WEBVTT - A Loud Voice Can Be a Virus Ally 0:00:05.640 --> 0:00:10.639 Welcome to Prognosis. I'm Laura Carlson. It's day one and 0:00:10.760 --> 0:00:16.040 eighty nine since coronavirus was declared a global pandemic. Today's 0:00:16.040 --> 0:00:20.000 main story. The more we learn about the virus, the 0:00:20.079 --> 0:00:24.480 more ways we have to shift our behavior. The latest surprise, 0:00:25.480 --> 0:00:29.600 how loud we speak may matter for limiting the spread 0:00:29.600 --> 0:00:34.920 of the virus. But first, here's what happened in virus 0:00:34.960 --> 0:00:48.680 news today. Top US health officials offered conflicting estimates of 0:00:48.720 --> 0:00:54.200 when Americans should expect a widely available coronavirus vaccine. In 0:00:54.200 --> 0:00:58.160 an interview today, Paul Mango, Deputy Chief of Staff for 0:00:58.280 --> 0:01:02.240 Policy at the Department of Health and Human Surfaces, offered 0:01:02.360 --> 0:01:07.840 a very ambitious timetable. He said every American could be 0:01:07.880 --> 0:01:10.479 able to get a shot by the end of March. 0:01:12.560 --> 0:01:16.039 His remarks came after President Donald Trump set in a 0:01:16.120 --> 0:01:20.480 televised town hall event last night that a vaccine could 0:01:20.520 --> 0:01:25.759 be approved in three or four weeks. But the director 0:01:25.800 --> 0:01:29.479 of the Centers for Disease Control and Prevention, Robert Redfield, 0:01:29.520 --> 0:01:34.160 gave Senate testimony today and he was less optimistic than 0:01:34.280 --> 0:01:39.240 Mango or Trump. His estimate was that most Americans wouldn't 0:01:39.280 --> 0:01:42.240 be able to get a shot of an effective vaccine 0:01:42.640 --> 0:01:48.200 until the second or third quarter of next year. Astra 0:01:48.320 --> 0:01:53.160 Zenica's vaccine trial remains paused in the US for a 0:01:53.200 --> 0:01:58.320 regulatory review of an incident where a participant developed unexplained 0:01:58.520 --> 0:02:04.920 neurological symptoms, including limb weakness, but the company said the 0:02:05.000 --> 0:02:09.840 symptoms probably weren't related to the shot itself. That's according 0:02:09.880 --> 0:02:13.280 to a letter the company sent to participants in the study. 0:02:13.840 --> 0:02:19.240 The letter reads quote After considering the information, the independent 0:02:19.280 --> 0:02:26.120 reviewers recommended the vaccinations should continue. India's virus cases reached 0:02:26.320 --> 0:02:29.639 the five million mark with the addition of more than 0:02:29.760 --> 0:02:33.799 ninety thousand new cases. The virus has been spreading in 0:02:33.800 --> 0:02:37.160 India at one of the fastest paces in the world. 0:02:38.040 --> 0:02:41.600 India has the third highest death toll from COVID nineteen, 0:02:42.200 --> 0:02:47.200 trailing the US and Brazil. The real number of infected 0:02:47.400 --> 0:02:51.240 and dead in India from COVID nineteen is likely far 0:02:51.440 --> 0:02:55.440 higher than the official numbers due to under reporting and 0:02:55.600 --> 0:03:01.400 inadequate testing. India's strict lockdown in clemented in late March 0:03:01.520 --> 0:03:05.280 to contain the outbreak, led to the biggest economic contraction 0:03:05.520 --> 0:03:18.000 of any major economy and now for today's main story. 0:03:19.600 --> 0:03:22.200 We've heard there are many things we can do to 0:03:22.280 --> 0:03:26.120 reduce the spread of the coronavirus, staying six ft away 0:03:26.120 --> 0:03:30.120 from someone else, washing our hands, and wearing a mask. 0:03:30.919 --> 0:03:35.200 But there's something else we can also do. Talk less. 0:03:36.040 --> 0:03:40.280 Speaking is a powerful generator of aerosols, the fine particles 0:03:40.280 --> 0:03:43.240 emitted from our mouths that can harbor the stars Cove 0:03:43.440 --> 0:03:49.320 two virus and potentially linger for hours in poorly ventilated spaces. 