WEBVTT - Coronavirus Disease 2019 (COVID-19) 0:00:03.040 --> 0:00:05.360 Welcome to stot to Blow Your Mind production of My 0:00:05.480 --> 0:00:14.160 Heart Radio. Hey are you welcome to Stuff to Blow 0:00:14.200 --> 0:00:17.120 Your Mind? My name is Robert Lamb and I'm Joe McCormick. 0:00:17.160 --> 0:00:18.919 And today on Stuff to Blow Your Mind, we're gonna 0:00:18.920 --> 0:00:21.280 be doing something a little bit different than we usually do. 0:00:21.360 --> 0:00:25.080 We are going to be talking about an ongoing global 0:00:25.640 --> 0:00:28.800 disease outbreak. So if you've listened to us for a while, 0:00:29.360 --> 0:00:31.400 you know that while science is the heart of the show, 0:00:31.440 --> 0:00:34.640 we you know, we rarely cover breaking science news. It's 0:00:34.680 --> 0:00:36.879 not really our wheelhouse. They have been well maybe one 0:00:36.960 --> 0:00:38.840 or two times when we've kind of dipped our toe 0:00:38.880 --> 0:00:41.479 into that. And a part of the deal with breaking 0:00:41.520 --> 0:00:45.519 science is that sometimes it it breaks you back when 0:00:45.520 --> 0:00:48.080 you realize, oh, well, that's study about tartar grades had 0:00:48.080 --> 0:00:50.479 some it's had some problems with it. Remember that's like 0:00:50.479 --> 0:00:53.519 we're recording another episode on tartar grades the following week. Yep. 0:00:53.960 --> 0:00:56.040 Uh so yeah. Obviously, while we like to give the 0:00:56.080 --> 0:00:58.440 most up to date information we can whenever we dive 0:00:58.440 --> 0:01:00.600 into a subject, it's actually pretty rare that we cover 0:01:00.640 --> 0:01:04.200 a science story because it's the subject of current headlines 0:01:04.240 --> 0:01:05.760 and there are a few reasons for this. You know, 0:01:05.840 --> 0:01:07.600 we like to go deep a lot of times when 0:01:07.600 --> 0:01:10.280 news about a discovery first breaks there isn't a lot 0:01:10.280 --> 0:01:13.479 of depth yet to explore. But also the early days 0:01:13.480 --> 0:01:16.800 of a scientific news story are often full of rapid 0:01:16.880 --> 0:01:20.160 revisions and leads that turn out to be false or misguided. 0:01:20.520 --> 0:01:22.240 Those can be easier to fix, I think in a 0:01:22.280 --> 0:01:24.759 printed article, where you can simply go in and make 0:01:24.880 --> 0:01:27.640 edits or corrections or links to updates. That kind of 0:01:27.640 --> 0:01:30.520 thing doesn't work very well for recorded audio. So we 0:01:30.600 --> 0:01:32.640 do our best to cover subjects that we think we 0:01:32.680 --> 0:01:35.240 can get right the first time, go deep on and 0:01:35.400 --> 0:01:38.160 cover in a kind of evergreen way. Um, but right 0:01:38.200 --> 0:01:41.040 now there is a still developing global health story that 0:01:41.080 --> 0:01:43.400 we figured it was really important to address on our show, 0:01:43.840 --> 0:01:47.520 and that's the at this point, very likely global pandemic 0:01:47.680 --> 0:01:51.720 of coronavirus. So given the subject of today's story, we 0:01:51.760 --> 0:01:54.160 really need to be even more clear than usual about 0:01:54.240 --> 0:01:58.800 when we're researching, recording, and the publishing this episode. It 0:01:58.880 --> 0:02:04.560 was researched the last week of February, recorded on February, 0:02:04.960 --> 0:02:09.320 and it will be published on March three. Now we're 0:02:09.320 --> 0:02:11.160 gonna do what we can to make sure it's up 0:02:11.200 --> 0:02:14.480 to date at the point of publication, but certainly bear 0:02:14.520 --> 0:02:16.840 in mind that the story will continue to move in 0:02:16.880 --> 0:02:20.880 the days and weeks following its publication. So there's a 0:02:21.000 --> 0:02:23.639 lot of media coverage out there about this right now. 0:02:24.120 --> 0:02:26.440 Some of it is is great, some of it is 0:02:26.480 --> 0:02:29.880 perhaps a bit more on the panic side of the equation. 