Disclaimer: This episode of Kids HealthCast by We Cornell Medicine was recorded on May 19th, 2023, and is reflective of the latest information at that point.

Melanie Cole, MS (Host): There's no handbook for your child's health, but we do have a podcast featuring world-class clinical and research physicians covering everything from your child's allergies to zinc levels. Welcome to Kids Health Cast by Weill Cornell Medicine. I'm Melanie Cole. And we have a panel for you today with Dr. Sallie Permar, she's the Pediatrician-in-Chief at New York-Presbyterian Hospital/Weill Cornell Medical Center and the Chair of Pediatrics at Weill Cornell Medical College Cornell University; and Dr. Karen Acker, she's an assistant attending pediatrician at New York Presbyterian Hospital Weill Cornell Medical Center and an Assistant Professor of Clinical Pediatrics at Weill Cornell Medical College Cornell University, and they are here to discuss RSV and the new vaccine for children.

Melanie Cole, MS: Doctors, thank you so much for joining us today. Dr. Acker, welcome back. You're always a great guest. I'd like to start with you. Have you seen an uptick in RSV and other respiratory illnesses? And while you're telling us what you've been seeing, please tell us what RSV even is and how it differs from the flu and COVID, similarities, differences because they are similar in many ways.

Dr Karen Acker: Yes. Thank you, Melanie, for having me today. So, yes, we have seen an uptick in RSV and in respiratory viruses this past year. And so first though, I would like to tell you a little bit what RSV was prior to the pandemic, because this helps understand what changes we've seen. Prior to the pandemic, a typical RSV season would start in October, peak in either December or January, and then end around April. And every year, there was a significant burden of disease. We would see up to 80,000 hospitalizations per year in the United States in children less than five years. And RSV hospitalizations accounted for almost 20% of the hospitalizations during this time.

We saw a few big changes in the pandemic and the so-called post-pandemic years. One was almost the absence of an RSV season during the years 2020 to 2021 during that season. The second was the change in seasonality that we saw the year after in 2021 to 2022, where RSV started in the spring, which was pretty peculiar, and then continued until the following winter. But it was really this past year, this past fall and winter 2022 to 2023, where we saw this unprecedented increase in cases in hospitalizations, where they at least doubled compared to prior typical RSV seasons.

Your second question was about differentiating all these different viruses we see, particularly influenza, RSV and SARS-CoV-2, which causes COVID-19, and they're all similar in that they all can cause respiratory illness with runny nose, cough, fever, anything ranging from your mild cold, all the way to severe disease resulting in hospitalization and even deaths. But some of the key differences are really in that risk and severity of disease in children, particularly young children, infants.

RSV affects almost all children by two years of age. So really, any child will have had an RSV whether you've known it or not, by then. And most commonly, they'll get runny nose, cough, maybe a fever. But of the three viruses, RSV, influenza and COVID, I would say RSV probably is the highest risk of more severe disease, where 20-30% of infants with RSV will require hospitalization. And this is really because RSV infects the lower airways of our lungs or bronchials and causes something called bronchiolitis. And because children, particularly babies and infants have such small airways when they get plugged up with mucus and inflammation, that can cause severe respiratory illness. Influenza can do that similarly, where it can go from the mild cold all the way to severe disease. And young children are also particularly susceptible to severe influenza infections. Kind of the outlier, I would say, is COVID, where we haven't seen that same burden of severe illness in young children, where most young children will have either mild symptoms or maybe no symptoms at all.

Melanie Cole, MS: Yeah, that was kind of a bit of a blessing during the pandemic that it wasn't affecting our children quite as much. But as we're talking about RSV, Dr. Permar, tell us a little bit about the vaccine. Is there a vaccine? Can you discuss the urgency to approve that RSV vaccine for newborns and the efficacy of those vaccines currently under review?

