Today, Explained - A vaccine for RSV

Episode Date: November 10, 2022

A respiratory virus called RSV has a lot of kids in critical condition and hospitals overwhelmed. Vox public health reporter and epidemiologist Keren Landman explains newfound hope for a vaccine. This episode was produced by Victoria Chamberlin, edited by Matt Collette, fact-checked by Laura Bullard, engineered by Paul Robert Mounsey, and hosted by Sean Rameswaram. Transcript at vox.com/todayexplained   Support Today, Explained by making a financial contribution to Vox! bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices

A lot of kids in America are sick right now. There's the flu, there's still that lingering pandemic, but the big problem appears to be RSV, Respiratory Syncytial Virus. Authorities say it is the worst pediatric care crisis in decades. Well, here's an alarming number. 99% of pediatric beds are now full at one of the nation's top hospitals.

I'm worried about the kids getting sicker and the lack of beds. Being able to fit them all in are now full at one of the nation's top hospitals. I'm worried about the kids getting sicker and the lack of beds, being able to fit them all in for the care that they need. And it is a virus very well known to all of us, whether you realize it or not. It is an extremely common cause of colds every cold season. But for babies, this is no common cold.

It's critical. And this has been a particularly brutal year. The hospitals are at or above capacity and the emergency departments are seeing double volumes from what they were ever seeing before COVID. But it's not all bad news. We might have some viable vaccines. The details are forthcoming on Today Explained. BetMGM, authorized gaming partner of the NBA, has your back all 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 BetMGM.

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Ontario only. Please play responsibly. 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 anirm here with Vox's Dr. Karen Landman, who has some gnarly details about RSV to kick off the show. Yeah, once you see it, you never forget it. The main thing that RSV does is it attacks the lining of the airways.

And that leads to inflammation, so the lining of the airways. And that leads to inflammation, so thickening of those airways. And in response, your immune system makes a lot of mucus, which basically further narrows the airways. It started out with just cold and then all of a sudden it just was gunked up. It couldn't breathe. It's almost like if you take a thin plastic straw and now because of the inflammation, it's suddenly made of this thick cardboard. And not only that, because it's got all this junk on the inside, it's like there's peanut butter on the inside. So try to move air through a peanut butter lined cardboard straw. It's going to go a lot. It's going to take a lot more effort to move that air than it will if you have that, you know, a thin plastic straw. Sorry,

that's kind of gross. What a haunting visual, Karen. You're welcome. The difference between kids and adults when it comes to respiratory viruses is the size of their airways. In babies, they both start and end much, much, much smaller than they do in adults. So anything that thickens that airway and narrows the space through which air moves is going to have a more severe impact on a baby just because your starting size of that tube is so much smaller than it is an adult. And so these babies cough. They make this like terrible hacking, juicy cough.

And then they also wheeze a lot or what sounds like wheezing a lot because they're moving air through just a much, much narrower space. It makes a kind of whistling like wheezing a lot because they're moving air through just a much much narrower space it makes a kind of whistling wheezy noise. Her ribcage very clearly when she was doing every single breath it was going in and out in and out. They work to move the air through their airways much harder than they would if their airways were not clogged like this so that that looks different in babies and adults because there's so much more cartilage in the rib cages. So you really see them sucking in the spaces between their ribs, sometimes denting in the fronts

of their chest, just above their belly, just because their chests are working so hard to try to get their little lungs to fill with air. We were definitely terrified, especially when we saw that she needed to go on oxygen and had the tubes in her nose. I did not think RSV could do this to babies. Like, I did not know that they could be intubated, that they could almost die, that they could code.

It's really alarming to see for parents and even for health care providers, even the ones that have seen a lot of sick babies. RSV babies just look like they're really struggling. It's hard to watch. And all peanut butter aside, this can kill these infants. It is killing these infants. It kills lots of infants. I mean, in the U.S., where we have pretty great pediatric care, our other many, many issues of access and equity notwithstanding,

we lose 100 to 300 babies a year to RSV, which is a lot, actually. Babies should not be dying of infections like this. But globally, you know, this disease causes many, many more pediatric deaths just because they do not have access to the kind of respiratory support, the kinds of machines and medications and care that we do here in the United States. You know, the estimates vary depending on who's doing the math and how exactly they do it, but it's upward of 100,000 babies per year that die globally of RSV and probably closer to 120,000 to 150,000 babies a year. It also causes lots of illness that leads, quote, only to hospitalization, which is also not great. We hospitalize about around 60,000 babies a year in the United States. And, you know,

