Wuhan Study: Coronavirus RNA Found In Air Droplets

A new study from Wuhan presents evidence for viral RNA in the air, but whether this material has the potential to infect was not assessed.

AsianScientist (Apr. 27, 2020) – Environmental monitoring of two hospitals and some public areas in Wuhan, China, has revealed the presence of airborne SARS-CoV-2 RNA. The results were published in the journal Nature today.

To date, SARS-CoV-2 has been shown to be transmitted via close contact with infected individuals, contact with contaminated surfaces, or inhalation of respiratory droplets from infected individuals. Whether there is further potential for SARS-CoV-2 to spread through the air has been less clear.

To investigate the aerodynamic nature of SARS-CoV-2, Professor Lan Ke, director of the State Key Laboratory of Virology at Wuhan University, and colleagues set up aerosol traps in and around two government-designated COVID-19 hospitals in February and March 2020. The existence of SARS-CoV-2 in aerosol samples was determined through the quantification of RNA genetic material.

Both hospitals were exclusively used for COVID-19 patient treatment during the outbreak: the Renmin Hospital of Wuhan University was a Grade-A tertiary hospital designated for the treatment of patients with severe symptoms, while the Wuchang Fangcang Field Hospital was a field hospital converted from a stadium to quarantine and treat patients with mild symptoms.

In general, the concentration of viral RNA in ventilated patient wards was found to be very low, which the authors attribute to effective isolation and high air exchange. On the other hand, patient toilets, which were not ventilated, had elevated concentrations of airborne viral RNA. The authors found that RNA was especially concentrated in areas used by medical staff to take off protective apparel, which suggests that virus-laden aerosols can become resuspended in the air when protective apparel is removed.

Concentrations of SARS-CoV-2 RNA in public areas outside the hospitals—such as residential buildings and supermarkets—were generally low, with the exception of two areas that saw large crowds passing through. The authors suggest that individuals infected with SARS-CoV-2 within these crowded areas may have contributed to the viral aerosols detected.

“The findings from this study provide the first real-world investigation on the aerodynamic characteristics of airborne SARS-CoV-2 in Wuhan implemented with strict quarantine and travel restrictions during the peak of the COVID-19 outbreak,” the authors wrote. They noted that the sample size in the study was small, with fewer than 40 samples from 31 locations.

The authors recommend for attention to be placed on the proper ventilation and sterilization of toilets; personal protection measures such as wearing masks and avoidance of crowds to reduce the risk of airborne virus exposure; careful sanitization of high risk areas in hospitals; and sanitization of protective apparel before removal.

“Although we have not established the infectivity of the virus detected in these hospital areas, we propose that SARS-CoV-2 may have the potential to be transmitted via aerosols,” the authors speculate, adding that future research exploring the infectivity of aerosolized virus particles would be necessary.

The article can be found at: Liu et al. (2020) Aerodynamic Analysis of SARS-CoV-2 in Two Wuhan Hospitals.


Source: Nature; Photo: Unsplash.
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