WEBVTT - New Ways to Catch the Virus 0:00:05.480 --> 0:00:10.560 Welcome to Prognosis. I'm Laura Carlson. It's day one and 0:00:10.600 --> 0:00:15.440 twenty four since coronavirus was declared a global pandemic. Today's 0:00:15.480 --> 0:00:19.200 main story. Much of what we know suggests the virus 0:00:19.320 --> 0:00:24.440 is transmitted through tiny droplets from infected people, but researchers 0:00:24.480 --> 0:00:28.200 are now looking at tiny air assaults that linger in 0:00:28.240 --> 0:00:34.320 the air and whether they too can infect us. But first, 0:00:35.320 --> 0:00:45.360 here's what happened in virus news today. The World Health 0:00:45.479 --> 0:00:48.520 Organization had a sobering message at a briefing this morning. 0:00:49.360 --> 0:00:54.600 COVID nineteen won't disappear quickly, and it's unrealistic to hang 0:00:54.640 --> 0:01:00.360 our hopes on a perfect vaccine emerging soon. You h 0:01:00.400 --> 0:01:04.240 Joe head tatris at Anam Gabrie Sus said strong government 0:01:04.319 --> 0:01:08.240 leadership was necessary and that fighting the virus is a 0:01:08.360 --> 0:01:13.520 long term commitment. In the US, the virus is making 0:01:13.520 --> 0:01:17.680 a comeback in states that thought they had already endured 0:01:17.920 --> 0:01:23.320 the worst of it. California, Louisiana, Michigan, and Washington State 0:01:23.600 --> 0:01:27.600 are seeing case counts climb again after months of declines. 0:01:28.560 --> 0:01:32.720 It's not just a matter of more testing, hospitalizations, and 0:01:32.760 --> 0:01:38.200 in some places, deaths are rising too. Experts say the 0:01:38.240 --> 0:01:40.800 diseases on the rise in these states for the same 0:01:40.880 --> 0:01:45.120 reasons it's breaking records in places like Florida. Those reasons 0:01:45.160 --> 0:01:49.360 include a population no longer willing to stay inside, Republicans 0:01:49.360 --> 0:01:53.600 who refuse face masks as a political statement, street protests 0:01:53.680 --> 0:01:58.080 over police violence, and young people convinced the virus won't 0:01:58.280 --> 0:02:03.680 seriously hurt them. Early in the pandemic, New York had 0:02:03.760 --> 0:02:06.600 one of the worst outbreaks in the US and took 0:02:06.640 --> 0:02:11.320 some of the strictest lockdown measures that has paid off. 0:02:11.919 --> 0:02:15.560 This weekend, New York City had its first day without 0:02:15.560 --> 0:02:19.840 a COVID nineteen death since the outbreak, But even there, 0:02:20.280 --> 0:02:24.960 officials are seeing a worrying trend. Cases are rising among 0:02:25.080 --> 0:02:30.160 people aged twenty nine. Today, Mayor build A Blasio said 0:02:30.320 --> 0:02:33.040 the city will work to educate young people on the 0:02:33.080 --> 0:02:42.400 importance of wearing masks and keeping socially distant. And now 0:02:42.520 --> 0:02:48.040 for today's main story, we're learning more about how stars 0:02:48.160 --> 0:02:52.160 cove two, the virus that causes COVID nineteen, is spread 0:02:52.200 --> 0:02:56.040 from person to person. For the most part, it happens 0:02:56.160 --> 0:02:59.600 when we're in close contact with an infected person who 0:02:59.680 --> 0:03:05.120 we met. Tiny liquid particles by coughing, sneezing, speaking, or singing. 