0:02:30.320 --> 0:02:33.359 UH studies are flying off the digital press. Government health 0:02:33.440 --> 0:02:36.880 organizations such as the CDC and UH that's the Centers 0:02:36.880 --> 0:02:40.320 for Disease Control and Prevention, and the World Health Organization 0:02:40.440 --> 0:02:42.440 or do we call them the who do you like 0:02:42.480 --> 0:02:44.440 to call them? The w h O? Or the who? 0:02:44.600 --> 0:02:48.600 I call them? The who? Are you? Well? They are 0:02:48.720 --> 0:02:51.400 essential voices in all of this, but in the in 0:02:51.440 --> 0:02:56.440 some cases governmental um responses and communications have been criticized, 0:02:56.680 --> 0:03:00.760 and there's also a fair amount of misinformation, races, xenophobia, 0:03:00.800 --> 0:03:02.680 and fear out there. So we're gonna do what we 0:03:02.720 --> 0:03:06.519 can to stick to the facts here and to give 0:03:06.600 --> 0:03:10.360 you a balanced view of the current state of the 0:03:10.400 --> 0:03:13.360 coronavirus and give you some tips about what you need 0:03:13.400 --> 0:03:17.000 to do to potentially prepare and to further educate yourself 0:03:17.040 --> 0:03:19.000 on the topic. Right, So, I guess we should start 0:03:19.040 --> 0:03:21.760 with a brief sketch of the timeline on this new 0:03:21.800 --> 0:03:25.040 disease up to the present. So how did the story begin. Well, 0:03:25.080 --> 0:03:27.720 at the end of last year. On December thirty one, 0:03:27.919 --> 0:03:31.440 twenty nineteen, the National China Office of the World Health 0:03:31.520 --> 0:03:34.920 Organization was notified of a localized surge in cases of 0:03:34.920 --> 0:03:38.920 pneumonia with an unknown origin in Wuhan's City, which is 0:03:38.920 --> 0:03:41.480 in the Hubei Province of China, and it's home to 0:03:41.520 --> 0:03:44.760 about eleven million people, So this is considered central China. 0:03:45.000 --> 0:03:46.960 And if you're if you're listening to this and you're 0:03:46.960 --> 0:03:49.400 trying to roughly picture it on a map, it's something 0:03:49.440 --> 0:03:52.880 like six hundred miles more or less directly north of Guangzhou, 0:03:53.360 --> 0:03:56.120 So we're talking about like an eleven hour bus drive 0:03:56.160 --> 0:03:59.480 according to Google. Yeah, now, these were cases of pneumonia 0:03:59.520 --> 0:04:01.520 at the time. That that's how they were recognized. And 0:04:01.520 --> 0:04:04.920 pneumonia just refers to a type of inflammation and the 0:04:04.960 --> 0:04:07.920 air sacks of the lungs, usually due to bacterial or 0:04:07.960 --> 0:04:10.600 viral infection. I guess there are multiple types of pathogens 0:04:10.640 --> 0:04:13.040 like fungus and other parasites can get in there too. 0:04:13.320 --> 0:04:15.960 Uh So pneumonia can have many causes. A common one 0:04:16.000 --> 0:04:19.880 would be the influence of virus or flu, except the 0:04:19.920 --> 0:04:22.599 patients presenting at the hospitals and Muhan did not have 0:04:22.760 --> 0:04:26.280 the flu. By January three, there were forty four cases 0:04:26.320 --> 0:04:30.159 of Wuhan city pneumonia with unknown ideology, meaning we don't 0:04:30.240 --> 0:04:35.080 understand what's causing it. But obviously a new, unidentified pathogen 0:04:35.240 --> 0:04:38.680 was suspected. So when a new and unfamiliar epidemic breaks out, 0:04:38.720 --> 0:04:42.240 what tools to epidemiologists have to try to understand things well? 0:04:42.360 --> 0:04:45.440 One is to look for underlying patterns among the people 0:04:45.560 --> 0:04:48.360 presenting with the novel infection. Is there anything many or 0:04:48.400 --> 0:04:51.120 all of them have in common, any place they've all been, 0:04:51.600 --> 0:04:54.760 any food they've all eaten, or anything like that? And 0:04:54.839 --> 0:04:58.359 this method quickly brought a likely ground zero for exposure 0:04:58.360 --> 0:05:02.080 into focus, which was a specific food market in Wuhan 0:05:02.440 --> 0:05:06.159 which in some cases sold live animals, including seafood, rabbits, 0:05:06.160 --> 0:05:09.840 and poultry. This was the juan On Seafood Wholesale Market, 0:05:10.200 --> 0:05:13.320 and several of the initial patients apparently worked there. The 0:05:13.320 --> 0:05:16.640 market was shut down on January one and subjected to 0:05:16.800 --> 0:05:20.800 sanitation protocols. Yeah, and again, despite its name, the market 0:05:20.880 --> 0:05:24.800 sees fairly varied trade and numerous animals, including several different 0:05:24.839 --> 0:05:28.680 varieties of