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--:-- Host (Noam Hassenfeld): We kicked off the week at Today Explained with an episode about how badly the COVID-19 surge in India is going. And we're going to end the week with a very different type of story about people who just haven't been able to put this in their rear view yet, people who haven't even come close. Today, we're going to hear about long-haul COVID. Something like at least 10% of people who get COVID continue to experience symptoms that science just doesn't fully understand yet. And our friends over at Unexplainable recently did a great episode getting into what we know and what still remains a mystery. about long COVID. Take a listen, and if you haven't subscribed to the show yet by the end of this episode, I'm sure you'll kind of be like, what am I doing even? So punch that button. Thanks for listening. This is Unexplainable. I'm Noam Hassenfeld, and I'm here with Julia Belouz, who's a senior health correspondent at Vox.
--:-- Julia Belouz: So I've been covering the pandemic since the beginning, and I've been looking into this group of coronavirus patients called long haulers. Okay. You've probably heard about them. You know, they basically stop testing positive, and then they stay sick, sometimes for a really, really long time. But I think what a lot of people don't appreciate is just how many of them there are. It's something like 10% of all COVID cases. Okay, so 10% of like everyone in the world who's tested positive? That's what the best estimates say. And it's at least 10%. So we're talking about more than 12 million people. That's like the size of many countries. And even now, over a year into the pandemic, we don't fully understand what's keeping these long haulers sick. I still am baffled by how much we still don't know.
--:-- Julia Belouz: And I think long COVID is one of those big unknowns. I talked to this doctor. His name is Craig Spencer, and he works in an emergency room in New York City. And I was especially interested in talking to him because he's not just a doctor. He's a long hauler. You know, the first few months were joint pain, fatigue, lost a lot of weight. You know, and I got up in the morning, my back hurt. My knees hurt. My muscles hurt. He's also had cognitive problems. A subtle but noticeable difference in concentration and ability to form new memories. But here's the thing. He never had COVID. Wait, what does that mean? How does he have long hauler symptoms if he never had COVID? He actually had Ebola.
--:-- Julia Belouz: So yeah, in 2014, I was working in Guinea in West Africa. I was taking care of Ebola patients, the majority of which likely wouldn't survive. He came back to the U.S. and he didn't realize he had the virus. And a lot of the symptoms for him actually appeared after he was discharged from hospital and his body had apparently cleared the virus. Okay, so this was years ago. Does Craig still have symptoms? Yeah, unfortunately, he still has cognitive symptoms. And yeah, we're talking years later. So in 2020, he's working in the ER and he starts to see these COVID patients. and he recognizes in them a lot of the things that he was struggling with after Ebola.
--:-- Julia Belouz: I saw a lot of people coming in saying they'd been to a bunch of different doctors, they'd been to their doctor, they know they had COVID. Their doctor basically told them that they didn't know how to help them or that it was all in their head. And that's when I think I started recognizing that this toll was going to be a lot bigger than anyone had recognized. Okay, so Ebola can cause long symptoms too. how similar are Craig's symptoms to what COVID long haulers are dealing with? They're actually pretty similar. So there's joint pain. I have pretty bad muscle and joint pain. Sometimes I have a limited ability to walk. There's fatigue. Sleeping 12 to 14 hours every night, taking a long nap in the afternoon. There's memory issues. It will be hard for me to remember this conversation in a few weeks.
--:-- Julia Belouz: But there are some other things that Craig didn't talk about. I had a fever for four months. Or some patients talk about issues with menstruation. During that one week of the month, I feel like I'm having almost a mini COVID. And talking to patients, I heard of a lot of other symptoms. So insomnia, tightness in the chest, waking up in the middle of the night with trouble breathing, persistent loss of smell and taste. Altogether, there's more than 100 symptoms that have been documented in the medical literature by now. And the fact that there are so many symptoms makes it really hard to solve this mystery.
--:-- Julia Belouz: So what does it mean if people with Ebola can have the same type of long-haul symptoms as people with COVID? So it means that like all of these reports we hear about like... Tonight health experts are raising concerns about an alarming new trend affecting some COVID patients. They're calling it COVID brain fog. The most frustrating symptom, the brain fog. This brain fog. They call it COVID brain fog. All these things that make it seem like what's happening to these long COVID patients is really unique and unprecedented and this like particularly scary new phenomenon, they're really missing a big part of the story.
--:-- Julia Belouz: And this isn't to minimize long COVID. It certainly scary but I think we're doing it a disservice when we see it in this broader context. These long hauler symptoms aren't at all unique to COVID. Are you saying it's just kind of COVID and Ebola? Is it even bigger than that? Oh my gosh, Noam, it's way bigger. It's well understood and it's been understood for decades that with every major pathogen capable of infecting people, a certain subset of patients who get infected that way will develop chronic symptoms that never go away.