0:03:06.040 --> 0:03:09.240 These droplets come out even when we just breathe. Normally, 0:03:10.520 --> 0:03:14.200 you get the virus by inhaling the droplets, having them 0:03:14.200 --> 0:03:17.560 travel into your ears or nose, or getting one stock 0:03:17.600 --> 0:03:21.960 on your hand which you then absentmindedly used to touch 0:03:22.000 --> 0:03:26.480 in orifice. But at a New Year's lunch in China, 0:03:26.919 --> 0:03:29.320 a group of people got sick in a way that 0:03:29.480 --> 0:03:33.959 suggested there might be another way you can get COVID nineteen, 0:03:34.800 --> 0:03:39.760 Bloomberg Senior editor Jason Gale reports on the latest worry 0:03:40.360 --> 0:03:45.520 that virus laden aerosols floating in gas clouds could infect us. 0:03:53.680 --> 0:03:58.960 In China, the holidays main mass migration. People travel across 0:03:59.000 --> 0:04:02.920 the country to catch up with relatives, enjoy reunion dinners, 0:04:03.080 --> 0:04:06.840 and hand out cash filled red envelopes to children. A 0:04:06.880 --> 0:04:10.800 family from Wuhan, the central Chinese city where the coronavirus emerged, 0:04:11.280 --> 0:04:14.480 was part of that mass movement. Back in January. This 0:04:14.560 --> 0:04:16.880 family of ten quarter train to the southern city of 0:04:16.920 --> 0:04:20.839 Guangzho the day before, having lunch in a crowded restaurant. 0:04:21.440 --> 0:04:24.359 It was the eve of the lunar New Year. What 0:04:24.440 --> 0:04:27.040 they didn't know at the time was that one of them, 0:04:27.279 --> 0:04:31.200 six year old art, was coming down with COVID nineteen. 0:04:32.000 --> 0:04:35.480 A few hours after leaving the restaurant, the retiree developed 0:04:35.480 --> 0:04:39.000 a fever and cough. It means she was probably at 0:04:39.000 --> 0:04:41.840 her most infectious when she squeezed into a seat at 0:04:41.839 --> 0:04:47.760 a round table at the back of the restaurant as 0:04:47.760 --> 0:04:50.599 the family enjoyed lunch and air conditioner blue air across 0:04:50.600 --> 0:04:52.839 the back of the room where they were seated. That 0:04:53.000 --> 0:04:57.520 was a few feet from two other families at neighboring tables. Importantly, 0:04:57.920 --> 0:05:00.400 their air conditioning unit on the wall facing the aren't 0:05:00.400 --> 0:05:04.880 incubating COVID was blowing air over all three tables, and 0:05:05.000 --> 0:05:08.520 it turns out that warm breeze and lunch were the 0:05:08.560 --> 0:05:11.760 only things these families shared. A week and a half later, 0:05:11.839 --> 0:05:15.240 on February five, nine more of the diners had come 0:05:15.240 --> 0:05:18.520 down with COVID nineteen, four members of the Wuhan family 0:05:18.839 --> 0:05:22.200 plus five members of the two other families, but none 0:05:22.200 --> 0:05:24.520 of the waiters or seventy three other patrons in the 0:05:24.560 --> 0:05:28.000 room contracted the disease, and neither did anyone back at 0:05:28.040 --> 0:05:37.040 the Guangzho Hotel. Whether the Wuhan family was staying researchers 0:05:37.200 --> 0:05:40.600 investigating the outbreak were in luck. There was a close 0:05:40.640 --> 0:05:44.320 circuit television camera in the restaurant, and the footage showed 0:05:44.400 --> 0:05:48.120 no close contact between each table's guests, aside from several 0:05:48.160 --> 0:05:51.240 seats being back to back. So to figure out how 0:05:51.279 --> 0:05:55.320 the virus spread over several meters, the researchers simulated the 0:05:55.360 --> 0:05:58.960 air flow across the three tables, and it pointed to 0:05:58.960 --> 0:06:02.640 what many scientists had feared. That is that the virus 0:06:02.760 --> 0:06:05.520 could be suspended and moved about in the ambient air 0:06:06.120 --> 0:06:10.400 long enough and far enough to cause multiple infections. That 0:06:10.520 --> 0:06:14.120 this could occur is no surprise for Professor Ben Cowling, 0:06:14.560 --> 0:06:17.920 head of epidemiology and bios Statistics at the University of 0:06:17.960 --> 0:06:20.720 Hong Kong, then assisted China in the early study of 0:06:20.760 --> 0:06:24.919 the coronavirus. Is transmission dynamics. When I hear that transmissions 0:06:24.960 --> 0:06:27.640 going on after prolong closed contact, it makes me think 0:06:27.720 --> 0:06:30.800 that aerosols are playing a role mostly at