Dr Sallie Permar: So, thank you for having me. And thank you to Dr. Acker for that very clear explanation of why RSV is so challenging for pediatric populations and why we are so interested in these vaccines making it to market so that we can really impact the next RSV season that we imagine will be here in a short number of months.

The new vaccines are really decades of basic science coming to fruition, which is so exciting to see. So many years ago, there was a scare with vaccine development. Soon after the measles vaccine was so successful, the rubella vaccine was so successful. Then, other similar types of either inactivated vaccines or live attenuated vaccines were being tried for major causes of illness, including those in childhood. And one very big target was RSV because of all the burden of disease. However, one of the inactivated vaccine types, while it provided some protection, in some children that got the infection after vaccination, they actually had enhanced respiratory disease. And so, that was a big setback for the entire vaccine development and especially for this virus that is so problematic at the younger ages.

So then for years, people worked on, an improved vaccine, worked to understand why did that first inactivated vaccine fail and how could we overcome that through basic science? And it really took some pediatrician scientists and working together with structural biologists and other vaccine developers to come up with the answer really, which was to modify the main protein on the virus that is required for any entry into human cells. And that's called the F protein or the fusion protein. They were able to stabilize that protein in a way that makes it susceptible to antibodies that our immune system can make. And once that change was able to be identified, the ability to elicit or, once you get the vaccine, to make great antibodies against the virus, became very simple actually. And so, that vaccine type has been working through all the processes through animal studies and into human trials and recently approved as an elderly vaccine. But of course, the burden of the disease is really at the youngest ages. And so, there is current review of this product to be given in pregnancy, so that moms can make that great antibody response against this stabilized fusion protein that then will be passed on to their infant and be present at the time of birth, which is a huge opportunity and was shown to reduce hospitalization of infants for RSV by almost 80% and so, really a huge benefit.

There is one other type of vaccine that is also going through reviews that will be another opportunity to again reduce the burden of this very persistent virus in the pediatric population, which is building on an older vaccine that had been very effective in young kids, which is a monoclonal antibody. So, a passive vaccine where you provide a good antibody response to the baby. The version that we had called Synagis was used in high-risk infants, like premature infants, infants with cardiac disease, and worked very well. However, it had many impracticalities, one being the cost and one being that you had to get it monthly and it was a shot monthly, which was hard to implement. A better version of that is coming through now with some changes that make it long-acting, so a more potent antibody, and it lasts for six months of time. So, one shot at birth can protect infants as well. So, that's another product that's coming through. Really exciting times.

Melanie Cole, MS: Well, it certainly is. And it's so important what they're doing right now. But Dr. Permar, your Department of Pediatrics will be advocating for patients to receive this vaccine. In this age and vaccines, I'd like you to speak about the importance of them. How do you think this will go over with parents? And what would you like them to know about you are all the experts, you are our gold standard there to protect our kids and keep them healthy and safe and happy? What do you want parents to know about the fact that we are advocating for this now?

Dr Sallie Permar: There's going to be a lot for parents to know and learn about with these two different vaccines that are coming down the pike, one for third trimester of pregnancy and one for delivery to the infants. First big thing to know is that unlike the COVID vaccines that were never tested in pregnant women before they were approved for pregnant women, basically because there was such a urgency to put that vaccine out that it was to the benefit of pregnant women that the first vaccine that came through human trials was given the choice for pregnant women to be included in the studies. Later, it showed that that vaccine was very effective in pregnancy and actually that virus was more severe in pregnancy. So, it was really important to give in pregnancy, but we didn't really know it from the initial trials.

What's different about this vaccine is that it was tried specifically in pregnant women, that the safety and the efficacy and the immune responses were all reviewed because this vaccine was designed specifically for pregnancy. So, this is different than what pregnant women faced in the COVID vaccine rollout of not really having data on whether that vaccine was safe and effective in pregnant women. It was later found that it was. But this time, we know that it has been tested in that population, looks very effective in that population, and the safety's being reviewed very carefully to show the benefits do seem to outweigh that of any potential risk. The committees are reviewing that right now. But as a pediatrician who sees the burden of disease from all newborns are at risk for severe disease from RSV, then I would say it's still definitely going to be something I recommend to patients.

