What You Should Know About This RSV Surge

8:50 minutes

The lower third of a child's face is visible. Sick young boy, 3 years old, inhaling medication by inhalation mask to cure Respiratory Syncytial Virus (RSV) on hospital bed.
Credit: Shutterstock

Respiratory syncytial virus, known as RSV, is the number one cause of infant hospitalizations in the United States, and cases are soaring this year. Because young children have spent part—if not most—of their childhoods isolated, masking, or staying home due to the pandemic, many of their immune systems haven’t been exposed to RSV until now. It’s caused a huge surge in cases, and placed a heavy burden on pediatric clinics and hospitals. 

What do you need to know about the spike in infections? Ira talks with Dr. Carol Kao, a pediatrician and assistant professor at Washington University in St. Louis, Missouri, who has treated RSV for years. They dig into why this surge is happening now, the basics of the virus, how RSV is treated, and where we stand with an RSV vaccine.

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Segment Guests

Carol Kao

Dr. Carol Kao is a pediatrician and assistant professor at Washington University in St. Louis in St Louis, Missouri.

Segment Transcript

IRA FLATOW: We’ve been talking about hospitals and pediatric clinics inching towards maximum capacity as RSV surges among children. But how much do you really know about the virus? How did this surge even happen? How do we treat RSV? And the big question– where do we stand on a vaccine?

Here with RSV 101 is someone who treats it year after year, Dr. Carol Kao, a pediatrician and assistant professor at Washington University, in St. Louis. Dr. Kao, welcome to Science Friday.

CAROL KAO: Hi. Thanks so much for having me.

IRA FLATOW: Nice to have you. RSV isn’t a new virus, right? It’s been going around for decades. Why are we seeing such a big surge now?

CAROL KAO: Correct. RSV is a very old virus. It’s very common, typically causes mild cold-like symptoms, and almost everybody has had it by the time they’re two years of age. And as you may have seen in the news, we have had an unusually early and severe RSV season here in St. Louis, and also across the country. We think this is because of a lot of the social distancing measures that were implemented early in the COVID-19 pandemic. We saw virtually no RSV during the winter of 2020 to ’21. So many kids didn’t get exposed to it when they normally would have. This created this immunity gap.

And this year, with almost everybody back to in-person learning and social activities, we had a pool of kids whose immune systems hadn’t seen viruses, and it’s causing this increase in hospitalizations across the country.

IRA FLATOW: And how severe is it getting in these kids?

CAROL KAO: Yeah. So we have had an increase in five times of hospitalizations for RSV compared to this time last year. About half of the kids in our hospital are requiring intensive care units, or ICU, care. So we are definitely seeing just greater numbers and increased severity.

IRA FLATOW: Most kids are fine with it, correct?

CAROL KAO: Correct. You are absolutely correct. RSV is the number one cause of hospitalizations. But worldwide, it causes over 30 million infections in kids less than five years of age per year. And for the majority of those kids, it is a mild cold-like symptom, and they get over it like they do any other cold.

IRA FLATOW: So who is most at risk then?

CAROL KAO: Small infants, in particular, can get into a lot of trouble with RSV because of their small airways. So they can get plugged with mucus, and then that leads to trouble breathing and sometimes severe infections, such as pneumonia. They can also get into trouble if they get dehydrated. And they may need a little bit of intravenous fluids and help with their breathing to get them through.

IRA FLATOW: We’ve been talking about kids mostly now, but older people can get it, too, especially the elderly. And it may be difficult for them?

CAROL KAO: You are absolutely correct. We are increasingly understanding that RSV can definitely affect adults. And in particular, older adults can also get severe RSV, and are also at higher risk of getting RSV. It’s just that we don’t test them as much. So we don’t always know that that’s what they have. RSV can also cause severe infection in kids and adults with certain medical conditions, such as underlying heart or lung issues.

IRA FLATOW: Well, we’ve got a whole slew of viruses going around now, right, RSV, the flu, COVID. How do you know a kid or an adult has RSV and not something else?

