Today, Explained - Why everyone is sick right now

Episode Date: January 11, 2026

How this season’s flu got supercharged — and why viruses may make you healthier. This episode was produced by Avishay Artsy, edited by Jenny Lawton, fact-checked by Melissa Hirsch, engineered by David Tatasciore, and hosted by Jonquilyn Hill.  Photo by Elisa Schu/picture alliance via Getty Images.  If you have a question, give us a call on 1-800-618-8545 or send us a note here.  Listen to Explain It to Me ad-free by becoming a Vox Member: vox.com/members.  Learn more about your ad choices. Visit podcastchoices.com/adchoices

At Medcan, we know that life's greatest moments are built on a foundation of good health, from the big milestones to the quiet winds. That's why our annual health assessment offers a physician-led, full-body checkup that provides a clear picture of your health today, and may uncover early signs of conditions like heart disease and cancer. The healthier you means more moments to cherish. Take control of your well-being and book an assessment today. Medcan. Live well for life.

Visit medcan.com slash moments to get started. Every year, hundreds of thousands of people from all over the world flock to Las Vegas for the Consumer Electronics show. And they spend a week trying to sell each other on the weirdest gadgets you've ever seen in your entire life. This week on The Vergecast, we're talking all about everything happening at CES. From the TVs to the AI gadgets to the humanoid robots that everybody is hoping might someday do your laundry and wash your dishes. All that and much more on the Vergecast wherever you get podcasts. It's been 18 days since I first started. getting those symptoms from whatever this super flu is going around.

I don't wish this flu will my worst enemy, bro. Stay inside, y'all. Don't get this flu. If you're a close listener of this podcast, you may have noticed that last week, I didn't quite sound like myself. Max grew up to write about... Sorry. I didn't realize it at the time, but I had the flu. And COVID, simultaneously.

But the real turning point came as junior... I'm sorry. It wasn't just me. It was like the entire team got sick. Cold, flu, even neurovirus. And we work remotely, so we did not get it from each other. It's everywhere. Well, flu cases in the U.S. are now at their highest levels on record.

That's going back to the late 90s. Roughly 11 million cases reported 5,000 deaths. In fact, 45 states tonight. reporting very high or high flu activity. The thing is, we've done this before, literally every year. And yet, here we are in 26, plagued again. I'm John Gwynne Hill. It's explained it to me from Vox.

And today, why this cold and flu season is so bad and how to come out healthy on the other side. First up, we need to understand why everyone is getting sick right now. Hi, I'm Caitlin Jetolina. I am an epidemiologist and a scientific communicator. She confirmed, alas, my flu-COVID combos, not that special. No, it is not. This is what we typically see every winter is just this rise in respiratory viruses, whether it's the common cold or the flu or COVID or RSV. And there's a number of reasons for that. But some of those reasons. reasons include cold weather, really causes viruses to spread very quickly, as well as social events.

We're seeing a lot of people we don't typically see. And the third reason is that these viruses just keep mutating. Which flu viruses are circulating right now? Like, what are the viruses going around? Yeah, so flu specifically, it's a very interesting year. And us epidemiologists are a little concerned that this year is going to be worse than previous years. And that's because one strain of the flu, it's called influenza A, H3N2. It's like an alphabet soup, but flu mutated over the summer

as it spread through Australia in the southern hemisphere. And specifically, it shifted from a J subclade to a K subclade. And this is the incremental change that happened when this virus spread. This year, the subclade K strain of the flu has already caused severe outbreaks in other countries, including Canada, the UK, and Japan, where it was declared an epidemic.

It causes the same flu symptoms, like fever, chills, aches, and chest pain that doctors see every year. But those symptoms could be more severe. You know, mutations are normal for the flu. In fact, flu is infamous for quick, unpredictable curveballs. flu can change in two ways. One is a, it's called a shift, which is a major overhaul that happens when two different flu viruses infect the same cell, swap genetic material, and create a new virus. This type of shift can, like, spark a pandemic because our immune systems have never seen

that version of the virus before. That is not what we have. What we have this winter is called a drift. And this means there's like a smaller incremental change that happens as the virus. spreads. It shouldn't trigger panic, but what it does mean is that our current vaccines will likely recognize some, but not all of this updated virus. It's just simply bad luck that H3N2 evolved so much in the months before our season really took off. And so together, these factors mean that the virus will be better at slipping past both vaccines as well as our prior immunity.

and that translates into more cases and more severe disease among those at highest risk. Okay, this makes sense because, you know, I get vaccinated, I got the flu shot, I still got sick with COVID and flu at the same time. And I was just like, I at least got a vaccine for one of these things. I thought I prepared myself. You did. And I will say, like, I want to be very clear that vaccination still matters, right? We're far from powerless. even though you got the flu shot, it's not designed to protect against infection. It's designed to prevent against hospitalization and you dying.