mammals. So we call cases such as this 0:05:29.360 --> 0:05:35.000 zoonosis in which bacterium, virus or parasite transfers from an 0:05:35.080 --> 0:05:38.520 animal host to a human host, and there are numerous 0:05:38.560 --> 0:05:42.000 possible vectors and ways that it can spread. The reverse 0:05:42.080 --> 0:05:45.120 is also possible, by the way, either known as reverse 0:05:45.160 --> 0:05:50.600 zunosis or anthroponosis uh, in which one of these pathogens 0:05:50.680 --> 0:05:54.520 or virus or whatever basses from a human to an animal. Yeah, 0:05:54.520 --> 0:05:56.960 and very very often when there is a new disease, 0:05:57.040 --> 0:05:59.880 it's a case of zoonosis, right, and something is popped 0:06:00.040 --> 0:06:03.680 up because a disease formerly present in some species of 0:06:03.680 --> 0:06:07.360 animal has jumped and suddenly appeared in humans. Yeah, And 0:06:07.400 --> 0:06:09.359 then that's why it can be dangerous, because suddenly you 0:06:09.360 --> 0:06:12.080 have a new bacteria, virus, or parasite that the immune 0:06:12.080 --> 0:06:16.279 system and health experts are not specifically ready for or 0:06:16.400 --> 0:06:17.680 or you know, or you know, you haven't had a 0:06:17.720 --> 0:06:19.920 chance for an immunity to build up or for very 0:06:20.000 --> 0:06:23.080 targeted um uh, you know health strategy to be put 0:06:23.120 --> 0:06:25.680 in place. Yeah. Well, we're unprepared in multiple ways, right. 0:06:25.720 --> 0:06:28.800 We don't have effective treatments yet. Likely we don't have 0:06:28.839 --> 0:06:32.159 effective vaccines yet. Likely we don't know what to look 0:06:32.200 --> 0:06:34.680 for yet with this new disease, and people don't have 0:06:34.720 --> 0:06:36.880 a natural immunity to it, so it hits us in 0:06:36.960 --> 0:06:40.720 our unpreparedness in multiple ways all at once. So one 0:06:40.720 --> 0:06:42.800 thing we need to drive home with zoonosis is that 0:06:43.240 --> 0:06:46.479 it has always occurred, uh, you know, anywhere humans have 0:06:46.640 --> 0:06:50.080 been in close confines with animals. Uh, there is a 0:06:50.600 --> 0:06:54.200 there there is a possibility for for the pathogen to 0:06:54.200 --> 0:06:58.320 to to switch teams, to mute, to to jump over 0:06:58.360 --> 0:07:01.720 to a new host, and examples include everything from like 0:07:01.800 --> 0:07:05.120 rabies and bird flu to to HIV, with with HIV 0:07:05.200 --> 0:07:08.080 being an example of something that's subsequently mutated into a 0:07:08.160 --> 0:07:11.760 human only variety. Yeah, I believe the most recent consensus 0:07:11.800 --> 0:07:13.920 on that is that it was probably originally an immune 0:07:14.000 --> 0:07:16.960 virus affecting apes. Right, And and of course there are 0:07:17.080 --> 0:07:20.360 multiple ways for uh, for the for these this lead 0:07:20.400 --> 0:07:22.480 to take place. You can come from the eating of animals, 0:07:22.480 --> 0:07:25.440 from just you know, raising animals and being close proximity 0:07:25.480 --> 0:07:28.440 with them, pats or another area. And we'll get back 0:07:28.440 --> 0:07:30.320 to some of the details on that in a bit. Okay, So, 0:07:30.400 --> 0:07:34.040 what were the symptoms that were identified for this unknown 0:07:34.120 --> 0:07:37.080 type of pneumonia that was appearing in Wuhan City. Some 0:07:37.120 --> 0:07:41.120 of the early symptoms were fever, difficulty breathing, and X 0:07:41.240 --> 0:07:45.520 rays showing lesions in both lungs. There were initially fears 0:07:45.560 --> 0:07:48.560 that the virus was a resurgence of the Severe Acute 0:07:48.560 --> 0:07:52.560 Respiratory Syndrome or STARS uh an outbreak of viral infection 0:07:52.600 --> 0:07:55.160 that killed hundreds of people worldwide in two thousand two 0:07:55.240 --> 0:07:58.400 and two thousand three but was ultimately contained, and these 0:07:58.440 --> 0:08:02.360 suspicions of association with STARRS were close. They were close 0:08:02.400 --> 0:08:05.000 to the mark. On January seven, officials announced they had 0:08:05.080 --> 0:08:08.400 identified a novel viruses, the Culprit, which was at the 0:08:08.440 --> 0:08:11.360 time called twenty nineteen in c O V. It was 0:08:11.400 --> 0:08:15.960 a new strain of the coronavirus family, and coronaviruses are common. 