being hospitalized, as any parent of a small baby will tell you, it's super stressful. It's also, you know, it's just not a situation that anybody wants to have their baby hospitalized. So those are important as well. But it's also a very, very important cause of hospitalization and death in adults. You know, we really don't recognize RSV as much as we should as a cause of pneumonia in adults. But in people over 65, we hospitalized 120,000 a year in the United States for RSV-related causes, and many die as well. It has a huge impact. Why are kids getting so sick right now if this has been around forever? What feels different about 2022? What a lot of folks think is going on is that RSV just hasn't had a chance to circulate at the rate that it's now circulating for a long time. Even though kids went back to school last fall, and there was a big surge of RSV last

fall to go along with that, adults were still masked, and a lot of them were still not back physically in the office. So what's happening now is that not only are kids back in school, but adults are also circulating and mostly unmasked. So RSV, it circulates pretty widely every fall. And a lot of people get infected with RSV every year, sometimes multiple times a year. And that kind of leaves them with a level of antibodies that can prevent subsequent RSV infections from being super, super severe. If you go several years without an RSV infection, antibody level

wanes down to the point where your immune system, when it sees RSV again, it's like it's the first time all over again. And so it responds more strongly to that infection. So we now have also, when you think about it, babies who were born during the pandemic, a lot of them never got exposed to any colds because they've been either kept home or masked, or they've just been in environments where they have not gotten a lot of exposure to those things, to viruses. So they haven't had a chance to build any immunity. So new infections now, whether RSV or not, are meeting immune systems that really don't have a lot of protection against them or much experience with them. So it's a bad situation in that sense. What is the impact right now of this surge on the health care system? The impact right now is largely unfolding in children's hospitals

or on pediatric wards of general hospitals. A lot of those hospital beds are full. A lot of the ICUs are full. The intensive care units are really close to capacity. And most importantly, where they usually have, they have 52 spaces in their beds in their emergency room to see kids. And they had 125 people physically in the emergency room a few nights ago. And that means that 70 odd people are waiting to be seen at any given moment. And that's a really bad scene, as you can imagine, in an emergency room that's just not equipped for that. It doesn't necessarily mean that a larger proportion of the people in the emergency room are sick. But it does mean that if you show up with a broken arm or with something else that's not RSV, you're going to wait a lot longer to get care. And if you happen to be somebody whose illness is moving quickly and you're getting sick more quickly, it's not a super safe place for you. So when you have your kid wheezing, really fighting for air, and you know that the respiratory person has like 60 other kids they have to deal with, it's a painful process, a helpless process. As we learned in COVID, your health care system is only as strong as the people who are able to staff it, right?

You can have 100 beds in the hospital, but if you only have enough nurses and respiratory therapists and doctors to take care of 80 patients, you functionally only have 80 beds. We already had a pretty strained health care staffing system before COVID, but like 20% of health care workers either quit or were laid off during the earlier parts of the pandemic. And a lot of those folks are not coming back to bedside patient care. That means that as stressed as our healthcare workforce was before the pandemic, it's much more strained now. So there's just a lot less slack in the system to handle surges like this.

You know, where in the past there was a pool of, for example, travel nurses that could very easily be flexed on during a seasonal surge like this, almost like any other seasonal worker that you could hire and then not keep on staff for the rest of the year when you didn't need them. That pool just no longer exists. If it exists, it's a lot smaller. So there's just a lot less reserve, a lot less ability to scale up our healthcare workforce when we need it during surges like this. And that is in large part, not entirely, but in large part a consequence of the pandemic. But is this surge we're experiencing right now

forcing people to take this a little more seriously this year? This is the first time that I've seen RSV in the headlines to the degree that it is now, and I hope that people will take it more seriously as a consequence. And I think equally importantly, even though the general public may not take RSV seriously, the medical community really does. And that's a good thing because they've been working on some really important solutions to RSV and have been for years, really decades. There's some really exciting stuff coming down the pike. Pfizer just releasing data on trials for a shot for pregnant women to combat

the respiratory illness that is hitting children so hard nationwide. Pfizer plans to submit the vaccine for FDA approval by the end of the year. The vaccine is given as a single dose shot. Really incredible advances along prevention lines that I think are going to be real game changers for RSV's effect on babies and adults, both in the U.S. and globally. We love a little hope, Karen. Yes, hope is good. Support for Today Explained comes from Aura. Aura believes that sharing pictures is a great way to keep up with family.

