Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals

Abstract

Cite this article as: Liu, Y. et al. Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals. Nature https://doi.The ongoing COVID-19 outbreak has spread rapidly on a global scale. While the transmission of SARS-CoV-2 via human respiratory droplets and direct contact is clear, the potential for aerosol transmission is poorly understood 1-3 . This study investigated the aerodynamic nature of SARS-CoV-2 by measuring viral RNA in aerosols in different areas of two Wuhan hospitals during the COVID-19 outbreak in February and March 2020. The concentration of SARS-CoV-2 RNA in aerosols detected in isolation wards and ventilated patient rooms was very low, but it was elevated in the patients' toilet areas. Levels of airborne SARS-CoV-2 RNA in the majority of public areas was undetectable except in two areas prone to crowding, possibly due to infected carriers in the crowd. We found that some medical staff areas initially had high concentrations of viral RNA with aerosol size distributions showing peaks in submicrometre and/or supermicrometre regions, but these levels were reduced to undetectable levels after implementation of rigorous sanitization procedures. 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. Our results indicate that room ventilation, open space, sanitization of protective apparel, and proper use and disinfection of toilet areas can effectively limit the concentration of SARS-CoV-2 RNA in aerosols. Future work should explore the infectivity of aerosolized virus.

Consideration of the Aerosol Transmission for COVID‐19 and Public Health

“…Another hospital study raises concerns for SARS-CoV-2 being transported as aerosols from droplet contaminated surfaces. This concern was based on measurement data associated with removing personal protective equipment, cleaning floors, and moving staff (Liu et al, 2020). The study also found SARS-CoV-2 in the air in outdoor areas at the hospital entrance and in front of a department store; the authors conclude it is possible that asymptomatic individuals in these areas may have contributed to these results.…”

The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission

“…Here, we derive quantitative estimates for both the number and size of the droplets that remain airborne. Larger droplets, which are also abundant but associated with closeproximity direct virus transfer or fomite transmission (11), or which can become resuspended in air at a later point in time (12), are not considered here.…”

Protecting dental manpower from COVID‐19 infection

“…Decontamination of equipment and the care environment must be performed after each patient and should be carried out as per practice protocols. Decontamination of all areas of the practice including the toilets can effectively limit the concentration of SARS-CoV-2 RNA in aerosols (Liu et al, 2020). It is generally advisable to avoid the use of fans that re-circulate the air.…”