short range, 0:06:31.200 --> 0:06:34.320 but in rooms where there's poorer ventilation, people spend a 0:06:34.320 --> 0:06:36.279 longer period of time. You might see a little bit 0:06:36.320 --> 0:06:38.600 a long way to transmission. And we have seen outbreaks 0:06:38.600 --> 0:06:44.120 in coll centers. Enquired practices in restaurants and bars and nightclubs, 0:06:44.160 --> 0:06:46.160 and that's the kind of situations where where if their 0:06:46.200 --> 0:06:48.440 ventilation is not as good, you could see a bit 0:06:48.440 --> 0:06:52.520 of aerosols happening. The outbreak in the Guangho restaurant has 0:06:52.560 --> 0:06:55.599 become the touchstone in a global debate about how the 0:06:55.600 --> 0:06:59.880 coronavirus can spread in poorly ventilated spaces and the x 0:07:00.000 --> 0:07:03.000 your measures that may be required to halt it. At 0:07:03.000 --> 0:07:06.520 the heart of the controversy remained lingering questions about how 0:07:06.560 --> 0:07:11.360 often such airborne transmission occurs. After all, the gang incident 0:07:11.440 --> 0:07:14.560 shows a majority of diners in the restaurant remained healthy, 0:07:14.640 --> 0:07:17.120 and so did roughly half of the people at the 0:07:17.120 --> 0:07:20.240 table where the infected woman from Woohan was sitting, and 0:07:20.400 --> 0:07:23.720 at the tables on either side of hers. He's been 0:07:23.800 --> 0:07:27.320 calling again. Yes, So in Hong Kong, we've we've done 0:07:27.320 --> 0:07:29.840 a bit of that analysis. We've found that seventy of 0:07:29.840 --> 0:07:32.800 copy cases didn't pass infection to anyone else, and it 0:07:32.960 --> 0:07:36.600 was just a minority. It was a minority that caused 0:07:37.480 --> 0:07:41.239 on was transmission, and that's presumably a minority of cases 0:07:41.240 --> 0:07:44.040 are more contagious, and then among those, some of them 0:07:44.120 --> 0:07:46.600 have the potential to spread to lots of others, and 0:07:46.680 --> 0:07:50.119 so we have this super spreading phenomenon. And I think 0:07:50.520 --> 0:07:52.760 when there is super spreading going on, the most likely 0:07:52.800 --> 0:07:56.480 explanation for that is also aerosoul transmission. But that's not 0:07:56.560 --> 0:07:59.440 to scare everybody. That's just to state that the fact 0:07:59.480 --> 0:08:02.400 that viruses can spread in this way and we need 0:08:02.440 --> 0:08:05.640 to be aware of that, and ventilation can be particularly important. 0:08:09.480 --> 0:08:12.720 The World Health Organization updated a scientific paper about the 0:08:12.720 --> 0:08:16.320 transmission of the Sasko V two virus on Thursday. It 0:08:16.440 --> 0:08:20.040 said it doesn't rule out the possibility of airborne transmission 0:08:20.360 --> 0:08:24.520 in crowded areas or indoor venues with poor ventilation. However, 0:08:24.640 --> 0:08:27.800 the Geneva Base Agency said more researchers needed because in 0:08:27.840 --> 0:08:31.480 such cases there may be alternative explanations as to how 0:08:31.520 --> 0:08:35.760 people got sick, such as respiratory droplets that fell onto surfaces. 0:08:36.480 --> 0:08:39.360 The w h O faces pressure from scientists led by 0:08:39.559 --> 0:08:43.880 Lydia Morawska, director of the International Laboratory for Equality and 0:08:43.920 --> 0:08:49.000 Health at Queensland University of Technology in Australia. Lydia argues 0:08:49.080 --> 0:08:52.440 that hamwashing and physical distancing alone aren't enough to stem 0:08:52.520 --> 0:08:59.160 infections because in the air and to research over the 0:08:59.160 --> 0:09:02.319 past three months found the presence of the spirals in 0:09:02.760 --> 0:09:08.200 the air and retrospectively that it incurreted people. Lydia and 0:09:08.240 --> 0:09:10.880 a colleague published an open letter in a medical journal 0:09:10.960 --> 0:09:13.520 last week calling on the w h O and other 0:09:13.559 --> 0:09:17.480 international groups to address the airborne transmission of COVID nineteen. 