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Today Explained, still here with Karen Landman. Karen, you mentioned a moment ago that there's good news here. There are some vaccine trials. We recently got some news. Why isn't there already a vaccine for RSV? Oh, Sean, it's a long story. It starts back in the 1960s with an effort to create an RSV vaccine, which really speaks of just for how long RSV has been a scourge on the scene of pediatric illnesses.

A bunch of scientists tried to create a vaccine. It didn't go well. The kids who received the vaccine and then got infected through the course of their lives with RSV actually did worse than the kids who didn't get the vaccine. And two of the kids who got the vaccine died. Wait, how did these kids die? Without getting too far into the weeds, basically, we didn't really understand how different babies' immune systems are from adults back then.

And the vaccine wasn't weakened enough, and it ended up causing these babies to have a stronger immune reaction to their RSV infections than they would have had without the vaccine. We know a lot more about babies' immune systems now than we did back then. But even over the next few decades after the 60s, just because there was so much fear after that failed vaccine trial, that it just really slowed vaccine development related to RSV for a really long time. Yeah, I can imagine, given recent experience, that that really would have slowed down the machinery here. Does anything happen between then and now?

Surely, yes. Yes, very much so. So something really exciting happened in 2013 when a scientist named Jason McClellan, who's now at the University of Texas in Austin, figured out how to solve an important problem in RSV vaccine development. Okay, so that's a bit of a story. We're trying to do a lot of work there for structure-based vaccine design for HIV-1. And it was challenging, and maybe because HIV is a really difficult virus. So I thought, why don't we try and work on RSV, maybe a more tractable virus. Basically, the issue was that RSV, when it's just circulating in your blood, before it actually invades a cell, the proteins on its surface, which would normally be a target for a vaccine, have a certain shape. Once the virus invades

your body's cells, those proteins take a different shape. You really ideally want to target the pre-invasion shape of the virus proteins because that way you can actually have your body's immune system recognize the virus before it invades yourselves, right? But the problem is that when they would try to isolate this protein in the lab and get a look at its shape in this sort of pre-invasion, pre-fusion stage, it really was unstable and they just couldn't get it to sit still long enough for them to get a clear picture of what it looked like in order to create a vaccine to attack it. But in 2013, McClellan figured out how to keep this protein stable enough in its pre-fusion, pre-invasion stage so that they could

actually get a good enough sense of what it looked like to develop vaccines to prevent it. And that was a huge step forward for this field. So it really sparked an enormous amount of scientific breakthrough afterwards. And it was hugely important for hastening the development of the COVID vaccine once SARS-CoV-2 came on the scene. This RSV research helped the COVID vaccine? Crazy, right? We started working on the structure. They began coordinating with Moderna to get the first vaccine formulated. Same basic principle. The spike protein on the surface of the virus that causes COVID is also not super stable in its pre-fusion phase. And they needed to find a way to stabilize that in order to make a vaccine to target it.

So vaccine developments made in an effort to target one particular pathogen are really portable to efforts to target vaccines to other pathogens. And this was a really exciting example of that. So how does this 2013 development set us up for the most recent development, which is that there's this new Pfizer vaccine candidate? This 2013 development actually set us up for a whole bunch of new vaccine candidates and other products that are coming on the scene to help protect both babies and adults from RSV. Novavax Prepare Phase 3 trial of the RSVF vaccine for infants via maternal immunization aims to protect infants when they are most vulnerable to an RSV infection. And the Pfizer vaccine candidate is just one of those, but it's an important one because it's probably going to be the one that gets used most often, at least in the early stages of this.

