Coronavirus May Spread as Aerosol, New Research Suggests

Because it is a relatively new virus in humans, information about coronavirus associated with COVID-19 is still relatively limited and research is ongoing to establish the ways in which it is transmitted and how it affects the human body. Some of this new research focusing on transmission is suggesting that the virus new spread as an aerosol, potentially allowing it to spread much farther than previously believed. Here’s what you need to know about this ongoing research and what it could mean for the current pandemic.


What Have the New Studies Found?


The research suggesting aerosol transmission of coronavirus centers mostly on two major studies. The first was a paper published in March in the New England Journal of Medicine that established the new coronavirus strain was able to survive in airborne aerosols for at least 3 hours under the right conditions. Although the paper showed viability in aerosol form, the experiment was conducted by mechanically creating the aerosol.


More recent research from the University of Nebraska, however, provides more evidence that the COVID-19 coronavirus could be traveling from person-to-person in an aerosolized form. These new findings resulted from a study in which the areas around active COVID-19 patients were monitored for viral contamination. In that study, researchers found viral contamination in the air and in the hallways outside of patient rooms. These findings indicated that COVID-19 patients could be producing the kind of aerosols originally found to be viable in the earlier NEJM paper.


Droplets Vs. Aerosol: What’s the Difference?


On the surface, droplets and aerosols may sound similar, but there is an important distinction. Droplets are larger particles of moisture, typically produced when coughing or sneezing. They are large enough that they fall to the ground or onto nearby surfaces shortly after being ejected from a patient, as they do not have enough time to evaporate before gravity pulls them down.


Aerosols, on the other hand, are much smaller and can be formed through normal exhalation. They evaporate before falling to the ground, thus allowing tiny particles in them (such as viruses), to become airborne. These particles are then free to travel much farther than they could in droplets, as evidenced by the finding of viral contamination outside the rooms of COVID-19 patients in the University of Nebraska study.


What Do These New Findings Mean?


Up to now, health officials have mostly focused on the spread of coronavirus through droplets. Prevention guidelines such as the 6-foot social distancing rule and the recommendation to wear a cloth facial covering outside of the home are geared toward preventing droplet spread, since droplets can’t travel especially far and can’t easily pass through even a non-medical grade barrier.


Aerosol spread would mean that COVID-19 is both more difficult to prevent and more transmissible than previously thought. In light of recent evidence suggesting that at least 1 in 4 cases of COVID-19 is asymptomatic, aerosol transmission would also make it likely that a person carrying the disease could easily infect many others without ever realizing it.


How Certain Is This New Research?


To be clear, the NEJM paper and the new findings from the University of Nebraska provide only circumstantial evidence that viable coronaviruses could be spreading as aerosols. As the U of N release itself notes, further research is needed to definitively prove that the COVID-19 coronavirus is spreading in this way. Experts have also cautioned that it could be years before the transmission pathway of this virus is fully mapped.