Dr Mike Smith (Host): Welcome to Pediatrics in Practice, A CME Podcast. I'm Dr. Mike, and joining me today is Dr. Maria Daisy Leon from Children's Mercy. We'll be discussing a critical topic in pediatric health RSV, in pediatrics, immunization strategies and treatment insights. Welcome to the show.

Dr Maria Deza-Leon: Hi. Thanks for having me.

Dr Mike Smith (Host): So what are the biggest challenges pediatricians are facing during RSV season and how have the trends shifted? Post pandemic.

Dr Maria Deza-Leon: As you probably know, RSV is the leading cause of bronchiolitis and pneumonia in infants, and it is the number one cause of hospitalizations in kids under two years of age. Causing about like 50 to 80,000 hospitalizations a year, all within that limited period that we called RSV season, which leads to overcrowding clinics and hospitals.

And this strain is felt everywhere throughout the healthcare system, but particularly in primary care settings, which often serve as. That first point of contact before hospitalization. And as most viral infections, there is no specific treatment other than supportive management, which can be very frustrating for parents that see their child is ill.

so these kids are often gonna need close follow up additional visits, and this can really be a challenge for pediatric offices. And after the pandemic started, there was this whole year there, there was no RSV, but then. Seasonality was completely disrupted with 2021, having a peak in the middle of the summer and 2022 having an early fall peak, which we were definitely not prepared for.

throughout the next couple of years, we have seen that it has gone back to its pre pandemic seasonality, but as much as we would love to predict how viruses will behave, we really can't. So we have to be prepared at all times, and that is definitely a challenge when it comes to RSV.

Dr Mike Smith (Host): Yeah. Meaning the viruses don't necessarily follow our schedule.

Dr Maria Deza-Leon: Yes, exactly.

Dr Mike Smith (Host): right, right. you said something there that, you know, with RSV, the treatment is really supportive for the most part. Right. Which means prevention's key, which brings us to vaccines. can you tell us a little bit, now there's a new vaccine out. How does that differ from the traditional, RSV vaccines?

Dr Maria Deza-Leon: So there's actually a couple of different, new immunization strategies. Two of them are NEV and Umab, which are a very similar product that, We're approved, one in 2023, the other one earlier this year, and are both monoclonal antibodies, so they're not technically vaccines in the traditional sense, but they provide passive administration, meaning they can confer long lasting protection from RSV through specific antibodies.

And this protection is expected to last at least five months, so around the length of a regular RSV season. And the wonderful thing about these antibodies is that they have excellent data for effectiveness. studies have shown reduction in severe disease of up to 80% in the trials, meaning less hospital admissions, less ICU stays if children acquire the infection.

And there's now real life data from multiple countries such as Chile, where Universal Vaccination with NEV was implemented, and some early data from the United States that have seen a dramatic decrease in RSV associated hospitalizations. So this has truly been game changing for pediatric health as we've all been marked by those BCU winter months with multiple admissions from bronchiolitis and kits that were gasping for air.

And those who benefit most from these interventions are gonna be children on their first RSV season as both monoclonals are approved for up to eight months of age for kids, for their first RSV season. And NEV is also approved for up to 19 months of age in a select group of higher risk patients for a second R RSV season.

Dr Mike Smith (Host): Okay. What's the current guidance on RSV vaccination during pregnancy and how does that impact infant protection?

Dr Maria Deza-Leon: current guidance is for moms to receive maternal RSV vaccine between weeks of gestation 32 to 36, just as moms are recommended to receive that TDAP vaccine to provide passive immunization through maternal antibody passage through the placenta. Same thing would happen with the maternal RSV vaccine, and it has also been proven to be quite effective with decreases on severe disease by almost 70%.

And current guidance only recommends the vaccine to be given once for a pregnancy. However, there are ongoing trials to evaluate a second dose in subsequent pregnancies. as well as evaluating how long lasting the immunity from that initial vaccine has been. So we're hopefully gonna have more data about this in the coming years.

And regarding its impact on infant protection strategies, it is very important to know if a mom received the maternal vaccine and when, as this may affect the baby's eligibility for a monoclonal antibody for that nev and umab that we were talking about. So we have to know in advance.

To allow for better planning. Now in the real world, pediatric offices will not really be part of pregnancy immunization guidance unless the parent of a current patient is expecting. So unless we are having early prenatal visits, guidance may be up to our ob gyn colleagues, which have been doing a wonderful job at offering this.

And if the mom has received the vaccine, but the baby was born before two weeks after getting the vaccine, then monoclonal antibodies are still recommended. As we don't know if there was enough time for those antibodies to cross the placenta. but if it's been more than two weeks since the mom got the, vaccine baby was born, then they do not need to get monoclonals as they should have acquired protection.

Dr Mike Smith (Host): Now for children who do develop severe RSV, the most effective treatment approaches today? And are there any emerging therapies on the horizon?

Dr Maria Deza-Leon: this is actually a very, exciting thing about RSV, therapeutics. as we have talked before, similar to many other viral infections, treatment for RSV is gonna be primarily supportive, so you might need to do airway clearance, some oxygen ventilation support when necessary. Along with having lots of patients as these infections are gonna be typically self-limiting.

and currently there are no approved antiviral drugs specifically for managing severe RSV infection. Rine is sometimes used in severe infections, but it's really expensive. It has some potential toxicity and it has very limited efficacy that has been proven. So we don't really support its routine use. But there are several investigational agents that target RSV and are in various stages of clinical trials.