And given that we're doing this podcast, you didn't die. So did some of its work. It still means it'll be miserable and it's not fun, but it can help in that sense. So for people who didn't get a flu shot, is it too late now? Like, do they just have to wait this season out with their fingers crossed? No, it is not too late because several reasons. One is we haven't even reached the peak of flu yet, right? So we still have a whole way down the wave we have to go.

Oh, man. And so there's still going to be a lot of sickness out there. Flu vaccines take about two weeks for an immune system to really, like, kick into gear. So there's plenty of time to still be protected, and I think that's great. The other thing with flu is that there's many strains that circulate. So with COVID, you know, we were all used to like one strain circulating, like Delta or Amacan. But with flu, there's like two to three strains that circulate. So unfortunately what this means that if you get infected by flu once, you could get infected

by flu twice later on in this season. And so getting a vaccine can help protect from those other strains as well. So it's not just the flu that's going around right now, right? What else is going around? A lot. I mean, viruses love this time of year. So we see COVID. COVID right now is also starting to increase not as high as flu at all, but it is getting there. The other thing that's circulating wreaks havoc among infants. It's called RSV. We have other viruses like, you know, the common cold viruses that are certainly circulating. And then something that is not fun at all either is called norovirus. And this is like the stomach flu, diarrhea, nausea, that spreads not necessarily through respiratory trackways, but through touching, touching a dirty doorknob or eating contaminated food. So there's plumes of viruses everywhere you're going right now. And I think that there's a lot of things we can do to protect ourselves, but also just the reality a lot is circulating.

So if we want to boost our immune systems, what works and what doesn't work? Yeah. So, I mean, I don't know. You're probably on social media. There's so much out there. There's so many hacks out there. The rumor mill is really hot on ways to boost immune system. You go, like, 40 times.

You will feel like you're going to pass out, but it recycles all of the air in your lungs. so that no little viral molecules can survive. Did you know there's a quick, cheap, easy hack to boost your immune system? Hydrogen peroxide. I like to take this and put a couple drops in my ear. I'm gonna be taking my vitamin D and zinc on the daily. For the general population, dietary supplements

actually do not work in preventing or reducing severity of illness. Vitamin C or vitamin D just hasn't shown to help with respiratory viruses. Cold plunges. These have become increasingly popular for boosting immunity, but there's really inconclusive evidence and a lot of conflicting studies showing whether they're effective. Nasal breathing, saunas, a lot of these just have been really small studies. What works is the best thing you can do is give your immune system time to do its job. How we do that is a balanced nutrient-dense diet. Sleep, sleep is critical. This is when the immune system

executes most of its repair process. And so those who are chronically sleep deprived actually tend to get more colds than those aren't. So make sure you get a lot of sleep as well as hydration. Proper fluid balance really ensures your body can transport nutrients and immune cells. and remove a lot of these pathogens and waste products. Has flu come for you this season yet, or have you been able to avoid it so far? I don't, I mean, you're going to jinx myself, but I've been able to avoid it so far. But I'm a human too, and so we'll see. You know, I did get my flu vaccine.

I did get my COVID vaccine. My kids did too. So hopefully that will help provide some sort of protection. Coming up, why viruses are. so good at making us feel bad. We're back with Explanitent to me. I'm JQ. Carl Zimmer's written more than a dozen books about science. His latest is called Airborne, the hidden history of the life we breathe.

It's hard to write about science and not find yourself writing about viruses sooner or later because they affect everything. In other words, he thinks a lot about the tiny microbes wreaking havoc on our immune systems right now. Really, they hold sway over the whole world, literally. the entire planet is just packed with viruses that are infecting everything. And I mean literally everything, even other viruses. I want you to explain in super concrete terms what's going on with my body when I get sick.

So let's start real basic. What is a virus? Typically a virus is a tiny, tiny shell of protein that has some genes inside. So that's different than a cell. You know, a cell, it has genes inside of it, but it has all sorts of molecular machinery inside of it, too. Things for generating energy and all sorts of stuff. But viruses are just these stripped-down delivery systems, and they are evolved to be really good at getting into cells and taking them over to make new viruses.

That's all they do. Okay, right. And then your nose starts to run, you cough, you run a fever. Is that the virus talk? A lot of it is just our bodies fighting the virus. It's not that the virus is directly making you sick in that case. So, for example, if you get a cold and develop a fever, that's your brain saying, we're under attack. I'm going to set the thermostat to a higher setting because your immune system works better when it's hotter. And so that is just a way that your body is trying to fight the virus.