0:08:16.120 --> 0:08:19.600 They account for all kinds of diseases, including STARS, but 0:08:19.720 --> 0:08:22.480 also instances of the Common Cold. Like the Common Cold, 0:08:22.600 --> 0:08:25.960 isn't caused by just one pathogen, but a range of 0:08:26.000 --> 0:08:30.360 similar viruses that affect the upper respiratory system. On January eleven, 0:08:30.520 --> 0:08:33.720 China announced the first death from this new disease. It 0:08:33.760 --> 0:08:35.560 was a sixty one year old man who had passed 0:08:35.559 --> 0:08:38.600 away two days earlier of heart failure stemming from the infection, 0:08:39.240 --> 0:08:42.439 and confirmed infections and deaths continued to spread in the 0:08:42.520 --> 0:08:45.600 following days. By the twenty second of January, at least 0:08:45.679 --> 0:08:48.160 seventeen people had died in China. There were more than 0:08:48.240 --> 0:08:51.560 five and fifty infections. Uh There were attempts to control 0:08:51.640 --> 0:08:54.640 the spread of the disease through travel restrictions and quarantines, 0:08:54.800 --> 0:08:57.960 but that they failed. Essentially they weren't able to contain it. 0:08:58.360 --> 0:09:02.240 On January, the World Health Organization announced that coronavirus was 0:09:02.280 --> 0:09:04.920 a global emergency. At this time, there had been a 0:09:05.000 --> 0:09:07.880 hundred and seventy deaths in China, with seven thousand, seven 0:09:07.960 --> 0:09:11.320 hundred and eleven cases reported in the country, where the 0:09:11.400 --> 0:09:14.280 virus had spread to all thirty one provinces by this time, 0:09:14.600 --> 0:09:17.000 and also by this time cases are popping up in 0:09:17.040 --> 0:09:20.160 other countries around the world uh AS one note on 0:09:20.240 --> 0:09:22.880 February seven, Lee Win Leong, who was one of the 0:09:22.920 --> 0:09:25.880 first doctors in China to raise concerns about the new virus, 0:09:26.000 --> 0:09:29.120 died on February eleventh. There were more than forty two 0:09:29.120 --> 0:09:31.960 thousand infections and more than a thousand deaths in China, 0:09:32.360 --> 0:09:34.880 and the World Health Organization at this point announced the 0:09:34.880 --> 0:09:38.000 new coronavirus had a name, it would be the coronavirus 0:09:38.040 --> 0:09:42.079 Disease twenty nineteen or COVID nineteen. In the weeks since, 0:09:42.120 --> 0:09:44.800 the global spread has continued and the number of infections 0:09:44.840 --> 0:09:47.480 and deaths has climbed, and on the day we're recording this, 0:09:47.640 --> 0:09:49.600 I was trying to get the most updated count I 0:09:49.600 --> 0:09:53.760 could uh. This morning, NBC News was reporting that coronavirus 0:09:53.800 --> 0:09:58.079 today has been confirmed in at least forty countries, including Italy, Iran, 0:09:58.280 --> 0:10:01.480 South Korea, and the United States. The most recent public 0:10:01.559 --> 0:10:04.720 numbers indicate that more than eighty thousand cases of infection 0:10:04.800 --> 0:10:08.720 have been confirmed and more than deaths, most of which 0:10:08.760 --> 0:10:11.360 have been in China. As far as the United States goes, 0:10:11.480 --> 0:10:15.880 the CDC has already announced it expects community transmission of 0:10:15.920 --> 0:10:19.800 COVID nineteen within the United States. And community transmission is 0:10:19.840 --> 0:10:23.880 an epidemiology term. It just means an infection is loose 0:10:23.960 --> 0:10:27.120 and spreading naturally within a population, So it's no longer 0:10:27.240 --> 0:10:30.120 that infections only appear in people who have traveled to 0:10:30.160 --> 0:10:34.040 places with known outbreaks. Community transmission just means it's here 0:10:34.080 --> 0:10:36.599 and it's spreading naturally among us. Yeah, it's kind of 0:10:36.600 --> 0:10:38.719 like the kinder egg. Used to the kinder egg with 0:10:38.840 --> 0:10:41.199 something that you know, you picked up on a vacation 0:10:41.440 --> 0:10:44.240 to another country and you brought back and then you shared. Uh. 0:10:44.400 --> 0:10:46.440 Now you can buy a form of the kinder egg 0:10:46.559 --> 0:10:49.160 all over the place. So you know, community