A Loud Voice Can Be a Virus Ally

when Americans should expect a widely available coronavirus vaccine. In an interview today, Paul Mango, Deputy Chief of Staff for Policy at the Department of Health and Human Surfaces, offered a very ambitious timetable. He said every American could be able to get a shot by the end of March. His remarks came after President Donald Trump set in a televised town hall event last night that a vaccine could

be approved in three or four weeks. But the director of the Centers for Disease Control and Prevention, Robert Redfield, gave Senate testimony today and he was less optimistic than Mango or Trump. His estimate was that most Americans wouldn't be able to get a shot of an effective vaccine

until the second or third quarter of next year. Astra Zenica's vaccine trial remains paused in the US for a regulatory review of an incident where a participant developed unexplained neurological symptoms, including limb weakness, but the company said the symptoms probably weren't related to the shot itself. That's according to a letter the company sent to participants in the study. The letter reads quote After considering the information, the independent

reviewers recommended the vaccinations should continue. India's virus cases reached the five million mark with the addition of more than ninety thousand new cases. The virus has been spreading in India at one of the fastest paces in the world. India has the third highest death toll from COVID nineteen, trailing the US and Brazil. The real number of infected and dead in India from COVID nineteen is likely far higher than the official numbers due to under reporting and

inadequate testing. India's strict lockdown in clemented in late March to contain the outbreak, led to the biggest economic contraction of any major economy and now for today's main story. We've heard there are many things we can do to reduce the spread of the coronavirus, staying six ft away from someone else, washing our hands, and wearing a mask. But there's something else we can also do. Talk less.

Speaking is a powerful generator of aerosols, the fine particles emitted from our mouths that can harbor the stars Cove two virus and potentially linger for hours in poorly ventilated spaces. Turns out, shutting up can help shut those particles down, and as Bloomberg Senior editor Jason Gale found out, it few must speak. It's safer if you do it softly. Aerosols are tiny particles emitted from our respiratory tracks that

can stay aloft in ambient air for hours. There's been some debate about the role virus, light and eborne particles play and transmitting the COVID nineteen causing coronavirus. So I asked Bill Riston, party, professor of chemical engineering at the University of California, Davis, what we know about aerosols in

the spread of the pandemic disease. That's a complicated question, of course, right because the contact racing referred so much about that 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 those through a handshake or through them coughing your face or just talking and releasing infectious aerosol particles that travel across the room. But 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 of the people who attended got infected just during a two n fur choir practice, and you know choir practice that's associated with loud vocalization. Then there was the Knees lunch in a restaurant in Guango, China, in which Tan Dinas came down with COVID nineteen. They

had video evidence, which is really great. They showed that some of the people who got infected did not directly interact with the index case except by a virtue of the fact they're sharing the same air. Um, so they like did not you know, talk that didn't face to face and all that. So that's another piece of evidence for some type of long range transmission, and the expertory particles is the prime suspect. Then there have been outbreaks and bars whole Center and a cafe in South Korea

and a bus in China. The whole focused attention on potentially infectious particles emitted from the respiratory tract. I asked Bill, how are these produced? There's at least three modes of respiratory droplet or respiratory particle generation. You know, sometimes you're you're talking and you see little drops of fluid come out. That's the so called oral mode, and that's mostly saliva um, an old fashioned word to spittle. Those those droplets if you can feel them hitting somebody or if you can

see them. Relatively speaking, they're huge, way bigger than like say, fifty micrones, So they're like big boulders basically. And that's just one mode. The other two modes refer to much smaller particles that you can't see with the naked eye. One of them comes from the campillaries that line the

bronchials in the far reaches of the lungs. When you exhale and you squeeze everything down your lungs, these little capillaries come together, kind of pinched together, and then you inhale and they expand and there's respiratory fluid lining those. And so when you do that in expanse, you have a little fluid film that kind of pinches off and leaves little satellite droplets, your daughter droplets that are now exhaled with your air. Bill says, these particles are about

one micron in diameter. You know, I don't have much hair, but a typical human hair is about a hundred microns, so it's a hundred times smaller than the diameter of human hair. And so just breathing releases some of those. The other the third and final mode is the larrangel mode, so at the vocal chords. So when somebody says, uh, what's actually happening is you have these like little vocal words are opening and shutting at the frequency of your your pitch right, So I have kind of a deep voice.

It's about a hundred twenty hurts. That means when I'm saying uh, literally, it's going like this a hundred twenty times a second. And these also have fluid lighting them. I should add here that Bill's lab has two high speed cameras that can capture images at more than one hundred thousand frames per second. He also has various optical and laser systems for visualizing the micro droplets that have

created when we speak. So right now, as I've been talking, I've been emitting particles in the room right in front of me. And 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 in these micron skill So you have like a little little tiny bits of stunt, you know, basically floating around in the air

that could be carrying the virus. The Bill's researchers showing that certain things can vary the emission of expertory particles. We found that speaking releases much more than breathing. And we went even further, and what we showed is that like how many particles emitted doing speech is a very strong function of how loud you are. So if you speak really loud, you emit a ton of way more than if you than if you required if you whisper. And some folks just emit a lot of particles. Bill says,

some people are super emitters. So for whatever reason, um, some individuals when they talk just amit an order of magnitude more factor tend more than other people. And Bill says when some people cough for whatever reason, why more comes out. But these supermit is super spreaders of the coronavirus. That's a very challenge hypothesis to test post facto from an outbreak, but it's definitely a hypothesis that wants more investigation.

If I was the virus in China affect as many people, I'd want to a super emitter who also was a super grower the virus, or like the virus was very successful, so you had a very high viral concentrations. And then I make sure if I was a 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 a choir practice and have them sing and just vocalize as

much as possible for a very long time. And I'd also tell the people to shut off the ventilation, uh so so that you know, to get the airborne viral concentration as high as possible. But also found that saying certain words it's associated with more particles admitted employs. It's like Papa produced more than fricatives like fafa but in general it was less important. Again if I was if I was a virus, I wouldn't care so much about what the word you're saying is. I would want to

be in somebody who's saying it loudly. Right, So, in other words, minor changes and how loud you're articulating swamp out of the differences and what you're articulating. Does this mean people should be quiet for the sake of public health. 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 of rooms like hospital wedding rooms. Back then, the report is looking at like that's crazy, but I think I think there is great to that. Now in September, that recommendation is sounding kind of sensible. We know that maintaining a physical distance, wearing a face mask, and thorough handwashing all helped to reduce the risk of spreading the coronavirus, but none is fail safe. It's doing them all together and quietly and offers the best chance at driving the

pandemic into submission. That was Jason Gail, And that's it for our show Today. For coverage of the outbreak from one D and twenty bureaus around the world, visit bloomberg dot com Flash Coronavirus and if you like the show, please leave us a review and a rating on Apple Podcasts or Spotify. It's the best way to help more listeners find our global reporting. The Prognosis Daily edition is produced by topor foreheads Jordan gas Pure, Magnus Hendrickson, and

me Laura Carlson. Today's main story was reported by Jason Gale. Original music by Leo Sidrin. Our editors are Rick Shine and Francesca Levi. Francesca Levi is Bloomberg's head of podcasts. Thanks for listening.