--:-- Julia Belouz: I talked to Amy Pohl. She's a microbiologist. And she said this has happened before. In patients who got the initial SARS-CoV-1, 10-20% got chronic symptoms. We saw it with MERS. But it goes back much further. So I'm talking like Spanish flu, the 1918 Spanish flu, or even the Russian flu of the 1800s. Wait, so people in the 1918 flu or the Russian flu, they had the flu, then they recovered, and then some subset of them still had these long-haul symptoms way later? Yeah, so with the Spanish flu, people reported chronic sleeplessness, depression, fatigue. There are these reports from the Russian flu that kind of read a lot like what we talk about today with COVID brain fog or COVID dementia.
--:-- Julia Belouz: Again, yeah, the idea is that the virus is gone. It's apparently cleared their bodies, but their symptoms persist. So this whole phenomenon of long symptoms, I guess this is just common to how viruses work? Exactly. If COVID didn't cause chronic symptoms to occur in some people, it would actually be weird. And just to be clear here, in all of these situations, COVID, Ebola, SARS, people got infected with a virus, they stop testing positive, and then they still have these long-haul symptoms? So yes, but this is where I get to pull the rug out from under you again. Okay. Because the mystery of this whole thing is actually much bigger.
--:-- Julia Belouz: Long-haul symptoms aren't even unique to viruses. Wait, what do you mean it's not unique to viruses? So there's this whole world of conditions out there where people have these persistent symptoms, they go to the doctor, the doctor's diagnostic tools can't find anything wrong with them. And there's actually a term for these kinds of symptoms. They're called medically unexplained. Wait, wait, that's an official term? Yeah. Okay, perfect for our show. Exactly.
--:-- Julia Belouz: So we're talking about things like chronic Lyme disease, which isn't even caused by a virus. It's associated with a bacterial infection. And there's chronic fatigue syndrome, which may or may not be caused by viruses. And then long COVID fits in here because there's often nothing showing up in the nasal swab or blood tests or imaging to explain the symptoms that patients are experiencing, and yet they're suffering. Okay, so this category of medically unexplained symptoms is just sort of this grab bag of lots of symptoms that we don't really understand? Basically, yeah.
--:-- Julia Belouz: So this could even include stuff like post-ICU syndrome, unexplained back pain. Some people struggle with fatigue years after a cancer remission. But Amy is mainly focusing on medically unexplained symptoms following infections. The main theme that overlaps with a lot of them is an infection. It doesn't matter. It could be viral, bacterial, or in some cases, even fungal maybe, followed by the development of chronic symptoms in a certain subset of people who've gotten that infection. And it's the same central question. Why?
--:-- Julia Belouz: Oftentimes, the answer that these patients get is that it's in their heads. Doctors are frustrated, even more so patients are frustrated. They're suffering, usually untreated, undiagnosed, and they're feeling overlooked. So what do we do for patients like this? How do you treat medically unexplained symptoms? Well, I think the first obvious step is just to try to figure out what's going on with them. So one of the chronic fatigue patients I spoke to said, you know, that chronic fatigue syndrome wouldn't be medically unexplained if there was just more research into people who are suffering with that.
--:-- Julia Belouz: But here's the good news. Some scientists are actually looking into this, and they do have ideas about what's going on here. But just be prepared, because there's no easy answer. Coming up after the break, the leading theories to explain long COVID's medically unexplained symptoms, and why they all still fall just short.
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--:-- Host (Noam Hassenfeld): Unexplainable. Okay, Julia, we're back. Before the break, you were talking about how long COVID isn't just this unique COVID side effect, that there are all of these conditions out there that caused medically unexplained long hauler symptoms. But you were saying that we do have some potential answers here. What do we know about how COVID might be causing these lung symptoms? Yeah, so I talked to Amy about this. She's the microbiologist we heard from the first half of the show.
--:-- Julia Belouz: And she's working on this exact question right now. Yeah, so we're actually writing a paper now. And the way we're dividing the paper up is into like different scenarios for the development of lung COVID. Each of which doesn't have to be mutually exclusive with an X. like maybe two things could be happening in the same patient, but it's kind of like our top scenarios that we see. Amy has a bunch of scenarios outlined, but I want to highlight three in particular.
--:-- Julia Belouz: Let's start with scenario number one. The first possible scenario, and this doesn't even have to be in everyone, is just the most straightforward. That in some patients, the virus did not fully clear from every single body site. So you're testing negative for the virus, it's out of the blood, it's out of the nose, but it's still stuck in the tissues of the body somewhere, you know, in places where doctors aren't checking during routine testing. And these places are called viral reservoirs.