Pfizer saying its vaccine against the respiratory virus is safe for pregnant women and effective in helping protect their babies. This vaccine targets the pre-fusion, pre-invasion protein on the surface of RSV meant to be given to people who are carrying pregnancies in order to allow the antibodies that are stimulated by the vaccine to be transferred naturally to the fetus, to the baby that's inside during the pregnancy. Fancy. It's not as uncommon as you might think. There are a lot of vaccines that are given to pregnant people

with the express purpose of boosting antibody production so that those antibodies get transferred to the baby that they're carrying before the baby is born in order to protect the baby from a whole variety of infections in case they're exposed to them in the very early months of life. Flu vaccine, COVID vaccine. We give other vaccines during pregnancy for this exact same reason. And this is the way I think most babies will end up being protected from RSV. And the reason we do that is because babies' immune systems are much, much less mature than even younger children's are. They're just not capable of producing a lot of antibodies in the first few months of life. So they really rely on the antibodies that they get from the person who carries them while they're pregnant.

How well does it work? that Pfizer released early last week. The vaccine prevented 69% of severe RSV cases in babies six months and younger. It is really nice. So what we mean by severe cases are cases requiring medical attention. So anything where a parent said, oh, this is too scary. I'm taking this kid into the clinic, to the hospital, to the doctor's office. So that's actually a lot because that means that it's also preventing a lot of hospitalizations and also a fair amount of deaths. So it's a big deal. And this is just one of several RSV vaccines in development? Right. And I want to be clear, when we say vaccines, it's not just vaccines that are being developed. This maternal vaccine is, I think,

the chief candidate for a maternal vaccine that's out there right now. But there are also at least three monoclonal antibodies under development. Some of us might remember hearing about monoclonal antibodies during COVID. I caught it. I heard about this drug.

I said, let me take it. It was my suggestion. I said, let me take it. And it was incredible the way it worked. Incredible. It's basically a synthetic version of the naturally produced antibody that you get when you get vaccinated. This will primarily be used in babies who are born before the person carrying them has a chance to get vaccinated with a maternal RSV vaccine. So say your baby is born at 30 weeks before you had a chance to get an RSV vaccine or you weren't able to get prenatal care. Your baby can still get monoclonal antibody instead of the antibodies that the parent

would have passed on to them and still be really well protected in those first six months of life when, I should also mention, RSV is most dangerous. Okay, you've got the Pfizer vaccine, a whole bunch of other ones. When do one of these things get approved? Is it Operation Warp Speed Part 2? Oh, Sean, LOL. No, my sweet summer child. Operation Warp Speed is not going to happen again for a long time. We'd all love to see that kind of government investment in vaccines. But that was a rare event for our

government to fund vaccine development to that degree. So this is... Huh. Even with dying babies? Yeah. Sorry. You know, what Operation Warp Speed did was it scaled up the discovery process in a way that RSV vaccine doesn't really need. What RSV vaccine needs now is, you know, approval and licensing and recommendations in the U.S. And Pfizer's vaccine is already at a place where they are going to be submitting their data to the FDA for their review in the coming months, probably in the coming weeks even. And that means that the pathway to scaling up production to make it available to parents carrying babies to protect their babies could happen in the next one to two years. That's really exciting. The monoclonal antibodies are probably also on a similar time course. There are a couple of vaccines that are

under investigation. I should call them vaccine vaccines that are under investigation. I should call them vaccine candidates that are under investigation to be used in babies directly. So these would look a little bit more like the vaccines that adults are used to, meaning vaccines that you get in your arm and they protect you rather than the kind that a parent gets to protect their infant. And then there are all these vaccine candidates and adults, one of which I think is also on track to be approved in the next year or two. So these are going to be moving forward, funded by pharma themselves, to do a lot of work on getting approved, licensed, and recommended, and then have production scaled up.

And in the meantime, Karen, what do parents who are freaking out about this surge in RSV plus COVID plus the flu season do to protect their kids? We've learned a lot of lessons from COVID, right, about what it takes to reduce the spread of a respiratory virus. These measures may not be extremely popular because so many of us are so tired of them, but they really work. Washing your hands, right? Ventilating your spaces and wearing masks, like wearing masks when people are sick or when you're in crowded spaces. It really works to protect kids and adults from these infections. So a lot of the skills that we learn to keep each other healthy during COVID are applicable now and not just

when it's COVID that's surging, but also when things like RSV are surging. So I hope we can apply some of those lessons to this current health crisis. Dr. Karen Landman writes about science and health at Vox. Our show today was produced by Victoria Chamberlain. She had help from Matthew Collette, Laura Bullard, and Paul Robert Mounsey. It's Today Explained. Thank you. you