CAROL KAO: There is not necessarily a telltale sign. However, if you know that there’s a lot of RSV in your community or that your kid’s classroom had an RSV exposure, then the odds are your kid’s symptoms are probably due to RSV.

Symptoms of RSV, COVID-19, flu, a bunch of other respiratory viruses are very similar. So the really only way to determine which virus is causing an infection is by using some sort of test. The majority of kids do recover on their own. And for RSV, there really are no specific treatments, so testing is not always necessary. Treatments for COVID-19 and influenza are available. So testing for those may potentially be beneficial.

IRA FLATOW: So there’s no real drug to take for RSV is what you’re saying?

CAROL KAO: Correct. Unfortunately, right now, all we can offer is supportive care, meaning supplemental oxygen or breathing support. Sometimes, if they’re really sick, kids may need a breathing tube. And really, we can only wait until they get better.

If parents aren’t sure whether their kid needs more help, they should definitely start with your pediatrician. However, if your kid is visibly having a lot of difficulty breathing, meaning that they’re struggling to breathe, they have a loud wheezing or very rapid breathing, or you just think they are not doing well, you should seek emergency help definitely. Because, again, kids can get into a lot of issues with RSV.

IRA FLATOW: This is Science Friday, from WNYC Studios.

I’m talking with pediatrician Dr. Carol Kao about where we stand with RSV. We know that RSV circulates every fall and winter. That’s not a surprise. But what is surprising to me is how we’ve gone this long without a vaccine, right? Where do we stand on getting an RSV vaccine?

CAROL KAO: In the 1960s, there was a vaccine that actually led to worse disease in babies due to an imbalanced immune response. And that really halted the RSV vaccine field for a very long time. Then, in 2013, researchers at the NIH made a very key discovery of the virus. And that really reinvigorated the whole RSV vaccine field. And so there are multiple RSV vaccines, therapeutics, antivirals, and long-acting monoclonal antibodies in development currently. They are in phase 2 and 3 trials.

Very recently, Pfizer announced preliminary results of their phase 3 study, looking at an RSV vaccine given to pregnant women. And it was found to be highly effective at preventing severe RSV in babies in the first six months of life. They did announce they plan to seek approval by the FDA at the end of this year. So we are hopeful vaccine will be available by next fall and that we’ll be seeing a very different RSV season next year.

IRA FLATOW: Are kids being used in these trials? And would that be one of the reasons why trials are taking so long?

CAROL KAO: That is a good question. There is studies of the vaccines given to children. But because we know RSV impacts infants the most, a lot of the vaccine trials are actually targeted towards pregnant women, to then generate immune response that can be passed on to the baby. And we see this strategy used for influenza, pertussis, and, most recently, COVID-19 vaccines.

IRA FLATOW: Interesting. One more thing before we go, Dr. Kao, let’s talk about what tips you have for how to stay RSV-free this season.

CAROL KAO: One of the best ways to keep you and your loved ones safe this winter is to make sure you get your flu vaccine this year and also that you’re up to date on your COVID-19 vaccines. I hear a lot of people say that the flu vaccine doesn’t work. But you put your seatbelt on when you get in your car even though it may not fully protect you from a severe accident. So why not get the flu and the COVID-19 vaccine shots, which have been shown to prevent you from being hospitalized and getting very, very sick?

Also, just very simple things you can do to prevent getting sick, like washing your hands, disinfecting frequently-touched surfaces, staying home when you’re not feeling well, masking if you have to go out, and then covering your coughs and sneezes in a tissue or the elbow of your shirt sleeve.

IRA FLATOW: Where have I heard all of this before? We should be primed for this by now, right?

CAROL KAO: Yes. You would think so. Yes.

IRA FLATOW: All right. Thank you very much for taking the time to talk with us today.

CAROL KAO: It was great to be on this. Thanks so much.

IRA FLATOW: You’re welcome. Dr. Carol Kao, a pediatrician and assistant professor at Washington University, in St. Louis, Missouri.

We have to take a break. And when we come back, the latest in mapping the human brain, and why understanding a network of connections is more important than identifying specific brain regions. New stuff. Stay with us.

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