0:03:50.280 --> 0:03:54.880 Turns out, shutting up can help shut those particles down, 0:03:55.920 --> 0:03:59.840 and as Bloomberg Senior editor Jason Gale found out, it 0:04:00.040 --> 0:04:04.240 few must speak. It's safer if you do it softly. 0:04:14.080 --> 0:04:17.560 Aerosols are tiny particles emitted from our respiratory tracks that 0:04:17.680 --> 0:04:21.479 can stay aloft in ambient air for hours. There's been 0:04:21.680 --> 0:04:24.480 some debate about the role virus, light and eborne particles 0:04:24.560 --> 0:04:28.200 play and transmitting the COVID nineteen causing coronavirus. So I 0:04:28.279 --> 0:04:31.120 asked Bill Riston, party, professor of chemical engineering at the 0:04:31.200 --> 0:04:35.039 University of California, Davis, what we know about aerosols in 0:04:35.080 --> 0:04:38.640 the spread of the pandemic disease. That's a complicated question, 0:04:38.680 --> 0:04:41.280 of course, right because the contact racing referred so much 0:04:41.279 --> 0:04:43.839 about that that tells you who you likely got it 0:04:43.880 --> 0:04:45.480 from and when you likely got it, but it does 0:04:45.520 --> 0:04:48.279 not tell you by itself how you got it, whether 0:04:48.320 --> 0:04:50.880 those through a handshake or through them coughing your face 0:04:51.040 --> 0:04:55.480 or just talking and releasing infectious aerosol particles that travel 0:04:55.520 --> 0:04:59.920 across the room. But the indirect evidence implicating aerosols is mounting. 0:05:00.400 --> 0:05:01.960 The very first one that opened a lot of people's 0:05:02.000 --> 0:05:04.760 eyes was that outbreak of the choir practice up at 0:05:04.760 --> 0:05:08.560 Washington State. I think it was of the people who 0:05:08.560 --> 0:05:11.760 attended got infected just during a two n fur choir practice, 0:05:12.200 --> 0:05:16.200 and you know choir practice that's associated with loud vocalization. 0:05:16.400 --> 0:05:20.000 Then there was the Knees lunch in a restaurant in Guango, China, 0:05:20.360 --> 0:05:23.400 in which Tan Dinas came down with COVID nineteen. They 0:05:23.400 --> 0:05:25.400 had video evidence, which is really great. They showed that 0:05:25.480 --> 0:05:28.560 some of the people who got infected did not directly 0:05:28.600 --> 0:05:32.760 interact with the index case except by a virtue of 0:05:32.760 --> 0:05:35.280 the fact they're sharing the same air. Um, so they 0:05:35.320 --> 0:05:38.120 like did not you know, talk that didn't face to 0:05:38.160 --> 0:05:40.920 face and all that. So that's another piece of evidence 0:05:40.960 --> 0:05:45.080 for some type of long range transmission, and the expertory 0:05:45.080 --> 0:05:50.080 particles is the prime suspect. Then there have been outbreaks 0:05:50.080 --> 0:05:53.320 and bars whole Center and a cafe in South Korea 0:05:53.520 --> 0:05:56.560 and a bus in China. The whole focused attention on 0:05:56.640 --> 0:06:01.440 potentially infectious particles emitted from the respiratory tract. I asked Bill, 0:06:01.640 --> 0:06:04.280 how are these produced? There's at least three modes of 0:06:04.880 --> 0:06:09.680 respiratory droplet or respiratory particle generation. You know, sometimes you're 0:06:09.680 --> 0:06:11.839 you're talking and you see little drops of fluid come out. 0:06:12.279 --> 0:06:15.000 That's the so called oral mode, and that's mostly saliva um, 0:06:15.279 --> 0:06:18.120 an old fashioned word to spittle. Those those droplets if 0:06:18.160 --> 0:06:20.640 you can feel them hitting somebody or if you can 0:06:20.680 --> 0:06:23.760 see them. Relatively speaking, they're huge, way bigger than like say, 0:06:23.800 --> 0:06:26.440 fifty micrones, So they're like big boulders basically. And that's 0:06:26.440 --> 0:06:29.520 just one mode. The other two modes refer to much 0:06:29.560 --> 0:06:32.240 smaller particles that you can't see with the naked eye. 0:06:32.720 --> 0:06:34.960 One of them comes from the campillaries that line the 0:06:35.000 --> 0:06:37.840 bronchials in the far reaches of the lungs. When you 0:06:37.920 --> 0:06:41.159 exhale and you squeeze everything down your lungs, these little 0:06:41.200 --> 0:06:44.960 capillaries come together, kind of pinched together, and then you 0:06:45.000 --> 0:06:49.120 inhale and they expand and there's respiratory fluid lining those. 