Can Shutting Up Stop the Spread of Covid-19?

Speaking is a powerful generator of aerosols -- the fine particles emitted from our mouths and noses that can harbor the SARS-CoV-2 virus and potentially linger for hours in poorly ventilated spaces. Turns out, shutting up can help shut those particles down.

William Ristenpart is a professor of chemical engineering at the University of California, Davis and says there's tiny bits of stuff floating in the air that could be carrying the virus.

“The contact tracing we've heard so much about that tells you who you likely got it from and when you likely got it. But it does not tell you by itself how you got it, whether that's through a handshake or through coughing in your face or just talking and releasing infectious aerosol particles that travel across the room.”

The indirect evidence implicating aerosols is mounting.

“The very first one that opened a lot of people's eyes was that outbreak of the choir practice up at Washington State. I think it was 87 percent of the people who attended got infected just during a two and half hour choir practice that's associated with loud vocalization.”

Wiiliam’s lab has two high-speed cameras that can capture images at more than 100,000 frames per second. He also has various optical and laser systems for visualizing the micro droplets that are created when we speak.

“So right now, as I've been talking, I've been emitting particles out of the room right in front of me. And so even though they're really tiny, too tiny to see, they're huge compared to the virus. So the virus can very happily be carried along. They're so small, they evaporate extremely rapidly, leaving behind just the nonvolatile things like the proteins and the salts, basically the mucus. So you have like little little tiny bits of stuff, you know, basically floating around in the air that could be carrying the virus.”

And some people just emit a lot of particles, William says.

“Some people are super emitters. So for whatever reason, some individuals, when they talk just emit an order of magnitude more, a factor of 10 more than other people.”

And, William says, when some people cough, for whatever reason, way more comes out. But are these super emitters super spreaders of the coronavirus?

“That's a very challenging hypothesis to test post-facto from an outbreak. But it's definitely a hypothesis that warrants more investigation. If I was the virus and trying to infect as many people, I'd want a super emitter who also was a super grower of the virus or like the virus was very successful. So you had very high viral concentrations. And then I'd make sure, if I was the virus again, that I didn't make the person symptomatic. So they looked very healthy. And I'd have them go to a bar or choir practice and have them sing and vocalize as much as possible for a very long time. And I'd also tell people to shut off the ventilation system so that we get the airborne vial concentrations as high as possible.”

Does this mean people should be quiet for the sake of public health?

William explains, “I was advocating to some journalists who interviewed me back in April, and I said, I think we should start thinking about recommending people don't talk so much, especially in high-risk areas like hospital waiting rooms, you know, things like that. And back then, the reporters looked at me like I was crazy. But I think there is great merit to that.”

Now several months later, that recommendation is sounding quite sensible. We know that maintaining a physical distance, wearing a face mask, and thorough hand washing all help to reduce the risk of spreading the coronavirus. But, none is failsafe. It’s doing them all together -- and quietly -- that offers the best chance at driving the pandemic into submission.

Subscribe to our YouTube channel

QUICKTAKE ON SOCIAL:

Follow QuickTake on Twitter: twitter.com/quicktake

Like QuickTake on Facebook: facebook.com/quicktake

Follow QuickTake on Instagram: instagram.com/quicktake

Subscribe to our newsletter

Email us at quicktakenews@gmail.com

QuickTake by Bloomberg is a global news network delivering up-to-the-minute analysis on the biggest news, trends and ideas for a new generation of leaders.