Dr Karen Acker: And I'd like to add to what Dr. Permar said, and really in terms of giving this to pregnant women to protect their babies, is that the reason we need to do that is that it's really those infants less than six months of age we're at the highest risk for respiratory complications from RSV. And so, I just wanted to highlight that it's a very cool methodology to target young infants when they're at such high risk.

Dr Sallie Permar: Yeah. And adding on to that, Karen, is that it takes a few weeks to respond to an active vaccine, right? We expect you don't have the maximal immune response for several weeks, maybe even after a second dose. And that's why in these infants, they can get sick in the first week or two or three of life. And so, there really is not time to give an active vaccine at the beginning of life to protect them in the time window that's needed. And that's why this innovation of providing the vaccine to pregnant women to then pass on preformed antibodies is so innovative and also can provide protection to the pregnant mom as well, because pregnant women can also get a bad cold from RSV and even can have severe disease. So, there are benefits to really two parties from one vaccine.

Melanie Cole, MS: Dr. Permar, what about children that are just a little older than newborns, six months, a year, two years? Because it still affects those little kiddos, tell us a little bit about what's going on in the vaccine world for them.

Dr Sallie Permar: You're totally right that this is going to need to be a complement of vaccine strategies because even though vaccinating pregnant women to both protect the pregnant woman against severe disease and pass on great immunity to the baby, but it doesn't last, it wanes over time. And throughout human evolution, the goal was that then the infant's immune system gets educated by exposure to various pathogens and then can respond on its own once the maternal antibodies wane.

So, the maternal vaccine is not going to be a solution that lasts beyond around six months. This is where the monoclonal antibody, the passive vaccine or the provision of a preformed potent antibody against RSV is going to be an important tool that, again, is coming down the pike now, we hope will be available for this RSV season. And that's where a little bit older infants who are still in the first few months of life in RSV season will be eligible to receive it. If the infants are born during RSV season, they will also likely be eligible.

The eligibility criteria are still being reviewed now, but this is where we can start to bridge the gaps of immunity where we know children are still at risk. But then, we still have a need at the toddler age groups as well. I think this last year when really our children's hospitals were overwhelmed by the number of patients coming in with RSV and other respiratory illnesses, a lot of them were toddlers, two, three, four-year-olds even. And so, a toddler version of the vaccine is still working through trials now. I expect we will see something in the coming years that will include that older age group. But for now, we're so excited for our newborns and new parents that these tools to prevent RSV in your family are becoming available.

Melanie Cole, MS: Well, that is exciting. And thank you so much for telling us about bridging that gap and all the exciting advancements that are happening. It seems so quickly, but certainly so important for our kids. And Dr. Acker, for parents whose kids do come down with this, or flu or COVID at this point, what is some supportive care? What home care do you pediatricians recommend we do with our kids? Are we taking them in a steamed shower? Are we giving them Motrin or Tylenol? What are we doing for them?

Dr Karen Acker: Yeah. So, we do have multiple ways we can help our kids get through their RSV or other illness. Unfortunately, we don't have any specific antiviral or medication for RSV. But fortunately, for the most part, the symptoms can be relatively mild. So, some of the main things that I recommend and also even like to do for my own kids, one is that the nasal congestion I find is one of the worst parts of a mild RSV illness. You know, the nose is stuffed, they can't breathe. Especially infants, when their noses are stuffed, it makes it harder for them to feed and that's why even just dehydration can be an issue with infants with these viral illnesses. So, I often recommend, one, either a bulb suction or some kind of nasal suction. You know, there's different products where you can help kind of suck out the mucus from the nose, helps with that relief. Using a cold humidifier in their bedroom overnight, can help kind of loosen up the mucus. Those are the main things I recommend. Steam showers could offer a similar effect, but there's always the risk of a hot shower and with burns. So, I always have to have that disclaimer. And then, to treat fever and just the discomfort from a cold, you can give or acetaminophen. And once they're six months or older, then you can also offer ibuprofen as well. You don't have to treat the fever per se. It's not the fever that's an issue. It's more the discomfort you have around the fever. So, those are some things you can do just to kind of help your child get through their illness.