0:06:49.120 --> 0:06:51.800 And so when you do that in expanse, you have 0:06:51.839 --> 0:06:54.719 a little fluid film that kind of pinches off and 0:06:54.800 --> 0:06:58.200 leaves little satellite droplets, your daughter droplets that are now 0:06:58.839 --> 0:07:01.880 exhaled with your air. Bill says, these particles are about 0:07:01.960 --> 0:07:04.800 one micron in diameter. You know, I don't have much hair, 0:07:04.880 --> 0:07:07.880 but a typical human hair is about a hundred microns, 0:07:08.080 --> 0:07:10.040 so it's a hundred times smaller than the diameter of 0:07:10.400 --> 0:07:12.880 human hair. And so just breathing releases some of those. 0:07:13.360 --> 0:07:16.320 The other the third and final mode is the larrangel mode, 0:07:16.360 --> 0:07:21.040 so at the vocal chords. So when somebody says, uh, 0:07:21.200 --> 0:07:24.280 what's actually happening is you have these like little vocal 0:07:24.400 --> 0:07:27.520 words are opening and shutting at the frequency of your 0:07:27.800 --> 0:07:30.119 your pitch right, So I have kind of a deep voice. 0:07:30.440 --> 0:07:32.360 It's about a hundred twenty hurts. That means when I'm 0:07:32.360 --> 0:07:34.960 saying uh, literally, it's going like this a hundred twenty 0:07:34.960 --> 0:07:38.760 times a second. And these also have fluid lighting them. 0:07:38.760 --> 0:07:40.840 I should add here that Bill's lab has two high 0:07:40.880 --> 0:07:44.160 speed cameras that can capture images at more than one 0:07:44.240 --> 0:07:47.760 hundred thousand frames per second. He also has various optical 0:07:47.800 --> 0:07:50.680 and laser systems for visualizing the micro droplets that have 0:07:50.800 --> 0:07:53.600 created when we speak. So right now, as I've been talking, 0:07:53.680 --> 0:07:56.640 I've been emitting particles in the room right in front 0:07:56.680 --> 0:07:58.400 of me. And even though they're really tiny, too tiny 0:07:58.560 --> 0:08:01.680 to see, they're huge compared to the virus. So the 0:08:01.760 --> 0:08:04.440 virus can very happily be carried along in these micron 0:08:04.520 --> 0:08:07.080 skill So you have like a little little tiny bits 0:08:07.400 --> 0:08:09.920 of stunt, you know, basically floating around in the air 0:08:09.960 --> 0:08:14.119 that could be carrying the virus. The Bill's researchers showing 0:08:14.160 --> 0:08:17.680 that certain things can vary the emission of expertory particles. 0:08:18.480 --> 0:08:22.640 We found that speaking releases much more than breathing. And 0:08:22.800 --> 0:08:24.560 we went even further, and what we showed is that 0:08:24.720 --> 0:08:27.760 like how many particles emitted doing speech is a very 0:08:27.840 --> 0:08:30.480 strong function of how loud you are. So if you 0:08:30.520 --> 0:08:33.120 speak really loud, you emit a ton of way more 0:08:33.160 --> 0:08:34.800 than if you than if you required if you whisper. 0:08:35.520 --> 0:08:39.160 And some folks just emit a lot of particles. Bill says, 0:08:39.200 --> 0:08:43.520 some people are super emitters. So for whatever reason, um, 0:08:43.600 --> 0:08:46.120 some individuals when they talk just amit an order of 0:08:46.160 --> 0:08:50.240 magnitude more factor tend more than other people. And Bill 0:08:50.280 --> 0:08:53.520 says when some people cough for whatever reason, why more 0:08:53.640 --> 0:08:58.559 comes out. But these supermit is super spreaders of the coronavirus. 