Ask A Doctor: How Big A Threat Is Aerosolized Spread Of The Coronavirus?

A UT Health San Antonio physician answers listeners’ questions about their health during the coronavirus pandemic.

By Michael Marks & Caroline CovingtonSeptember 24, 2020 10:59 am,

In this installment of Ask a Doctor, UT Health San Antonio physician Dr. Fred Campbell answers more of Texas Standard listeners’ most pressing questions about the coronavirus.

What’s the latest research about coronavirus spreading through aerosol particles?

The Centers for Disease Control and Prevention alerted the public last week that the coronavirus can spread beyond 6 feet through aerosolized particles, but then it removed that guidance on Monday. Campbell said based on what he knows about the latest research, it’s rare that the virus could infect people after traveling long distances through the air. Spread through respiratory droplets between people in close proximity is still the biggest concern, and maintaining a 6-foot distance and wearing a mask is the best way to prevent that kind of spread.

“Those aerosols do contain virus particles, but for whatever reason, they don’t appear to be infectious,” he said.

Can air conditioning and ventilation systems increase the spread of the coronavirus?

This has been an important issue especially for airlines, which are looking to protect passengers’ health through better airflow. But Campbell said so far, the research doesn’t show that ventilation systems can spread an infectious form of the virus over long distances. That means, he said, that you wouldn’t be more likely to catch the virus because of air that was circulated from another part of an airplane, or from a different room in a building.

“The HVAC, although it could very well move particles around, particularly the aerosolized particles … I think that the infectivity rate among the studies that have been looked at have been extremely low with that kind of transmission,” he said.

Is a gathering inside a garage with the door open as safe as gathering outdoors?

Campbell said ventilation is key when it comes to gathering with others during the pandemic. Outdoors is preferable, but he said a garage could work if the door is open wide. Guests should still wear masks and practice social distancing.

“A garage would be as close to an outside environment as one could get,” Campbell said.

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