Today, Explained - How Covid-19 attacks your body

Episode Date: March 30, 2020

In this episode of Vox's Reset podcast Ed Yong from The Atlantic explains how a little spiky ball called SARS-CoV2 brought the world to its knees. (Transcript here.) Learn more about your ad choices. Visit podcastchoices.com/adchoices

It's Monday, March 30th, 2020, and the president is canceling his Easter plans. I'm Sean Ramos for him, and this is your coronavirus update from Today Explained. President Trump announced on Sunday that Americans should continue to avoid gathering in groups of 10 or more for at least another month and maybe until June. That means avoid the office, avoid friends, avoid bars and restaurants and traveling. It is a big reversal of his earlier assessment that the country would be back in action by Easter. That reversal came after Trump's medical advisors warned him that as many as 200,000 Americans could die as a result of this coronavirus, with millions potentially getting infected. This morning, Dr. Deborah Birx, the

White House Coronavirus Response Coordinator, told a Today show that those numbers were optimistic, that if the United States does things perfectly from here on out, we might get in the range of 100,000 to 200,000 deaths. The latest numbers we have are just over 2,500 deaths in the United States and almost 150,000 confirmed cases. It was just on Thursday that I told you the United States had crossed the 1,000 death benchmark to give you an idea of how quickly the numbers are climbing. But the numbers might not be climbing as fast as they were in Seattle. Remember Seattle, where this was just so bad a few weeks ago? They think that containment strategies are starting to work there,

people are staying home, hospitals aren't overwhelmed, and the numbers suggest the spread of the virus has slowed. I don't know if any of the Backstreet Boys live in Seattle, but there's a video of them singing I Want It That Way together from a distance using video conferencing circulating online right now and it's something that isn't awful. The song still slaps and in one month it'll be old enough to order a drink. You can hit us with your

coronavirus questions via email todayexplainedatvox.com, via Twitter at today underscore explained or at Ramesfirm or give us a call and leave a message at 202-688-5944. That's our listener voicemail line. or give us a call and leave a message at 202-688-5944. That's our listener voicemail line. season long from tip off to the final buzzer you're always taken care of with a sportsbook born in vegas that's a feeling you can only get with bet mgm and no matter your team your favorite player or your style there's something every nba fan will love about bet mgm download

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If you have any questions or concerns about your gambling or someone close to you, please contact Connex Ontario at 1-866-531-2600 to speak to an advisor free of charge. BetMGM operates pursuant to an operating agreement with iGaming Ontario. Maybe you've noticed we've been doing a lot of episodes about the coronavirus. Like, every day.

But it's not just us. I'm willing to bet a lot of your favorite podcasts have been covering this pandemic wall-to-wall. Our friends over at Reset certainly have. In case you're not familiar, it's a Vox podcast all about how technology is changing our world. But lately, the show's been focused on the science and technology of this pandemic. And today we're going to bring you an example. A great episode Arielle and her crew just did on what the coronavirus does to your body. So the virus is basically a spiky ball. Those spikes recognize and latch onto a protein called ACE2, which is found on the surface of our cells. And like a key fitting into a lock, that is the first step to launching an

infection. Ed Yong is a science writer for The Atlantic, who often writes about the microscopic world. When we think about the catastrophe that the world is facing, I mean, this tiny little moat with just the barest scrap of genes has just brought the modern global order to its knees. And that's kind of humbling, I think. Ed says there's still a lot that we don't know about SARS-CoV-2. That's the name of the coronavirus that we're up against. But scientists have started to make a rough sketch of the virus's biology.

So today on the show, what do we know about how the virus works inside our bodies? This is Reset. Ed Yong, there are a lot of viruses that we're familiar with, and some of them we track regularly, like the flu. What about for coronaviruses? Do we know a lot about them? We very much do not. So flu is very familiar. So influenza viruses have been the cause of many pandemics in history. And we have a very, very established infrastructure for studying and combating them. With coronaviruses, it's entirely different. Research onto this group of viruses has been very niche for a long period of time. And partly that's because until this new one, SARS-CoV-2, came along, there were only six known coronaviruses that infect humans. Four of them are incredibly mild.

They circulate around the world every winter, and they cause maybe a third of cases of what we just call the common cold. So just sniffles, runny nose, sore throat, that kind of thing. And for that reason, few people study them. The other two, SARS and MERS, both cause much more severe diseases, but caused outbreaks that were easier to contain. What is up with this specific coronavirus? Why is it so successful? Why is it so good at spreading and infecting humans? Do we actually know that? So I would say that we don't. But I think based on what we know, we can at least try and put together a plausible hypothesis. The thing that especially makes this virus hard is that it seems to have a

long incubation time between first infecting a new person and then causing symptoms, during which it seems to be able to transmit to a new host. And specifically, the reason why its capacity to spread before symptoms is bad is that it allows it to really move around the world and within a country before people understand where it is. But is there a specific reason why it is so good at infecting humans specifically? Because this thing originated in animals, right? You're right. Based on the structure of the virus, it seems that there are a few possible qualities that allow it to spread so easily. It seems to stick to our cells more strongly and more readily, and it seems to be able to infect cells throughout a wider part of the airways.