Of course, you also want to look out for when to bring them to the doctor, when to come to the emergency room. And the two main reasons that you would have to think about doing so is either dehydration or respiratory distress. And so, to identify dehydration, you're following how much your child is drinking. And with babies, really the main way is following how many wet diapers they have. So, the kind of golden rule is, you know, anywhere about five diapers in a 24-hour period tells you that they're hydrated enough.

In terms of respiratory distress, some things to look out for are faster breathing. If it seems like your child is breathing at a faster rate than normal, if you're seeing that chest tugging where you're seeing the outline of the ribs and chest pulling in at the neck at a fast pace, it tells you that your child is working harder than they should to breathe. And that's a reason to bring them into the emergency room or at least see their doctor right away.

Melanie Cole, MS: What an informative episode this is, doctors. You are both just so awesome. Dr. Permar, last word to you here. I'd like you to speak to parents now about RSV, the dangers that it does pose to our very littlest, most vulnerable sweeties and what you would like them to know about this upcoming vaccine, which is so exciting, and really anything you'd like them to know about vaccines in general and the importance of looking to our wonderful pediatricians if we have absolutely any questions at all.

Dr Sallie Permar: Exactly. That was what I was going to echo myself, is please talk to your physicians, your obstetricians if you're pregnant, your pediatricians for your newborns. But really, to say that so much care and effort has gone into the development of these vaccines. Really, we're talking decades of work, decades of pediatrician scientists who understood what an important pathogen this is and what an impact it has on those very first weeks of life in particular, which it's so disruptive if your family has to bring your child into care, bring your child to emergency room, bring your child into a hospital setting. And often, these RSV hospitalizations are not short. They end up being there for weeks on end. There are children who don't even make it in time to emergency room or hospitalization from these viruses as well. And so, it will be a different world, honestly, on the hospital wards for children in the wintertime if we can all use these effective vaccines in the way that they've been tested and shown to be effective and safe.

And so, we are looking forward to a day where we don't have to sit and watch children work hard to breathe and worry about whether you have to put a tube in their throat to help them breathe, worry about whether they'll develop a pneumonia that comes after the respiratory viral infection. That this is something that we absolutely know will have a major impact on improving the health of children, not only for the time that they're this young, but actually can even improve their lifelong health by reducing their chance of developing asthma as well. So, talk to your pediatricians and obstetricians if you have questions, but know that so many eyes have been on these vaccines and we are rooting for them to come through the process and be available to our families before the next respiratory viral season.

Melanie Cole, MS: Hear, hear! That was so well said. And parents, I just have to reiterate, our pediatricians, they are the ones. You can ask them anything. That's what they're there for. And as Dr. Permar said, you can also ask your obstetrician-gynecologist if you are someone that's pregnant. But that's what our pediatricians are really for and they help so much. So, please ask your pediatrician if you have any questions about the RSV vaccine or really anything having to do with our children. Thank you both so much for joining us today.

And Weill Cornell Medicine continues to see our patients in person as well as through video visits, and you can be confident of the safety of your appointments at Weill Cornell Medicine.

That concludes today's episode of Kids Health Cast. We'd like to invite our audience to download, subscribe, rate and review Kids Health Cast on Apple Podcasts, Spotify and Google Podcasts. And for more health tips, go to weillcornell.org and search podcasts. And don't forget to check out Back to Health, so many interesting podcasts there. I'm Melanie Cole. Thanks so much for joining us today.

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