There's one that's called ZA Reservoir that already has a phase three data suggesting that it has very good efficacy and a very favorable safety profile. it has not yet been approved for a widespread use, but I think that's getting closed. But even once antivirals become available, their greatest benefit happens when they're administered very early in the course.

So this reinforced that prevention is still gonna be our most effective strategy.

Dr Mike Smith (Host): You know, in many households today, you will often find young children with either older parents or grandparents, you know, people say 60 or over all living together. how much of a problem is household transmission?

Dr Maria Deza-Leon: It is actually pretty big. most studies suggest that transmission happens from younger patients to adults, so children are gonna be main infectious vector for RSV. so hopefully by implementing. These immunization strategies, we can decrease the amount of RSV that gets transmitted in households. Now, there's also a vaccine that's available for adults that are older than 60 years of age and.

This is available because even though when we hear RSV, we think mostly of kids with bronchiolitis. However, older adults, especially those that have comorbidities, are gonna be at higher risk of developing severe RSV infection that can lead to hospitalizations. and this vaccine has actually been approved, and it shows 70% efficacy against RSV related acute respiratory illness, which is huge.

So if we can get all grandparents and all the babies immunized for RSV, who are gonna be the people at highest risk, then our transmission is gonna decrease significantly.

Dr Mike Smith (Host): I'm gonna make sure I heard this right. did you say a 70% reduction in severe RSV for that older population?

Dr Maria Deza-Leon: Yeah.

Dr Mike Smith (Host): Yeah. Okay. Let's get everybody vaccinated. Right.

Dr Maria Deza-Leon: absolutely, absolutely. It's really impressive. these interventions have been game changing.

Dr Mike Smith (Host): Okay. So obviously immunization strategies are, key. even though there's some, treatments in the horizon, all that stuff, that's great. It's still always easier to prevent. Right? And that's, I. Exactly what we do with immunization. so here's the tough question now, what advice do you have for pediatricians who are trying to navigate the supply of these uh, medicines, the timing, even insurance coverage for these immunization products?

Because I know that has to be a headache.

Dr Maria Deza-Leon: Absolutely, and this can be quite tricky 'cause we went from having no preventive options. To now having three approved choices with a few more down the pipeline. So it's gonna become a nightmare for every pediatric office. and this is an absolutely positive shift that provides alternatives in case of any shortages, which we have experienced in the past.

When Nev Map first came out, there was a lot of issues with supply, so having multiple options is really a great thing. But logistics are gonna be very difficult to manage for pediatric offices. another thing that can be a bit of a headache is that, for example, for NEV Map, there are two different formulations available.

One that's a 50 milligram dose and another one that's a hundred milligram dose. And it depends on whether the child weighs less or more than five kilos. So you need to carry two separate formulations and unfortunately. It would be great if you could just carry the 50 milligram and you could give two doses, but insurance will not cover that.

or if you could do the a hundred milligram and just use half of it, but unfortunately that is not an option either.

Dr Mike Smith (Host): From the insurance standpoint,

Dr Maria Deza-Leon: yes, from the insurance standpoint, but the a hundred milligram dose, you cannot actually divide it. So it's difficult for pediatric offices. Basically have to make sure that they carry all formulations available

Dr Mike Smith (Host): Yeah. You have to have a nice inventory of it.

Dr Maria Deza-Leon: Exactly. for these other, monoclonal antibody that has recently come out, umab, it doesn't have a weight-based restriction, so you can give the same dosing for kids of all weights. The only problem is that you cannot give it for children that are older than eight months. So it might be difficult to decide which one you want to stock in your office, and this takes very careful consideration of your practices patient population.

Dr Mike Smith (Host): Now we know RSV does follow some seasonal aspect right to it. Although you did mention it's kind of all over the place here and there. We've been surprised. But with that said, I, is it best to go ahead and stock up during the season of RSV or do you think it's best just to have a supply all the time?

Dr Maria Deza-Leon: Right now the guidance is to give the immunizations only for the SV season. So if you wanna have it throughout the whole year, it can be helpful If we start seeing changes in seasonality, Pretty sure. I would be hopeful that if that were to happen, that insurance would be able to cover all of these, but because of how insurance works right now, offices are only recommended to provide the monoclonal antibodies during this specific timing.

Dr Mike Smith (Host): Gotcha. And so that's obviously when you need to be ready, have your supply. and follow that scheduling, this has been fantastic, any last words for the listening audience about RSV, about immunization strategies and even what may be coming down the line in, treatment.

Dr Maria Deza-Leon: I had to say that one of the things I am most excited about right now is how the success of these RZ prevention strategies has really opened up the door for broader innovation, and we're starting to see series investment in other preventive approaches for respiratory viruses like human met Pneumo virus and parainfluenza.

Which along with RSV are some of the major culprits behind bronchiolitis and cruin kits. There's an ongoing study of combination monoclonal antibodies that would target multiple viruses at once. So imagine just like you have NEV and TRO right now, you could give one that would cover RSV would cover human meum.

Avir could cover para flu. And as a parent who's experienced the stress of a child hospitalized with severe group, and as a pediatrician who has seen this infections causing life-threatening disease in my patients, I can tell you this is truly personal to me too, and it's incredibly exciting to think about what these breakthroughs could mean for families in the near future.

Dr Mike Smith (Host): Yeah. Fantastic. This has been great. Thank you so much for coming on the show and sharing all of your expertise. For more information, please visit C MKC Link. Forward slash CME podcast. If you enjoyed this podcast, remember to share it on your social channels and explore our entire library of topics that are of interest to you.

This is Pediatrics in Practice, A CME podcast. I'm Dr. Mike. Thanks for listening.