transmission of 0:10:49.160 --> 0:10:51.880 the kinder egg is just a reality. Not that I'm 0:10:51.920 --> 0:10:55.800 I'm comparing the kinder egg to coronavirus, the kindred any 0:10:55.800 --> 0:10:59.440 other way significantly better than the Yes, definitely. So at 0:10:59.480 --> 0:11:01.720 the time of this recording, it appears that there is 0:11:01.760 --> 0:11:04.800 already at least one known case of community transmission in 0:11:04.800 --> 0:11:07.880 the United States in Sacramento, California. By the time this 0:11:07.920 --> 0:11:10.079 episode comes out, I would not be surprised if there 0:11:10.160 --> 0:11:13.920 are more that have been documented. Uh So, questions are 0:11:14.200 --> 0:11:17.320 how bad is this disease? How does it compare to 0:11:17.400 --> 0:11:21.200 other diseases were familiar with? There are two important numbers 0:11:21.240 --> 0:11:23.320 to understand when we're talking about the impact of a 0:11:23.360 --> 0:11:28.319 novel pathogen. One is the reproduction number, also known as 0:11:28.480 --> 0:11:31.520 are not which is spelled like R zero. I think 0:11:31.559 --> 0:11:34.200 that's not from how the British would what would call 0:11:34.320 --> 0:11:37.599 the zero and then the other is the case fatality 0:11:37.679 --> 0:11:41.440 rate and the reproduction number are not tells you for 0:11:41.520 --> 0:11:44.920 every one person who becomes infected, how many more people 0:11:44.960 --> 0:11:48.480 are likely to are they likely to spread the infection to. 0:11:49.280 --> 0:11:51.920 The case fatality rate is what percent of the people 0:11:51.920 --> 0:11:55.120 who contracts the disease die from it. So, for example, 0:11:55.600 --> 0:11:59.760 measles is a particularly nasty infection because of how easily 0:11:59.800 --> 0:12:02.920 it's spreads in the current world with an R are 0:12:02.960 --> 0:12:07.360 not somewhere between twelve and eighteen. So in the world today, 0:12:07.400 --> 0:12:10.120 if you if you get measles on average, you're potentially 0:12:10.120 --> 0:12:12.559 going to spread it to like fifteen other people, the 0:12:12.760 --> 0:12:16.040 one reason the measles vaccine is so important. A reproduction 0:12:16.080 --> 0:12:19.800 number greater than one indicates the diseases spreading, right because 0:12:19.800 --> 0:12:22.160 it's being you know, it's infecting more people than are 0:12:22.200 --> 0:12:26.200 currently infected. A reproduction number of less than one usually 0:12:26.200 --> 0:12:29.360 indicates that an infection is dying out. I was reading 0:12:29.360 --> 0:12:31.720 a piece by ed Young in The Atlantic. However, that 0:12:31.760 --> 0:12:35.720 pointed out some difficulties with interpreting reproduction numbers for for 0:12:35.760 --> 0:12:40.640 emerging diseases. For example, the reproduction number is an average, right, 0:12:40.679 --> 0:12:44.319 so a disease that has a reproduction number of two 0:12:44.920 --> 0:12:48.280 could mean that every single person who gets infected spreads 0:12:48.320 --> 0:12:51.320 the pathogen to two new people. Or it could mean 0:12:51.360 --> 0:12:54.280 that one person out of fifty spreads the disease to 0:12:54.360 --> 0:12:57.320 a hundred people, and this this actually has been known 0:12:57.360 --> 0:13:00.760 to happen. These cases can become known as super spreaders, 0:13:01.120 --> 0:13:06.840 cases where certain diseases are spread uh disproportionately by select 0:13:06.920 --> 0:13:12.360 individuals uh And perhaps counterintuitively, diseases that propagate via superspreaders 0:13:12.440 --> 0:13:16.160 can be easier to contain than diseases that spread steadily 0:13:16.200 --> 0:13:19.240 from person to person across all cases. I guess that 0:13:19.360 --> 0:13:23.040 the easy go to example of this is it's typhoid Mary, right, 0:13:23.120 --> 0:13:26.200 Mary Mallan? Yeah? Who as she wasn't the only superspreader 0:13:26.200 --> 0:13:29.320 of typhoid or typhoid fever, I guess yeah, But she 0:13:29.440 --> 0:13:32.160 was somebody who worked in food service and food preparation 0:13:32.840 --> 0:13:38.160 and uh and while not showing strong symptoms of infection, 0:13:38.240 --> 0:13:42.920 herself kept spreading the typhoid to other people. If