The new coronavirus can survive for several hours in air particles and last days on surfaces, according to a new federally funded study published in the New England Journal of Medicine.
Researchers from the National Institutes of Health, Centers for Disease Control and Prevention, UCLA and Princeton University examined how long COVID-19 survives in the air as well as on copper, cardboard, plastic and stainless steel and then compared it with SARS, the coronavirus that emerged in late 2002 and killed nearly 800 people.
They found that COVID-19 was detectable in aerosols for up to three hours, up to four hours on copper and up to 24 hours on cardboard. The new coronavirus can also last up to three days on plastic and stainless steel, the scientists concluded, adding the amount of the virus left on those surfaces decreases over time. Aerosols are solid or liquid particles that hang in the air, including fog, dust, and gas commonly used in medical procedures like ventilation and nebulizers.
The results suggest "that people may acquire the virus through the air and after touching contaminated objects," Dr. Neeltje van Doremalen, a scientist from NIH and a lead researcher on the study, said in a press release announcing the findings Tuesday evening.
COVID-19 cases surpassed 200,000 worldwide on Wednesday as the new coronavirus continues to spread outside of China, the original epicenter of the outbreak.
Earlier this week, the World Health Organization said it was considering "airborne precautions" for medical staff after a study showed that COVID-19 can survive in the air in some settings.
The virus is transmitted through droplets, or little bits of liquid, mostly through sneezing or coughing, Dr. Maria Van Kerkhove, head of WHO's emerging diseases and zoonosis unit, told reporters during a virtual news conference on Monday. "When you do an aerosol-generating procedure like in a medical care facility, you have the possibility to what we call aerosolize these particles, which means they can stay in the air a little bit longer."
Health officials have known the respiratory disease spreads through human-to-human contact, droplets carried through sneezing and coughing as well as germs left on inanimate objects. The coronavirus can also become airborne, staying suspended in the air for hours, depending on the heat and humidity, they said.
The scientists in the new study said the stability of COVID-19 was similar to that of SARS, but unlike SARS, COVID-19 can be transmitted while a person doesn't have any symptoms.
Some scientists say the new coronavirus, which emerged from the Chinese city of Wuhan less than three months ago, is proving to be more contagious than SARS, which infected more than 8,000 people. The virus has already been shown to be much more contagious than the seasonal flu, which infects up to 49 million Americans a year alone.
"These findings echo those with SARS-CoV-1, in which these forms of transmission were associated with nosocomial spread and super-spreading events, and they provide information for pandemic mitigation efforts," the scientists said.