0:09:18.200 --> 0:09:21.400 The letter documented research that was backed by two d 0:09:21.559 --> 0:09:25.880 and thirty nine scientists. It asked officials to consider such 0:09:25.920 --> 0:09:31.240 precautions as increasing ventilation and avoiding recirculating potentially virus late 0:09:31.320 --> 0:09:34.480 and air, and buildings like hospitals and schools to avoid 0:09:34.800 --> 0:09:36.959 the kind of scenario played out in the restaurant in 0:09:36.960 --> 0:09:40.960 Guangzho in January. What's being debated isn't what happens when 0:09:40.960 --> 0:09:45.120 an infected person coughs or sneezes globes of virus laden liquid. 0:09:45.600 --> 0:09:49.000 That's a long established murder of infection. Rather, it's where 0:09:49.040 --> 0:09:53.600 the tiny particles known as microdroplets and aerosols stay afloat 0:09:53.720 --> 0:09:56.520 long enough to be inhaled and cause infection deeper in 0:09:56.559 --> 0:10:08.440 the lungs, and therefore what troll measures to use. Resolving 0:10:08.480 --> 0:10:12.679 these questions is becoming increasingly urgent as workplaces, schools, and 0:10:12.720 --> 0:10:16.959 colleges reopen in the United States, President Donald Trump has 0:10:17.080 --> 0:10:21.200 rejected school reopening guidelines that included increasing the circulation of 0:10:21.240 --> 0:10:25.400 outdoor air as too difficult. I spoke with Lydia in 0:10:25.480 --> 0:10:28.200 late June, a week before her letter came out to 0:10:28.280 --> 0:10:31.920 help clear up some questions I had. Um. I think 0:10:31.960 --> 0:10:36.600 people have kind of mistakenly thought that there are droplets 0:10:36.800 --> 0:10:39.520 and then there are aerosols, and that it's very sort 0:10:39.559 --> 0:10:43.440 of binary, when in fact, there's a whole gradient of 0:10:43.880 --> 0:10:47.720 size of these particulars that come out of one's respiratory tract. 0:10:48.720 --> 0:10:52.400 Can you talk about that, Well, there is a very 0:10:52.440 --> 0:10:56.920 big mess in in relation to the terminology, and it's 0:10:57.000 --> 0:11:01.840 often considered that this small part ticles emitted excribed by 0:11:01.880 --> 0:11:05.400 people are called aerosols and the pick are called droplets. 0:11:05.480 --> 0:11:09.439 It's nothing like this. Aerosols. The definition of aerosols are 0:11:09.720 --> 0:11:14.120 liquid and solid particles in the air. Now droplets are 0:11:14.160 --> 0:11:19.240 liquid particles, So basically droplets are liquid aerosols. So therefore 0:11:19.280 --> 0:11:22.040 we are not talking smaller be It has nothing to 0:11:22.040 --> 0:11:25.439 do with size. Our breath isn't usually visible, but when 0:11:25.480 --> 0:11:28.080 it's really cold, we can see it as puffs of stain. 0:11:28.679 --> 0:11:32.200 Lidia said it's a helpful visualization of how virus leading 0:11:32.280 --> 0:11:35.640 particles of varying sizes can be expelled from an infected 0:11:35.679 --> 0:11:40.199 person in a turbulent gas cloud. But are these virus 0:11:40.280 --> 0:11:44.400 leading aerosols infectious? This depends on the condition of the 0:11:44.720 --> 0:11:50.120 of the environment. Viruses of the skype are like cool 0:11:50.280 --> 0:11:56.959 air and drysh conditions, so if these are the conditions 0:11:56.960 --> 0:12:01.000 like in many office buildings, for example, this could be 0:12:01.080 --> 0:12:04.079 both conditions. If, on the other hand, we go outside 0:12:04.559 --> 0:12:08.360 where there is hot and in addition new we radiation, 0:12:08.559 --> 0:12:11.800 well within very short period of time, they will be deactivated, 