memory serves, 0:13:42.960 --> 0:13:44.959 there's an episode of the Nick that deals with her. 0:13:46.480 --> 0:13:50.280 Now are there cases of superspreaders of coronavirus. It's still early, 0:13:50.400 --> 0:13:53.480 but it seems so I was finding several examples in 0:13:53.520 --> 0:13:57.040 news reports. For example, one report in The Guardian from 0:13:57.120 --> 0:14:00.319 yesterday but in an article by Sarah Bosley and Martin 0:14:00.440 --> 0:14:05.360 Bellum alleging quote. The third British case of coronavirus was 0:14:05.400 --> 0:14:08.600 a man in his fifties who contracted the coronavirus infection 0:14:08.640 --> 0:14:11.880 at a conference in Singapore. He then traveled to France, 0:14:11.920 --> 0:14:14.200 where he stayed with his family in a ski chalet 0:14:14.280 --> 0:14:18.440 at the alpine resort La Contamin Montjoy. Five people who 0:14:18.440 --> 0:14:20.600 were in the chalet, including a boy of nine, if 0:14:20.600 --> 0:14:23.640 tested positive for coronavirus. Since the man came back to 0:14:23.680 --> 0:14:27.280 the UK on an easy Jet flight and was diagnosed 0:14:27.280 --> 0:14:30.080 in Brighton, another Briton who was on holiday in the 0:14:30.160 --> 0:14:33.120 chalet flew back to his home in Malorca and was 0:14:33.160 --> 0:14:36.760 admitted to hospital in Palma. The chief medical officer said 0:14:36.800 --> 0:14:39.880 four more people attested positive in England, all of whom 0:14:39.920 --> 0:14:43.160 were also on the skiing holiday in France. So it 0:14:43.200 --> 0:14:46.040 seems like there was a there was a massive transmission 0:14:46.080 --> 0:14:49.240 from this one person who contracted it. I was also 0:14:49.320 --> 0:14:51.680 reading a report of a woman in South Korea who 0:14:51.760 --> 0:14:54.920 is at this point believed to have so far spread 0:14:55.000 --> 0:14:59.160 the coronavirus to at least thirty seven people at her church. Yes, 0:14:59.160 --> 0:15:00.960 I think I was reading about part part of this 0:15:01.040 --> 0:15:04.880 deals with like this particular church. You know, they their congregation, 0:15:04.960 --> 0:15:07.600 how they gather and then how they go out and 0:15:07.920 --> 0:15:10.960 uh an attempt to spread the word, right, But it 0:15:11.040 --> 0:15:14.040 could also have to do with just specifics of of 0:15:14.160 --> 0:15:17.600 individual variation in in you know, how how your immune 0:15:17.640 --> 0:15:20.400 system works. Like there appears to be something called a 0:15:20.520 --> 0:15:24.239 twenty eight rule for the spread of many infectious diseases 0:15:24.600 --> 0:15:26.480 uh to quote from a two thousand eleven paper by 0:15:26.600 --> 0:15:29.880 Richard A. Stein and the International Journal of Infectious Diseases. 0:15:30.000 --> 0:15:33.960 Quote in what became known as the rule, a concept 0:15:34.040 --> 0:15:38.479 documented by observational and modeling studies and having profound implications 0:15:38.480 --> 0:15:42.560 for infection control, twenty percent of the individuals within any 0:15:42.600 --> 0:15:46.440 given population are thought to contribute at least eighty percent 0:15:46.560 --> 0:15:50.520 to the transmission potential of a pathogen, and many host 0:15:50.560 --> 0:15:54.400 pathogen interactions were found to follow this empirical rule. Now, 0:15:54.760 --> 0:15:57.280 this isn't true of every disease, but what they're saying 0:15:57.360 --> 0:16:00.400 is it's it's been discovered that for many disease eases 0:16:00.480 --> 0:16:04.440 that are infectious and spread from person to person, of 0:16:04.480 --> 0:16:08.200 the people infected do eighty percent of the spreading. Now, 0:16:08.240 --> 0:16:10.720 I think it's it's important, of course, not to demonize 0:16:10.760 --> 0:16:13.880 people who happen to be super spreaders. They're almost never 0:16:13.920 --> 0:16:17.160 spreading a disease on purpose. Uh. The factors that make 0:16:17.240 --> 0:16:19.960 somebody a super spreader still not fully understood, but it 0:16:20.000 --> 0:16:22.440 may just have something to do with how their immune 0:16:22.440 --> 0:16:26.160 system works. Uh. Sometimes it happens because a disease that 0:16:26.240 --> 0:16:30.360 makes other people very obviously outwardly