Now, if that gets out of control and you get a very high fever, that can be quite damaging in itself. You know, our immune systems are not perfect. They're amazing, but they can also cause us a lot of harm too. And so you may hear about viruses that cause, you know, really severe inflammation in the lungs that leads to pneumonia. This can happen with COVID and it can happen with influenza. It can actually sometimes happen with colds too. So a lot of what we feel when we are infected with the virus is just our body doing its level best to win the fight. You know, we were just hearing about the latest strain of influenza and that viruses mutate every year.

How do they do that and how does one strain become dominant over all these others? Viruses in general just mutate a lot. They do not have the kind of proofreading systems that, you know, our own cells have so that when they make new genes, that they can correct errors. So when our cells produce new viruses, it's a very sloppy process. And so a lot of mistakes get introduced. Now, that means that a lot of these new viruses that you produce when you have a cold or the flu, a lot of them are. so badly mutated that they're basically a dead end. And then there will be others that are fine, even with these mutations. And then there will be a few maybe that actually do a better job.

They actually have a mutation that helps them, you know, to bind more tightly to proteins on the surface of cells that improves their ability to get inside a new cell and infect. And so through these processes, you produce these incredible diversities of influenza viruses. And like we're seeing right now, one of them turns out to be really good and just better than the others. And it is just spreading like wildfire. We complain about the flu every year, but this is a very, very old problem, right? Viruses have been around ever since humans have been around. And in fact, viruses were probably around at the origin of life itself around 4 billion years ago.

You know, because bacteria get viruses. And when scientists study the genetic sequence of these viruses that infect bacteria and compare them to the bacteria themselves and so on, they can see that these are ancient, ancient lineages. So viruses are much, much older than we are. Why haven't we been able to find a cure for the common cold or the flu if they've been around so long? Well, I think because they've been around so long, that's one reason that we are struggling to find really effective treatments or really, really effective vaccines. They are exquisitely optimized for evolving and evading our immune systems. But, you know, there's no cold vaccine.

And the reason for that is that if you can even find a, recipe for a vaccine for one particular kind of cold virus, for example. The diversity of cold viruses is just vast. It's so vast. So you might be able to prime the immune system to fight against one strain, let's say, of cold virus, but there's so many others that the vaccine won't work against. So scientists are going to have to think differently. And they are, trying to think differently. You know, they're trying to find recipes for broadly effective vaccines against the cold or against the flu, maybe even universal vaccines. Yeah, you know, a listener actually called in with a question about that. Hi, my name is Jessica. I am sick for the third time,

courtesy of my 10-month-old in daycare. And it got me thinking. I thought we were promised a cure to the common cold once the power of AI was unleashed. And I feel like always. we've gotten this flop. So yeah, if AI is so powerful, when is it going to solve this for us? Artificial intelligence is really important for studying viruses, and scientists are using AI to speed up a lot of virology. There is a program, for example, going on right now called a human viral program. It's sponsored by the National Institutes of Health for $171 million.

And their goal is to take samples from thousands of people and try to identify every different species and strain of virus inside of them. So AI is helping right now to pinpoint pieces of DNA and RNA and say, hey, this looks like it's a virus and it looks like it's related to, you know, say, rhinoviruses, the viruses that cause colds. So that's happening right now, and that's really important to understand what viruses mean to our health. But anybody who would tell you that, you know, the AI that has just been rolling out in the past couple years is going to magically instantly give us a vaccine for the cold is not being honest with you. They're not being honest about how AI works, and they're not being honest about how much there is to figure out about viruses and vaccines. We're dealing, again, with millions of years of evolution, and for now,

evolution is still a lot smarter than we are, for the most part. There's just a lot of research that has to get done, and that's going to require a lot of sustained support for that research. And if people think that we can just save them a few million dollars here and there by cutting off this kind of basic research, and then also think we're going to get vaccines for cold, then they need to understand how science actually works. Okay, so that means the viruses have won this round, but our bodies have figured out a way to beat them at their own game. That's next. This is explaining to me.

I'm JQ. We know how viruses enter our bodies and cause chaos. So, is there a way to give our bodies a leg up in this fight? Hi, my name is Ellen Foxman. I'm a physician scientist at Yale School of Medicine, and I run a research lab that studies how our body fights respiratory viruses. One of the really interesting things we've been studying is the common cold. We've been trying to understand how our bodies fight this virus. And one of the really interesting thing that's come out of better testing for viruses is that not everybody who gets a common cold virus in their nose actually gets sick.

