Coronavirus pandemic: COVID-19 can survive in the air for nearly 3 hours, warn scientists
The new coronavirus can survive in the air for almost three hours, according to an analysis by US scientists. The team, which included experts from the National Institutes of Health (NIH) and US Centers for Disease Contol and Prevention (CDC), also found that the virus can remain viable on surfaces such as plastic and steel for up to three days.
The experts compared COVID-19 with SARS-CoV or severe acute respiratory syndrome (SARS)-associated coronavirus and the viability of these viruses on different surfaces and in the air.
“We investigate the stability of viable HCoV-19 (that is, COVID-19) on surfaces and in aerosols in comparison with SARS-CoV-1. Overall, stability is very similar between HCoV-19 and SARS-CoV-1. We found that viable virus could be detected in aerosols up to 3 hours post aerosolization, up to 4 hours on copper, up to 24 hours on cardboard and up to 2-3 days on plastic and stainless steel,” said the researchers in their findings, a pre-print version of which has been published in medRxiv.
The team includes experts from the National Institute of Allergy and Infectious Diseases (NIAID), NIH, Hamilton; Princeton University, US; University of California, Los Angeles; National Center for Immunization and Respiratory Diseases, CDC, Atlanta; and Fogarty International Center, NIH, Bethesda.
Both viruses showed markedly longer viability on stainless steel and polypropylene. “HCoV-19 and SARS-CoV-1 exhibited similar half-lives in aerosols, with median estimates around 2.7 hours. Both viruses show relatively long viability on stainless steel and polypropylene compared to copper or cardboard. The median half-life estimate for HCoV-19 is around 13 hours on steel and around 16 hours on polypropylene,” says the team.
According to the World Health Organization (WHO), the new coronavirus is a respiratory virus, which spreads primarily through droplets generated when an infected person coughs or sneezes, or through droplets of saliva or discharge from the nose.
So far, COVID-19 has infected over 128,000 people and over 4,700 have died from the disease globally.
In a previous study, researchers had analyzed various studies on coronaviruses and they found that these viruses are capable of surviving on surfaces for four to five days. The current study provides conclusive evidence that COVID-19 can survive on different types of surfaces.
COVID-19 has been detected in upper and lower respiratory tract samples from patients, with high viral loads in upper respiratory tract samples. Therefore, virus transmission via respiratory secretions in the form of droplets (greater than 5 microns) or aerosols (less than 5 microns) appears to be likely, say experts.
“Virus stability in air and on surfaces may directly affect virus transmission, as virus particles need to remain viable long enough after being expelled from the host to be taken up by a novel host. Airborne (or fomite) transmission were thought to play important roles in the epidemiology of the two zoonotic coronaviruses that emerged this century, SARS-CoV and MERS-CoV,” say researchers.
Accordingly, for the study, the team evaluated the “aerosol stability” COVID-19 and SARS-CoV for up to three hours in aerosols and up to seven days on different surfaces.
“Taken together, our results indicate that aerosol and fomite transmission of COVID-19 is plausible, as the virus can remain viable in aerosols for multiple hours and on surfaces up to days,” says the study.
However, the new study does not say whether people can become infected by breathing it in from the air.
“We experimentally generated aerosols and kept them afloat in a drum. This is not evidence of aerosol transmission,” tweeted study author Neeltje van Doremalen. He is a scientist at the Laboratory of Virology, Division of Intramural Research, NIAID.
The virus is most likely to spread from person to person between people who are in close contact with one another (within about six feet).
Person-to-person transmission can also happen through respiratory droplets produced when an infected person coughs or sneezes. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs, says the CDC.
The WHO and CDC have also advised that people should avoid touching their eyes, nose and mouth, and wash their hands frequently. This is a major and common way a person can pick up infections like COVID-19. This is because, throughout the day, people touch many surfaces — chairs, doorknobs, ATM or elevator buttons, subway poles — where viruses, including that of COVID-19, can linger for days.