New coronaviruses are highly infectious and have multiple routes of transmission. Recently, a team of researchers from Wuhan conducted environmental monitoring of two hospitals and selected public areas and demonstrated that nucleic acids of the new coronavirus could be detected in the air. The study noted that the newly discovered evidence corroborates previous suggestions that careful maintenance of hygiene and cleanliness, good ventilation, and avoidance of aggregation can reduce the risk of airborne virus exposure.
To confirm the possibility of further airborne transmission of the new coronavirus, a research team led by Professor Lan Ke of Wuhan University conducted a study from February to March 2020 at two hospitals designated for the treatment of new coronavirus pneumonia. One of them was a tertiary hospital that received critically ill patients, and the other was a square-cabin hospital that received mildly ill patients. Researchers set up aerosol capture devices in and around each of the two hospitals.
The results of the study showed that the airborne viral nucleic acid concentrations were very low overall in the ventilated patient areas. The study authors attributed this to effective isolation and high efficiency of air exchange. In contrast, viral nucleic acid concentrations were higher in toilets used by patients who were not ventilated. The authors also found that viral nucleic acid concentrations were particularly high in areas where health care workers disconnected protective equipment, implying that virus-containing aerosols could be resuspended in the air after the protective equipment was removed.
It is noteworthy that the concentration of neocoronavirus nucleic acid in the area of health care workers decreased to undetectable levels after the implementation of strict cleaning and disinfection procedures.
In public areas outside the hospital, such as residential houses and supermarkets, neo-coronavirus nucleic acid concentrations were not high overall. However, neo-coronavirus nucleic acid concentrations remained high in two areas where large crowds passed through, including an open outdoor area near one of the hospitals mentioned above. The authors suggest that the presence of neo-coronavirus-infected individuals in these crowded areas may have contributed to the production of viral aerosols.
The study did not investigate whether airborne neocoronavirus nucleic acids may have been infectious, and restricted access to the hospital during the peak of the outbreak limited the number of samples that could be obtained, with nearly 40 samples obtained from only 31 loci.
Despite these limitations, the researchers emphasized in their conclusions that their results suggest that indoor ventilation, open spaces, disinfection of protective clothing, and proper use and disinfection of toilet areas can be effective in reducing airborne neocoronavirus nucleic acids and reducing the risk of infection.