0:08:59.160 --> 0:09:02.559 That's a very challenge hypothesis to test post facto from 0:09:02.559 --> 0:09:07.800 an outbreak, but it's definitely a hypothesis that wants more investigation. 0:09:07.960 --> 0:09:09.840 If I was the virus in China affect as many people, 0:09:09.840 --> 0:09:12.120 I'd want to a super emitter who also was a 0:09:12.120 --> 0:09:15.000 super grower the virus, or like the virus was very successful, 0:09:15.080 --> 0:09:18.240 so you had a very high viral concentrations. And then 0:09:18.240 --> 0:09:19.640 I make sure if I was a virus again that 0:09:19.800 --> 0:09:23.040 I didn't make the person symptomatic, so they looked very healthy. 0:09:23.120 --> 0:09:25.160 And I'd have them go to a bar or a 0:09:25.240 --> 0:09:27.600 choir practice and have them sing and just vocalize as 0:09:27.640 --> 0:09:30.240 much as possible for a very long time. And I'd 0:09:30.240 --> 0:09:32.400 also tell the people to shut off the ventilation, uh 0:09:32.440 --> 0:09:35.240 so so that you know, to get the airborne viral 0:09:35.280 --> 0:09:38.040 concentration as high as possible. But also found that saying 0:09:38.080 --> 0:09:42.320 certain words it's associated with more particles admitted employs. It's 0:09:42.400 --> 0:09:46.480 like Papa produced more than fricatives like fafa but in 0:09:46.520 --> 0:09:50.200 general it was less important. Again if I was if 0:09:50.240 --> 0:09:51.839 I was a virus, I wouldn't care so much about 0:09:51.960 --> 0:09:54.920 what the word you're saying is. I would want to 0:09:54.920 --> 0:09:57.480 be in somebody who's saying it loudly. Right, So, in 0:09:57.520 --> 0:10:01.600 other words, minor changes and how loud you're articulating swamp 0:10:01.640 --> 0:10:04.960 out of the differences and what you're articulating. Does this 0:10:05.000 --> 0:10:08.760 mean people should be quiet for the sake of public health. 0:10:09.600 --> 0:10:12.080 I was advocating to some journalists who interviewed me back 0:10:12.120 --> 0:10:14.920 in April, and I said, I think we should start 0:10:14.960 --> 0:10:19.040 thinking about recommending people don't talk so much, especially in 0:10:19.120 --> 0:10:21.360 high risk of rooms like hospital wedding rooms. Back then, 0:10:21.400 --> 0:10:23.280 the report is looking at like that's crazy, but I 0:10:23.320 --> 0:10:26.920 think I think there is great to that. Now in September, 0:10:27.120 --> 0:10:30.560 that recommendation is sounding kind of sensible. We know that 0:10:30.640 --> 0:10:34.240 maintaining a physical distance, wearing a face mask, and thorough 0:10:34.320 --> 0:10:37.760 handwashing all helped to reduce the risk of spreading the coronavirus, 0:10:38.120 --> 0:10:41.120 but none is fail safe. It's doing them all together 0:10:41.720 --> 0:10:45.400 and quietly and offers the best chance at driving the 0:10:45.400 --> 0:11:06.400 pandemic into submission. That was Jason Gail, And that's it 0:11:06.480 --> 0:11:08.920 for our show Today. For coverage of the outbreak from 0:11:08.920 --> 0:11:12.199 one D and twenty bureaus around the world, visit bloomberg 0:11:12.320 --> 0:11:16.360 dot com Flash Coronavirus and if you like the show, 0:11:16.720 --> 0:11:19.640 please leave us a review and a rating on Apple 0:11:19.720 --> 0:11:23.320 Podcasts or Spotify. It's the best way to help more 0:11:23.360 --> 0:11:27.760 listeners find our global reporting. The Prognosis Daily edition is 0:11:27.800 --> 0:11:32.520 produced by topor foreheads Jordan gas Pure, Magnus Hendrickson, and 0:11:32.640 --> 0:11:37.280 me Laura Carlson. Today's main story was reported by Jason Gale. 0:11:37.800 --> 0:11:42.120 Original music by Leo Sidrin. Our editors are Rick Shine 0:11:42.120 --> 0:11:46.960 and Francesca Levi. Francesca Levi is Bloomberg's head of podcasts. 0:11:47.440 --> 0:11:48.319 Thanks for listening.