0:12:12.920 --> 0:12:16.600 which suggests being outside is less risky for catching the 0:12:16.600 --> 0:12:20.679 coronavirus than being indoors well, very much so. But this 0:12:20.760 --> 0:12:24.040 is not the only aspect, since you'll be radiation. It 0:12:24.200 --> 0:12:28.840 is the very fast dilution outdoors, which is a well 0:12:29.120 --> 0:12:34.400 large reservoir. Dilution is very fast, so therefore the airborne 0:12:34.440 --> 0:12:39.840 transmission outdoors has very little chances to walk. Of course, 0:12:39.840 --> 0:12:42.439 there is still that contact if you are standing next 0:12:42.440 --> 0:12:45.280 to somebody for long time and this person's misses that 0:12:45.360 --> 0:12:48.040 you or something like this, that's the close contact. But 0:12:48.160 --> 0:12:51.920 otherwise in the airborne transmission it's much less likely to 0:12:51.920 --> 0:12:55.920 occur outdoors. In her letter last week, Lydia recommended high 0:12:55.960 --> 0:13:00.120 efficiency air filtration and jem sidle ultra violet lights they 0:13:00.200 --> 0:13:03.640 used to reduce the risk of airborne transmission. She also 0:13:03.760 --> 0:13:07.600 pointed to simpler protective measures like supplying clean out or 0:13:07.640 --> 0:13:12.800 air and avoiding overcrowding on public transport. Since siskov to emerge, 0:13:13.000 --> 0:13:16.120 Lydia's written or contributed to more than a dozen papers 0:13:16.160 --> 0:13:23.760 on the potential for the pandemics airborne spread. This makes 0:13:23.840 --> 0:13:27.920 me even sort of more on acced determined to get 0:13:28.000 --> 0:13:31.120 something done about this, because once this pandemic is over, 0:13:32.080 --> 0:13:36.200 probably won't happen dead quickly at once the pandemic is over. Again, 0:13:36.600 --> 0:13:40.040 this and this is not the issues are not recognized 0:13:40.400 --> 0:13:43.600 and not taking Carl and we are we were in 0:13:43.400 --> 0:13:48.240 the same situation during the next person. Evidence for airborne 0:13:48.240 --> 0:13:53.360 transmission of the coronavirus is still emerging and incomplete examples 0:13:53.400 --> 0:13:57.160 like the Gango restaurant suggests it's the most plausible explanation 0:13:57.559 --> 0:14:01.760 for how people were infected in some situations. While scientists 0:14:01.760 --> 0:14:05.880 conduct further research to better understand why, how, and to 0:14:05.960 --> 0:14:10.000 what extent these microscopic particles can spread, COVID nineteen. There 0:14:10.000 --> 0:14:13.520 are things we can do to mitigate that risk. Stay 0:14:13.559 --> 0:14:17.960 home if you're sick, coffin, sneeze into your elbow, observe 0:14:18.160 --> 0:14:23.800 physical distancing recommendations, avoid crowded, poorly ventilated indoor spaces, and 0:14:24.240 --> 0:14:38.320 where it's appropriate, where a face mask. That was Jason 0:14:38.400 --> 0:14:42.040 Gale in Melbourne. And that's it for our show. For 0:14:42.160 --> 0:14:45.000 coverage of the outbreak from one and twenty bureaus around 0:14:45.000 --> 0:14:50.000 the world, visit Bloomberg dot com slash coronavirus and if 0:14:50.040 --> 0:14:52.440 you like the show, please leave us a review and 0:14:52.520 --> 0:14:56.440 a rating on Apple Podcasts or Spotify. It's the best 0:14:56.440 --> 0:15:00.520 way to help more listeners find our global reporting. The 0:15:00.560 --> 0:15:05.040 Prognosis Daily edition is produced by Topher Foreheads Jordan Gaspore, 0:15:05.520 --> 0:15:10.640 Magnus Hendrickson and me Laura Carlson. Today's main story was 0:15:10.720 --> 0:15:15.840 reported by Jason Gale. Original music by Leo Sidran. Our 0:15:15.960 --> 0:15:20.480 editors are Rick Shine and Francesca Levi. Francesca Levie is 0:15:20.480 --> 0:15:23.720 Bloomberg's head of podcasts. Thanks for listening.