Only about half of the time to people who get those cold viruses even get sick. So one of the things that my lab is really interested in is what goes right, when you get one of these viruses in your body, but you don't get sick. Yeah, you know, one of the things you've studied is how immune systems respond to viruses and then what are immune systems learn from those viruses. Can you tell me a little bit more about that? Yeah, sure. So probably now after the pandemic, most people are familiar with the way that the immune system remembers viruses you've been previously exposed to. So that's what vaccines do. What vaccines do is they protect you against viruses by showing your immune system the size and shape of that virus so it recognizes it

and blocks it the next time it's exposed to. So that's one type of immune response called adaptive immunity. But there's also another type of immune response called innate immunity. And it's called innate because it's what we're born with. Like even babies are born being able to sense and defend against viruses they've never seen before. But for all of human evolution, viruses have been a huge, huge thing that our body has evolved to protect against. During the height of the pandemic, we took all these steps to not get sick. I'm wondering how those measures impacted our immunity, generally. Yeah, well, that's really interesting.

A lot of viruses stopped circulating for about a year during the pandemic, including the flu. And it's probably because the flu and COVID were transmitted in a very similar. way, you know? So by using the masks and hand washing and all that, we stopped transmitting the flu. And another very important virus that is very bad for babies called RSV. It just completely stopped circulating during the pandemic. So then when it went daycares and all these things opened up again, you had a whole extra year of babies that had not been exposed to RSV. And their bodies had no memory immunity of RSV. So all of the sudden, when every, everything reopened again. Within a few months, we had tons of babies getting RSV. And it was because

you had a whole backlog of a whole extra year babies that hadn't been exposed to that virus. Interestingly, rhinoviruses kept going around. Rinaviruses are the one virus that didn't go away. They kept going around even during the pandemic. Oh, man. Wow. It's like Colts feel unstoppable. I don't know what it is. They're unstoppable. They're a very successful virus. But what's really interesting is that with better ways of detecting these viruses, we now know that often we don't get sick when we get one of those. So that's what we need to figure out is why is it that sometimes we don't get sick when we get those viruses? And how can we make that happen more often? You've written about how while our immune system is fighting one virus, it could also be

protecting us from others at the same time. Can you talk about that? Yeah, I mean, that was one of the really interesting things that we found out during our research in our lab and also a lot of other labs during the COVID-19 pandemic. So there was this real mystery that little kids seemed to be relatively protected from getting severe illness from COVID compared to adults, which was kind of surprising. And it turned out that it had to do with the fact that kids had more activation of innate immunity, these innate defense mechanisms in the lining of the nose and in the lungs, because they're getting a lot of colds and sort of mild infections all the time just because they're new to the world and they're seeing all these viruses for the first time.

But getting these frequent mild infections is actually something that can rev up the immune system in the nose and in the lungs to provide, you know, a buffer or a little bit of protection against more serious viruses, like like the flu or like the COVID-19 virus. So how does that work? So rhinovirus is the typical virus that causes the common cold, but it has to do its business and do its viral replication really fast because immediately it's very good at turning on innate defenses that block it in the nose, whereas flu is much better at preventing those defenses for going on for a few days. So the flu can keep going unchecked for a few days and make you much sicker.

So one of the really interesting things that we and others have found in our research is that when you have a rhinovirus that activates those defenses really, really strongly. And when your body is reacting, if the flu's there, it will react against the flu as well. So that's how cold viruses may be beneficial in alerting your body to be on the defense against viruses when flu is also going around. That's so interesting. You know, I have friends with kids and it feels like they're always coming down with something. Their kid is always bringing something home.

But it sounds like for their kid or even for them, you know, being sick is actually helping them in a way. Well, that might be going a little too far to say being sick is helping. But it's sort of interesting to see that there's this whole spectrum. On the one hand, you can get one of these viruses and it doesn't do much to make you sick, but it just revs up your immune system. And that can actually be a good thing. Or you can get a cold and it's a nuisance, but it might be helpful, you know, for the next. few weeks in helping you not get other viruses, or you can get really sick, and in that case, it's no good. But if you could find a way to sort of stimulate the innate immune system in the right

way, maybe you could find new ways to protect against cold viruses. So that's what we're really interested to figure out. That's it this week. Rest up, hydrate, and y'all get that flu shot. Coming up, we're going to be talking about the show on everyone's lips right now. Rated Rivalry. Yes, it's made waves because it's steamy, but also because of all that pining. We want to know, what's your favorite TV romance? Call us at 1-800-61845 or email AskVox at Vox.com. This episode was produced by Avashai Artsy and was edited by Ginny Lawton.

Fact-checking was by Melissa Hirsch, and engineering was by Brandon McFarland. Miranda Kennedy is our executive producer, and I'm your host, John and Hill. Thank you so much for listening. I'll talk to you soon. Bye.