Mar 13, 2020 05:45 AM

Covid-19 Virus Stays Viable in Air, on Surfaces, Study Shows

Photo: Bloomberg
Photo: Bloomberg

A study of environmental samples from the epicenter of Covid-19 outbreak sheds light on how the novel coronavirus can linger in the air and on surfaces, suggesting additional transmission pathways for the virus.

In the first field research of its kind, a group of researchers in Wuhan, Shanghai and Hong Kong analyzed 35 samples from hospitals and public areas in Wuhan, the central China city where the new disease first emerged. They measured the amount of viable virus carried by aerosol — tiny particle droplets in the air.

The study showed that the coronavirus that causes Covid-19, known as SARS-CoV-2, can remain viable in the air or on solid surfaces with the potential to infect people, according to a preprint of the study published by the biology research archive bioRxiv. The researchers didn’t say how long the pathogen may remain viable in the air and on surfaces.

Human respiratory droplets and direct contact are believed to be the main ways for transmission of the virus. The disease has sickened more than 125,000 people worldwide, making it the first pandemic declared by the World Health Organization since 2009.

In the absence of confirmed findings, experts have warned of possible aerosol transmission of the virus. China’s National Health Commission mentioned the possibility of aerosol transmission for the first time Feb. 5 in a Covid-19 treatment guide.

In the latest updated treatment guide issued March 4, the national health authority cautioned of potential transmission of virus through aerosols from feces and urine.

In the 2003 outbreak of the SARS coronavirus, a cousin of Covid-19, fecal transmission was believed to be the main cause of hundreds of cases at a Hong Kong residential complex, one of the areas hardest-hit by the disease.

The latest study in Wuhan provides evidence that the new virus can be passed through aerosols, especially from fecal transmission. By using a polymerase chain reaction (PCR) method to quantify the virus RNA genome and determine aerosol RNA concentration, the study found high concentrations of the virus in aerosol samples collected from patient toilets at two Wuhan hospitals, suggesting the possibility of fecal transmission.

High amounts of virus were also detected in aerosol samples from hospital rooms where medical workers removed protective apparel, indicating that the virus could accumulate on the surface of protective gear and be carried by medical workers into the changing rooms, according to the study.

Low amounts of virus were found in samples collected from public areas, despite higher readings in samples from the entrance of a shopping mall and the public zone of the Wuhan University Renmin Hospital, where patients gathered awaiting doctor interviews, the research found.

The findings suggested that the novel coronavirus can remain viable in aerosols and accumulate on surfaces, causing the risk of airborne transmission.

The researchers suggested that people avoid public gathering and wear face masks to reduce exposure to the risk of contagion. Room ventilation, open spaces and proper use and disinfection of toilets can also effectively limit aerosol transmission, they said.

Contact reporter Han Wei ( and editor Bob Simison (

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