--:-- Julia Belouz: Viral reservoirs? Yeah. So what that means is the virus is still hanging out in the body, but just in places where it's harder to detect. So we know from other outbreaks that viruses can persist in the testes, in the heart, in the eyeballs. You know, the gut, even maybe the brain and some people who are really sick. And the immune system might still be responding to this virus. And that drives a lot of inflammation and symptoms. It could even be like parts of the virus, like its genetic material, the RNA, for example, lingering in the body.
--:-- Julia Belouz: And there's actually one team that looked at gut biopsy tissue samples from patients at about a six-month mark after COVID. And they found the virus's RNA and protein in some of those samples. So it might still be there. Some of the researchers I talked to called these viral ghosts. Okay, so scenario number one is that even though doctors might not be able to detect it in a routine test, some tiny bits of virus might still be in there hiding in viral reservoirs, and that's causing symptoms.
--:-- Julia Belouz: Right. And that's why some long haulers take issue with calling what they're experiencing post-COVID or post-viral syndrome. They'd rather call it long COVID or long-haul COVID because there might still be virus in their bodies and the symptoms for them aren't post. They're not over. They're still very real. Okay, scenario number two. The second scenario we're thinking of is that people already harbor other pathogens. Basically, you got COVID, so you have this new infection. Your immune system is sort of tied up fighting off this new virus, yet you still have other viruses that are dormant in your body.
--:-- Julia Belouz: So for example, 90% of people in the world already have herpes viruses. But in those patients, the immune system keeps them in a place where they can't replicate, where they can't express proteins. They're kind of controlled by the immune system. But COVID comes along and all of a sudden these other viruses, start to gain a foothold again. The immune system is caught up trying to fight COVID and these other viruses can take advantage of that to reactivate. And the symptoms you're having, they might not be from COVID, they might be from these other viruses that aren't dormant anymore.
--:-- Julia Belouz: So it's like when the cat's away, the mice will play or something like that with other viruses taking over while the immune system is distracted or busy dealing with the coronavirus? Yeah, yeah. Okay, let's hit scenario number three. A third scenario is that the immune system itself is causing tissue to be inflamed. So the immune system, which usually fights off foreign invaders like viruses, basically turns on the body itself. And under that scenario, we talk about molecular mimicry. Basically, the virus creates proteins that look like human proteins or tissue, and that kind of tricks the immune system.
--:-- Julia Belouz: And what can happen is when the immune system tries to target the virus, if it has a similar size and shape to a human tissue or protein, it fires on the human tissue or protein as well. So in this case, even after the virus is gone, the immune system is basically hurting the body. So we've got three possible scenarios here for how people could be testing negative for COVID, but still having long-haul symptoms. So number one, the virus is hiding out in viral reservoirs. Number two, the COVID virus is gone, but these other viruses have taken over. And three, the virus is gone, but the immune system has gotten kind of supercharged and has turned on the body.
--:-- Julia Belouz: Right. But because this is still medically unexplained, there's a bunch of other possibilities, too. The virus might have cleared the body, but it left these injuries. So, you know, there might be lung damage after COVID or problems with the heart. Amy's also investigating whether the virus might have messed up the microbiome. That's these trillions of bacteria, viruses and fungi that live in and on the body. And when the microbiome is out of balance, maybe that's causing symptoms.
--:-- Julia Belouz: Okay, so lots and lots of possibilities here. Are these all potential explanations for long COVID itself? Or could these help explain the broader range of medically unexplained symptoms like patients have with chronic Lyme or chronic fatigue syndrome? Amy thinks they can. So she's done a lot of research into these other non-COVID conditions, and she thinks some of the same mechanisms might be at play.
--:-- Julia Belouz: Because there's such overlap between long COVID and, you know, chronic symptoms after Lyme infection, the paper has relevance for all those diagnoses, definitely. But we still need more research. So of all of these ideas, everything from viral reservoirs to autoimmune disorders, do we know which one of these ideas could be explaining long COVID? Which one is at least closest to being right? Well, it might not be just one. Like in some patients, there might be multiple things going on.
--:-- Julia Belouz: Different patients might have different reasons for their long symptoms. But I think we've got to be patient here. It's going to take time to sort this out. And you have to remember, right, like we only discovered this virus just over a year ago. And it's going to take time to understand what's happening to all these patients. But I think one upside to this catastrophic mass tragedy that we all been experiencing is it was so many people getting sick right now roughly all at the same time researchers have a lot of data to work with.
--:-- Julia Belouz: Is that maybe why long COVID sort of caught a lot of people by surprise that maybe there are all these things out there that cause long-term symptoms, but we didn't have this critical mass of people that all got it at the same time? Is that how we may have missed this connection? Yeah, I think that's part of it, but I actually think the explanation goes a lot deeper. Medicine is really poorly set up to deal with these medically unexplained symptoms.