So the virus is basically a spiky ball. So it's a ball with these proteins called spike proteins on the surface. Those spikes recognize and latch onto a protein called ACE2, which is found on the surface of our cells. And like a key fitting into a lock, that is the first step to launching an infection. This is also what the original SARS virus did. It had spikes which latched onto ACE2. But the specific shape of the spikes on this new virus of SARS-CoV-2, those spikes are much better at latching onto ACE2. They are a closer fit to the ACE2 protein.

What that means is that maybe it is easier for the virus to attach itself to our cells. And maybe that might mean that it takes a lower dose of virus to begin an infection. Again, this is all pretty speculative, but it makes sense given the tight fit between those two molecules. Okay, so the first thing is that this virus is better than previous coronaviruses at sticking to our cells. What's the second thing? Right. Now, then, once that first attachment is made, the spike protein must be split into its two separate halves in order for the infection to continue.

With the original SARS virus, that split did not happen very easily. But with this new virus, it can be done by an enzyme called furin, which cuts the two halves apart. And furin notably is widespread. It's made by the human body and it's found in a lot of different types of tissues. And again, that might be important for explaining some of the weird characteristics of this virus. Like what? Most respiratory viruses tend to infect either the upper or the lower airways. Okay. If they infect the upper airways, they spread very easily, but they tend to cause mild illnesses like a running nose or what have you. If they infect the lower airways, they tend to cause more severe illness like pneumonia,

but they are also harder to spread. SARS-CoV-2 seems to infect both sites. And maybe that's because it relies on that widespread furin enzyme. And maybe that might explain some of its sneakiness. Maybe it spreads easily when it infects the upper airways before then moving to the lower ones to cause more severe illness. It kind of sounds like it's just very good at what it does. So what are the odds of that actually happening? What are the odds of having a coronavirus that has this particular combination of traits? Right, sure. So whenever a new threat like this happens, there are always conspiracy theories about whether the new pathogen was designed or engineered to infect

humans. And certainly, it does nothing to quell those theories when you hear that it's so well adapted to infecting human cells. It sounds improbable that a virus that was lurking in some wild animal should have exactly those right traits and then somehow managed to find its way into a human body. But there are a lot of coronavir understand, that wild animals harbour millions, maybe billions of different kinds of coronaviruses. Even though the odds that any one of them might infect us very well and cause a pandemic of the kind we're seeing are very low, it actually becomes a reasonably likely scenario given how many possible viruses there are out there. This seems to be the one that by pretty bad luck had the right combination of traits

to effectively and stealthily spread among human hosts. After the break, what this coronavirus does inside the body, and whether you should be worried that this virus is mutating. This is Reset. and management software designed to help you save time and put money back in your pocket. Ramp says they give finance teams unprecedented control and insight into company spend. With Ramp, you're able to issue cards to every employee with limits and restrictions and automate expense reporting so you can stop wasting time at the end of every month. And now you can get $250 when you join Ramp.

You can go to ramp.com slash explained, ramp.com slash explained, r-a-m-p.com slash explained, cards issued by Sutton Bank. Member FDIC. Terms and conditions apply. Hey, just a reminder that you're listening to an episode of Reset in your Today Explained feed today. The show's digging into a lot of the scientific and technology-related stories around this pandemic right now. They just dropped an episode about what the word airborne means when it comes to the coronavirus.

And in the week ahead, they'll be covering the ventilator shortage in America and a video game called Animal Crossing that allows you to do all the things you can't do anymore in real life. Go fishing, hang out with friends. Arielle speaks with a couple that just got married in the game on Tuesday. Subscribe to Reset so you don't miss that. But for now, let's go back to Ariel and Ed. Ed Yong, science writer at The Atlantic. Part of what makes this coronavirus pandemic so scary is that it's killed a lot of people. And I'm wondering, what exactly does this virus do in the human body? Yeah, so again, we're left to speculate a little bit based on a combination of medical experience from people

around the world the results of i think only one autopsy to date and then our understanding of what similar viruses like SARS have done in the past so this is a likely scenario it may not be a 100 accurate one but it's sort of the best of what we've got right now. The virus seems to infect cells in the airways. It gets into those cells, reproduces, and then makes more copies of itself, causes the cells to die. Dying cells slough off from the airways and carry the virus down into the lungs where the infections proceed even further. So now you've got a bunch of dead cells, you've got fluid building up in the lungs. All of these can cause problems for people who are infected,

making it more difficult to breathe. So is that the reason why having ventilators has suddenly become so important? This is absolutely why ventilators are really important. The virus causes havoc in the respiratory system and makes it more difficult for people to breathe, is the long and short of it. But the really serious problems seem to occur not just as a consequence of the infection itself, but because of the body's attempt to fight that infection. So the immune system will typically mount some kind of defense against the virus.

