The main modes of transmission of the new coronavirus are well known: via human respiratory droplets (when symptomatic people cough or sneeze) and direct contact. However, there is still uncertainty about its potential of spreading via aerosol transmission.
To investigate the aerodynamic nature of the new coronavirus, a team of researchers at Wuhan University set up aerosol traps in and around two government-designated Covid-19 hospitals in February and March this year.
They found that while the virus’s RNA in aerosols had low detection levels in the hospitals’ isolation wards and ventilated patient rooms, there was a higher level in the patients’ toilet areas.
The results were published in the journal Nature.
MedicineNet defines viruses as "small particles of genetic material (either DNA or RNA) that are surrounded by a protein coat", and explain that there are six classes of viruses: DNA viruses constitute classes I and II, and RNA viruses make up the remaining classes.
An article by ScienceDirect further explains that RNA viruses are known for typically rapid reproduction, followed by moving on to a new host. Coronaviruses are a large family of RNA viruses that cause diseases in mammals and birds, including potentially fatal human respiratory infections, such as what we're seeing with Covid-19.
Better ventilation and routine disinfection crucial
Lead researcher, Professor Lan Ke, director of the State Key Laboratory of Virology at Wuhan University, and his colleagues focused their research on two Wuhan hospitals that were exclusively being used for treating Covid-19 patients: Renmin Hospital of Wuhan University, and Wuchang Fangcang Field Hospital.
Their results revealed that the hospitals’ patient toilets had high levels of viral RNA, while the levels were much lower in the patients’ wards. They attributed this difference to the higher ventilation and air exchange, as well as effective isolation, in the patients’ wards, whereas the toilets had rather poor ventilation.
The team also took it a step further and looked at the viral RNA concentrations in areas used by medical staff to remove their protective apparel and equipment, and found particularly high levels. This, they suggest, may mean that the virus-laden aerosols can become re-suspended in the air.
Overall, they conclude that the new coronavirus has the potential to spread by way of aerosols, and suggest that in order to reduce the risk of airborne exposure, measures such as routine disinfection and better ventilation could help to control the virus’s spread.
The new coronavirus in airborne droplets: what other research suggests
According to a previous Health24 article reporting on recent studies, infected people who cough, breathe or talk could spread "aerosolised" viral particles up to a four-metre radius. Research published in Environmental International also found that the virus can live in the air for a certain period of time, especially in indoor, crowded areas.
The research done thus far therefore serves as a reminder that physical distancing may be the best tool we have in fighting the Covid-19 pandemic, and maintaining this should help curb new cases.