sick creates almost no 0:16:30.480 --> 0:16:32.960 symptoms and the super spreader so they don't even know 0:16:33.000 --> 0:16:35.160 they're spreading it to people. Right, And I believe this 0:16:35.200 --> 0:16:38.360 was the case with typhoid Mary for example. Right. So yeah, 0:16:38.440 --> 0:16:42.440 again it's important not to demonize that in any way. Well, actually, 0:16:42.480 --> 0:16:44.720 I think with typhoid Mary, I'm not saying we should 0:16:44.760 --> 0:16:47.040 demonize her either, but I think at some point she 0:16:47.200 --> 0:16:50.400 was made aware but then had after that, at least 0:16:50.440 --> 0:16:53.200 for a while, continued to work in food service. So obviously, 0:16:53.200 --> 0:16:55.520 if you were aware that you are, you know that 0:16:55.520 --> 0:16:57.720 that you may have an infection that could spread to 0:16:57.720 --> 0:17:00.480 other people, you should do whatever possible not to spread 0:17:00.480 --> 0:17:03.440 it to people. And we can talk about practical methods 0:17:03.440 --> 0:17:05.960 for that in a bit here. But also coming back 0:17:06.000 --> 0:17:09.879 to the reproduction number of an infection, the reproduction number, 0:17:10.280 --> 0:17:12.600 and Young points out and actually several authors I was 0:17:12.600 --> 0:17:14.440 looking at have have made this point. It's a very 0:17:14.440 --> 0:17:18.040 good one. It is not a fully fixed biological feature 0:17:18.080 --> 0:17:21.879 intrinsic to the pathogen. The reproduction number of a pathogen 0:17:21.960 --> 0:17:25.719 can be influenced by human interventions. Young points out that 0:17:25.880 --> 0:17:31.000 stars originally had very different reproduction numbers in China and Canada, 0:17:31.080 --> 0:17:33.520 so you'd get are nots ranging from like two to 0:17:33.840 --> 0:17:36.840 five or six, and this was just because of different 0:17:36.920 --> 0:17:40.760 levels of success in diagnosing and containing the cases that appeared. 0:17:41.400 --> 0:17:44.760 Coronavirus is no different. It's are not is influenced by 0:17:44.800 --> 0:17:48.880 biological facts about the virus itself, but also about how 0:17:48.880 --> 0:17:51.399 well people respond to it, what kinds of measures we 0:17:51.440 --> 0:17:54.760 can put in place, uh to contain it and stop transmission. 0:17:54.760 --> 0:17:56.840 And we'll get to those numbers in a second. But 0:17:56.920 --> 0:18:00.680 also I mentioned there's there's the the inner action between 0:18:00.760 --> 0:18:04.120 the reproduction number and the case fatality rate of an 0:18:04.119 --> 0:18:08.040 emerging pathogen. So meanwhile, UH, the hemorrhagic fever I bola 0:18:08.200 --> 0:18:11.280 does not spread super easily between people. It usually has 0:18:11.280 --> 0:18:14.720 an are not between one and two. It's not highly 0:18:14.800 --> 0:18:18.359 highly infectious, but I bola is very scary because it 0:18:18.440 --> 0:18:21.879 has such a high case fatality rate some somewhere around 0:18:21.880 --> 0:18:24.159 fifty percent of the people who get a bola end 0:18:24.240 --> 0:18:26.960 up dying from it, and there are diseases with even 0:18:27.040 --> 0:18:30.960 higher CFRs. Avian influenza A or H five in one 0:18:31.440 --> 0:18:35.440 has a CFR somewhere around sixty percent. Coronavirus is nowhere 0:18:35.520 --> 0:18:37.920 near that high, and in fact, depending on how you 0:18:38.000 --> 0:18:41.000 measure it, there are greater dangers represented by much more 0:18:41.040 --> 0:18:45.000 familiar diseases like seasonal flu. Like seasonal flu has a 0:18:45.080 --> 0:18:49.880 lower case fatality rate than coronavirus appears to. Seasonal flu 0:18:50.000 --> 0:18:53.480 has something like an average rate of point zero one 0:18:53.560 --> 0:18:56.800 percent in the United States at least. However, it's still 0:18:56.920 --> 0:18:59.680 very dangerous just because of the number of people who 0:18:59.680 --> 0:19:02.960 get infected that this season alone, the flu has already 0:19:02.960 --> 0:19:07.600 caused more than twenty five million infections and fourteen thousand 0:19:07.640 --> 0:19:11.120 deaths in the United States alone. The flu usually has 0:19:11.160 --> 0:19:13.960 a reproduction number of something