--:-- Julia Belouz: And what I heard from a lot of patients is that they're often having to convince their doctors that their symptoms are real. And one thing that was really frustrating to learn about is how this often cuts along gender lines. And so more women than men tend to have these like chronic, persistent, unexplained symptoms, including long COVID. And instead of investigating what's going on, the knee jerk reaction is to go back to, you know, like it's just in your head. It's anxiety.
--:-- Julia Belouz: I was at a meeting of seriously top researchers and that was really thrown out as like one of the top scenarios. Like women are very anxious, you know, and I'm sorry. But like that's been disproven many, many times again and again. Like, of course, you're going to feel anxious and depressed. But is that the reason for the disease? This is very stupid. It almost sounded like Vienna 100 years ago when doctors were still talking about hysteria.
--:-- Julia Belouz: Exactly. They're like still like bringing up stuff that like Sigmund Freud like thought about when he was like high on cocaine. I'm serious. Like it's like, no, just forget that whole thing. All that debate, that distracts everyone too. Because the new teams that come in are like, well, hold on, wait, like, should I be working on blood? Because maybe it's in their brain. And Amy was like, hey guys, we're scientists, do science. Collect blood, collect samples, and just start looking in it and doing good work on these people.
--:-- Julia Belouz: It sounds like it should be easy, but it's harder than you would think. So scientists ultimately don't really know what's going on here. And to top it off, instead of really trying to figure it out, they're often claiming it's in patients' heads. So how do we actually start helping long haulers? So there's one easy solution that surfaced, which is the vaccine. So some long haulers are actually reporting feeling better after they've gotten the COVID-19 vaccine.
--:-- Julia Belouz: One of the possible explanations for that is that they did harbor an ongoing reservoir of the virus in some body site, and they had not created enough of an immune response to fully clear the pathogen. And so if you boost the immune system, there's perhaps a stronger antibody response now that can help fully eliminate the pathogen from the body. But some other long haulers are saying they actually feel worse after the vaccine. Some feel the same. And so, yeah, it doesn't look like a silver bullet, unfortunately, just yet.
--:-- Julia Belouz: I mean, it sort of seems like the way we generally practice medicine isn't really set up for these kinds of medically unexplained symptoms. I think that's exactly right. And I actually asked Amy about this, and she talked about how it's really tricky for doctors because they don't have a quick diagnostic test. But the average person goes to see one doctor, they get a 7-10 minute long appointment covered by insurance, and that doctor barely has a chance to ask them anything.
--:-- Julia Belouz: And people have all these different symptoms that might have different causes, and so they probably need individualized treatment. Some patients develop really different long-term symptoms after COVID. I doubt there's going to be one magic thing that will help everyone. This means like doctors partnering with experts in other disciplines to help treat the symptoms that patients are experiencing and come up with these individualized treatment plans.
--:-- Julia Belouz: But to get there, the most important thing is just believing the patients. Yeah, I guess you can learn a lot from someone without just solely relying on a blood test or an x-ray or an MRI or something else that sort of seems quote unquote objective. Exactly. And if we'd really listened to the long haulers, we might have seen this coming. Disability populations and chronically ill populations, those were the people who were warning about this exact thing starting in February and March.
--:-- Julia Belouz: Like February 2020? Yeah. The other long haulers were talking about this before we even knew long COVID was a thing. Huh. Long haulers have it hard enough without having to convince the world that what they're experiencing is real. And talking to patients, what they really want to hear from doctors sometimes is just, I don't know. One of the best appointments I've had, the doctor said, like, we are seeing hundreds of people like you with neurological symptoms. Unfortunately, we don't know how to treat this yet. We don't even understand what's going on yet. But just, you know, you're not alone.
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--:-- Host (Noam Hassenfeld): This episode was reported by Julia Baluz and produced by Noam Hassenfeld, who wrote the music for it too. We had editing from Meredith Hodnot, Brian Resnick, and Jillian Weinberger, with mixing and sound design from Afim Shapiro and Christian Ayala. The Unexplainable team includes Bird Pinkerton and me, Manning Nguyen. I also fact-checked this episode. And Liz Kelly Nelson is the editorial director of Vox Podcasts.
--:-- Host (Noam Hassenfeld): Special thank you to the COVID long-haulers who spoke with Julia for this episode. Fiona Lowenstein and Hannah Davis. And thanks as well to Megan Hosey, Akiko Iwasaki, and Jamie Seltzer. As always, you can sign up for our weekly newsletter at vox.com slash unexplainable and you can find more unexplainable articles there too. And if this episode reminded you of something of a long-haul disease you've gone through of a different medical mystery, please email us. We're at unexplainable at vox.com. Unexplainable is part of the Vox Media Podcast Network and we'll be back in your feed next Wednesday. Thank you.
