhile, the virus survived on copper surfaces up to four hours later, and up to 24 hours later on cardboard. The virus was detected as viable on plastic and stainless steel surfaces up to two to three days later.
However, researchers said results they obtained from tests they did on the virus that caused the 2003 SARS outbreak were similar, therefore suggesting the differences in durability of the viruses do not account for how much more widely the novel coronavirus has spread.
The researchers suggest that the larger scale of the coronavirus outbreak could be contributed to evidence suggesting coronavirus infected patients “shed and transmit the virus while pre-symptomatic or asymptomatic.”
Other factors “likely to play a role include the infectious dose required to establish an infection, the stability of virus in mucus, and environmental factors such as temperature and relative humidity,” the study suggests.
The findings have not yet been peer reviewed by other scientists, and were posted on a site where researchers can quickly share their work before publication. However, if verified, the study’s findings would correlate with increasing evidence of “community spread” of the virus.
Julie Fischer, a microbiology professor at Georgetown University described the study as a “solid piece of work” that answers the public’s questions and highlights the importance of the hygiene advice that public health officials have been stressing.
“What we need to be doing is washing our hands, being aware that people who are infected may be contaminating surfaces,” Fischer said.
Van Doremalen suggested cleaning surfaces with solutions containing diluted bleach is most likely to kill the virus.
The coronavirus was on Wednesday declared a global pandemic by the World Health Organization (WHO), as the the UN health agency urged aggressive action from all countries to fight it. The virus, which causes the COVID-19 disease, has rapidly spread all over Europe, the Middle East, and parts of the United States.
While China, where the epidemic started, still has by far the most cases of the virus, with more than 80,000, Italy has the next highest number of cases with about 12,400, followed by Iran at around 10,000 infections, and South Korea with more than 7,800 cases, according to data from Johns Hopkins University.
“We have called every day for countries to take urgent and aggressive action. We have rung the alarm bell loud and clear,” WHO’s chief Tedros Adhanom Ghebreyesus said Wednesday.
“All countries can still change the course of this pandemic. If countries detect, test, treat, isolate, trace and mobilize their people in the response,” he said. “We are deeply concerned by the alarming levels of spread and severity and by the alarming levels of inaction.”
President Donald Trump later announced that the United States will impose a 30-day travel ban on travelers from Europe amid coronavirus concerns.
The ban will come into effect on Friday at midnight and excludes non-Schengen countries like the United Kingdom and Ireland, as well as returning Americans who have had “appropriate screenings” for the virus.
The Associated Press contributed to this report.