How COVID-19 is transmitted through aerosols

A new study presented at the International Conference for High Performance Computing, Networking, Storage, and Analysis (SC21) has investigated how the coronavirus (particularly its Delta variant) is transmitted through aerosols – tiny air particles that can float in the air for hours and can travel long distances.

In the first year of the pandemic, scientists thought COVID-19 is transmitted mainly through saliva droplets that were released through coughing or sneezing, and traveled very short distances before falling to the ground. This understanding of the propagation of the disease was crucial for deciding upon social distancing measures such as maintaining a two-meter distance between people.

However, more recent research brought some rather bad news: COVID-19 appears to be airborne – that is, transmitted through aerosols. These particles, which are much smaller than droplets, can linger in the air for hours. They are also released through breathing.

“What we learned during the pandemic is that aerosols were one of the main drivers in spreading the virus and that their importance in the transmission of many other respiratory pathogens has been systematically underappreciated,” said study co-author Dr. Robert “Chip” Schooley, a professor in the Department of Medicine at UC San Diego School of Medicine.

Together with a team of researchers from all over the world, Dr. Schooley performed large-scale simulations of how the coronavirus is transmitted through aerosols. By using Oak Ridge National Laboratory’s supercomputer Summit, the scientists visualized with great accuracy aerosols containing the coronavirus, together with mucins, lung surfactant, water, and ions.

“This new computational microscope allows us to see what happens to the virus—how it moves, how it stays infectious during flight,” explained study lead author Rommie Amaro, a professor of Chemistry and Biochemistry at UC San Diego. “There is something very powerful about being able to see what something looks like, seeing how components come together—it fundamentally changes the kinds of questions people even think to ask.”

One of the hypotheses that the researchers are currently testing is whether the fact that the Delta variant interacts so well with mucins – polymers lining the wet surfaces of the body and help protecting viruses against harsh external elements such as sunlight – could explain its high transmissibility. 

“The more we learn about aerosols and how they host viruses and pollutants, such as soot, that have adverse health impacts, the better positioned we are to create effective treatment and mitigation measures. This benefits the public health and wellbeing of people around the world,” concluded Dr. Schooley.

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By Andrei Ionescu, Earth.com Staff Writer