like one point three, and 0:19:14.000 --> 0:19:17.400 it comes in fairly predictable seasonal cycles, so we've kind 0:19:17.400 --> 0:19:19.400 of gotten used to it. Even though it is still 0:19:19.480 --> 0:19:22.359 a great I mean, it kills thousands every year, but 0:19:22.640 --> 0:19:25.320 I guess it seems less scary to us just because 0:19:25.480 --> 0:19:27.960 it's been around. We we sort of know what to 0:19:28.000 --> 0:19:31.320 look for now. So as for the specific reproduction number 0:19:31.320 --> 0:19:34.720 in case fatality rate of the new coronavirus, at one point, 0:19:34.720 --> 0:19:38.000 the World Health Organization estimated that its reproduction number was 0:19:38.040 --> 0:19:41.639 between about one point four and two point five. I 0:19:41.680 --> 0:19:44.560 was reading a recent study from the journal Travel Medicine 0:19:44.600 --> 0:19:47.840 which reviewed studies from between January one of this year 0:19:48.280 --> 0:19:50.720 and the seventh of February this year, and for this 0:19:50.800 --> 0:19:54.320 time period the author's right quote, we identified twelve studies 0:19:54.320 --> 0:19:57.680 which estimated the basic reproductive number for the COVID nineteen 0:19:57.800 --> 0:20:01.160 from China and overseas UH. The estimates range from one 0:20:01.200 --> 0:20:04.080 point four to six point four nine, with a mean 0:20:04.280 --> 0:20:06.800 of three point to eight, a median of two point 0:20:06.840 --> 0:20:10.399 seven nine, and interquartile range of one point one six. 0:20:10.760 --> 0:20:14.040 So maybe the range is by our best estimates now 0:20:14.119 --> 0:20:18.440 currently averaging between like two point five and three point five. 0:20:18.480 --> 0:20:22.280 I've also seen estimates between two and three, though, again 0:20:22.320 --> 0:20:25.240 to drive home, those numbers could change a lot depending 0:20:25.240 --> 0:20:28.919 on what kinds of new UH new diagnostic methods and 0:20:28.960 --> 0:20:33.280 containment methods come online. Reproduction numbers for a new emergent 0:20:33.400 --> 0:20:35.520 virus I think are going to tend to be higher 0:20:35.520 --> 0:20:38.240 than they are for something that we're better at looking for, 0:20:38.400 --> 0:20:41.399 because it takes us longer to recognize it and and 0:20:41.480 --> 0:20:45.320 stop it spread. As for the case fatality rate, overall, 0:20:45.480 --> 0:20:49.160 it appears to be somewhere around two percent on average, 0:20:49.160 --> 0:20:51.879 but it also varies greatly based on factors like the 0:20:51.920 --> 0:20:55.000 age of the infected person and perhaps other factors that 0:20:55.040 --> 0:20:58.159 haven't come into focus yet. One relieving thing about it 0:20:58.200 --> 0:21:00.760 is that the disease, at least so for appears to 0:21:00.800 --> 0:21:05.120 be pretty mild rate bordering on non existent in children. 0:21:05.240 --> 0:21:07.720 Children rarely seem to get it, and when they do, 0:21:07.920 --> 0:21:10.520 it's usually not severe and they don't die from it. 0:21:10.920 --> 0:21:13.879 Elderly populations, on the other hand, or people with compromised 0:21:13.920 --> 0:21:17.200 immune systems or other pre existing diseases, are at much 0:21:17.280 --> 0:21:19.760 higher risk. With the case fatality rate that could reach 0:21:19.800 --> 0:21:22.399 in some cases up to about fifteen percent, which is 0:21:22.440 --> 0:21:24.280 a lot. So at this point we shoul probably getto 0:21:24.320 --> 0:21:26.440 the symptoms a bit. You know, what are the symptoms 0:21:26.440 --> 0:21:29.560 as we understand them so far? For coronavirus. Right. So 0:21:29.600 --> 0:21:32.000 there are a lot of complications because the disease is 0:21:32.080 --> 0:21:33.920 so new, and we also don't yet have a good 0:21:33.920 --> 0:21:37.560 sense of how many people can become infected without showing 0:21:37.640 --> 0:21:40.200 major symptoms. It appears that at least some people are 0:21:40.359 --> 0:21:44.520 getting this virus without major symptoms, which is actually you 0:21:44.600 --> 0:21:47.080 might think, oh, that sounds good, but that's actually very bad. 0:21:47.440 --> 0:21:50.280 That can help it spread because some of these others, 0:21:50.520 --> 0:21:54.159