But in some cases, that defense goes berserk. So the immune system radically overreacts and launches what is known as a cytokine storm. Is that where the fever comes in? No, the fever is part of the standard immune response. So fever, inflammation, and a lot of the symptoms that we typically associate with these kinds of viruses, that's just your body trying to fight back. A lot of the more severe problems that people have experienced is the are pretty common for a lot of new and severe infections. We saw them with the 1918 flu pandemic.

We saw them with, I think, the 2009 flu pandemic, a lot of these new emerging infections caused the immune system to overreact because nothing like them has ever been encountered by an immunologically naive population before. And that overreaction drives a lot of the more severe symptoms that we see among the most severe cases of COVID-19. So I'm glad you brought up the more severe cases because, you know, as we all know, some people experience mild fever and chills and they eventually get over it while others are being hospitalized right now. So do we know why that is? Do we know the reason why some people are affected so strongly while others are not? So I would say that unfortunately we don't. Certainly age seems to be a factor in that older people are at greater risk of more severe illness and sadly of dying from the disease. We don't really know why that is. It might just be that

older people are less able to mount an efficient initial immune response against the virus. But there are almost certainly other factors at work here. We know that even within an age group, some people are more likely to get severe disease than others. Maybe that has something to do with their genetics. I think that's very likely. It might have to do with, for example, the initial amounts of virus that they are exposed to. A lot of younger people who seem to be doing really badly are healthcare workers who might be exposed to much higher levels of virus because they're treating people who are very sick. Other aspects of the immune system, like people's pre-existing degree of immunity, not to this virus, but just in terms of how well their immune system is working, that might have an impact. There are lots of possible variables, and we don't know which one of those is important

right now, which means that we only have a very crude understanding of who is at risk and who is not. So right now we're working to squash a virus that we know still very little about, but that is replicating effectively in humans. And I'm wondering, that always comes with a chance of mutation, right? Where a virus's genetic makeup might change a bit, which is perfectly normal, except that some mutations are more important than others. So could the virus behind COVID-19 mutate and become even more effective? Certainly, it doesn't seem that way right now. None of the mutations that have thus far cropped up seem to be having a significant effect on the course of the illness or the course of the pandemic around the world.

Now, that was certainly true when I spoke to virologists about four or five days ago. Maybe that has changed already. The science around the virus is moving very, very quickly. Here's what I think is pretty safe to say. We can absolutely assume, and we can already see, that mutations will arise. It may well be that the virus changes in important ways in the future. I would be surprised if those changes lead to a much faster rate of transmission, for example, or a much higher rate of fatality, because this thing is

already very good at infecting people and very good at spreading. I think it is hard to imagine what would drive it to benefit from spreading even further to a will stress that one of the problems that we've had in dealing with this virus and this pandemic in general has sort of been a failure of imagination. It really has gone beyond a lot of what we thought might happen. And by we, I don't just mean the general population, but also a lot of people who think very deeply about issues of preparedness and the threat of pandemics. So, you know, I'm definitely not ruling anything out, but certainly I think we need a lot more evidence before we come to any conclusions about what the virus might or might not do in the future. And in the meantime, there's a gigantic fire that needs to be put out. Is there any chance that this fire might be put out by this coming summer? Will warmer weather just help this thing go away? I highly doubt it in the absence of other

stringent control measures. We're already seeing a spread in places like Singapore, which is in the tropics, or in Australia, which is only just coming out of its summer. I think the way to think about it is that this is a wildfire spreading among a field full of tinder. And expecting the summer to help is like expecting a very gentle rain to douse that fire. It probably won't happen, which is why other measures like getting hospitals ready and social distancing and all the like are really important. Clearly, we are in a very bad situation right now. And I think it drives home what some kinds of viruses are capable of and why we need to understand them.

But I think this goes well beyond basic virology or a sort of fundamental curiosity about the world around us. I think what this shows is that we as a society are exquisitely vulnerable. Even a country like America has just catastrophically flubbed its response to this new threat. So the virus itself is part of it, a crucial part that we need to understand. But this is an event and a story that encompasses all aspects of our society, everything from how equitably people can access healthcare to how we treat the eldest among us to our posture with the international community. Yes, the virus is the underlying cause of it, but there's so much more to understand and to improve about the entire world.

And maybe that's a lesson that I hope we will learn on the back of this. Ed Yong is a science writer at The Atlantic. I hope you learned something about this coronavirus today. And if you did, my guess is that your friends and family will too. So please share this episode with them. And of course, subscribe to the show. Reset is all about explaining the science behind these kinds of problems and the technology driving solutions

or occasionally making these problems worse. I'm Arielle Derm-Ross. This is Reset. To get in touch with me, follow me on Twitter. I'm at ADRS. We publish episodes three times a week, on Tuesdays, Thursdays, and Sundays. Later, nerds.