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Since earlier during the current Covid-19 outbreak, there has been uncertainty about how exactly the coronavirus spreads, besides from direct contact with infected respiratory droplets.
A paper published in March 2020 investigated the stability of the virus in an aerosol setting, and the research came to the general conclusion that the virus can live in the air for a certain period of time, especially in indoor, crowded areas.
Now, research from world-leading air quality and health expert Professor Lidia Morawska and Professor Junji Cao from Chinese Academy of Sciences called on health bodies to initiate research into airborne transmission of the novel coronavirus, according to a news release.
Their research was published in Environmental International.
Non-contact transmission
"National health bodies responsible for controlling the pandemic are hampered by not acknowledging the research evidence of airborne transmission of viable virus droplets, that was conducted after the SARS 2003 outbreak," Professor Morawska said.
"Now is the ideal time to conduct research into how viruses can travel on the airflow, because there are many similarities between the coronavirus that caused SARS and the Covid-19 coronavirus and therefore it is highly likely that Covid-19 spreads by air.”
"Analysis of the initial pattern of Covid-19 spread in China reveals multiple cases of non-contact transmission, especially in areas outside Wuhan,” the researchers stated.
What is recommended?
In their article, researchers suggest the following measures for authorising bodies:
- Increase the ventilation in shared indoor spaces.
- Make use of natural ventilation where possible – open windows etc.
- Avoid recirculation of air.
- Avoid standing in another person’s direct airflow.
- Try and minimise the number of people sharing a space, where possible,
- Focus on adequate ventilation, specifically in old-age homes, hospitals, shops, offices and schools.
What makes the droplets so airborne?
"A WHO review (2009) of the evidence found viral diseases can be transmitted across distances in indoor environments by aerosol or airborne infection and can result in large clusters of infection in a short period," Prof Morawska said.
According to her, the liquid content of virus droplets starts to evaporate immediately after being exhaled. Some of the droplets can become so small they can travel on air currents instead of simply falling to the floor.
"Such small droplets can carry their viral content metres, even tens of metres, away from the infected person."
She calls upon authorities to research air transmission in specific air flow situations to understand the full impact of airborne infection.
Professor Morawska also said it was difficult to directly detect viruses travelling in the air.
"We have already lost valuable time by ignoring this method of spread and we should act on the presumption that Covid-19 is spreading on the air."
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