⚕️The Hearts We Didn't Know We Were Breaking: What We're Learning About COVID's Long Shadow on Our Children

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We told ourselves a story about children and COVID-19. It was a comforting story.

Like most comforting stories we tell ourselves during crises, this one was both partially true and dangerously incomplete.

A massive new study from the RECOVER Consortium has just shattered our comfortable narrative. The kind of study that's too big to dismiss, too methodical to wave away, too urgent to ignore.

Lu Li et al, Kidney Function Following COVID-19 in Children and Adolescents, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.4129

Dazheng Zhang et al, Pediatric Gastrointestinal Tract Outcomes During the Postacute Phase of COVID-19, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2024.58366

Bingyu Zhang et al, Cardiovascular post-acute sequelae of SARS-CoV-2 in children and adolescents: cohort study using electronic health records, Nature Communications (2025). DOI: 10.1038/s41467-025-56284-0 

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Transcript

0:25

It really is striking how our view of COVID-19 keeps shifting, isn't it? At first for kids, all the worry was about, you know, the immediate sickness. But now, while it seems like the story doesn't quite end there, these longer term impacts are really coming into view. That's absolutely right. We're definitely looking much more closely now at what happens in the weeks and months after that initial infection in children, in adolescents. the potential for, well, lasting changes. And that's precisely what we're diving into today, this connection between having SARS-CoV-2 and cardiovascular issues in kids and teens, basically anyone under 21. Yeah. We've got a really important study here. It's from the Recover Consortium. using electronic health records from, what, 19 U.S. children's hospitals? That's right, a huge data set. And we'll pull in some context from medical news outlets, too, just to round things out. Okay, so our mission today, really understand this increased risk, the risk of various heart problems, blood vessel issues in this age group after COVID. And what's really crucial, I think, is that this study looks at everyone, kids with pre-existing heart conditions and those without. Right. That's important. Now we hear these terms thrown around long COVID, PASCSC. Can we just clarify what we mean when we talk about these lingering effects in this context? Sure. So PASCSC post-acute sequel A of SARS-CoV-2, that's Basically the umbrella term for health issues that stick around or pop up after the acute phase is over. Different groups like the WHO or NIH have slightly different time windows. WHO talks about three months post-infection. Yeah. Lasting at least two months. Okay. But this main study we're focusing on, they looked at cardiovascular outcomes happening between 28 and 179 days after that first positive test. It's a common time frame used in pediatric research for this post-acute window. Got it. And, you know, we've seen quite a bit about adult heart issues after COVID, but for kids, it feels like the picture's been a bit fuzzier, maybe focused on specific things like MIS-C or myocarditis. often with shorter follow-up. Exactly. That's why this RECOVER study is so significant. It casts a wider net looking at a broader range of cardiovascular outcomes and, crucially, following these kids for a decent amount of time, at least six months. Okay, so let's get to it. What did they find? What's the main takeaway from this massive study? The headline really is this. Kids and adolescents who had COVID showed a statistically significant increased risk. A higher risk of various cardiovascular outcomes compared to a carefully matched group of kids who hadn't been infected. And this wasn't just limited to children who already had a heart problem. It's such a critical point. No. The study found this elevated risk in both groups. those born with congenital heart defects, CHDs, and those who started with no known heart issues at all. Wow. That's quite something. Just give us a sense of the scale here. How big was this study? Oh, it's substantial. Really large cohorts. They analyzed data from nearly 300,000 kids, Two hundred and nine hundred and seven thousand nine hundred and twenty to be exact who tested positive. OK. And compared them to over nine hundred thousand controls who tested negative. And everyone was followed for at least six months. That's a huge number of kids. So how did they make sure they were comparing like with like? You know, the groups were similar to start with. Right. Good question. They used a statistical technique called propensity score stratification. OK. Fancy term. What does it mean? Basically, think of it as very careful matching. They matched individuals in the positive group with similar individuals in the negative group based on things like age, sex, race, ethnicity, even insurance type. Ah, so trying to level the playing field. Exactly. Yeah. To make the groups as comparable as possible. It really strengthens the idea that any differences they saw in heart outcomes are likely linked to the COVID infection itself, not just other underlying factors. Okay, that makes sense. So this overall increased risk is clear. Let's drill down a bit. What specific heart or blood vessel problems were popping up more often in the kids who'd had COVID? Yeah, the list is, well, it's concerning. They found significantly higher rates of several things. hypertension, that's high blood pressure. Ventricular arrhythmias, those are irregular heart rhythms starting in the bottom chambers of the heart. Myocarditis, which is inflammation of the heart muscle itself. Heart failure. Cardiomyopathy, which is a disease that weakens the heart muscle. Wow. And even cardiac arrest, though rarer. That's a really serious list. It is. And it didn't stop there. They also saw an increased risk of thromboembolism, blood clots. Right. Clots that can travel. Exactly. And also more reports of symptoms, things like chest pain and palpitations. Palpitations, like feeling your heart race or skip beats. Precisely. And beyond just listing these individual conditions, the researchers also grouped related issues together. They call them composite outcomes. Maybe categories of problems. Yeah, sort of. And these broader categories also showed increased risks in the group that had COVID. What kind of categories are we talking about? Well, there was a composite for any cardiovascular outcome. Then specific ones for arrhythmias in general for inflammatory heart disease like myocarditis. Another for other cardiac disorders, which included heart failure and cardiomyopathy. Also one for thrombotic disorders, the blood clots, and even composite just for those symptoms, the chest pain and palpitations. And was the risk increase? sort of the same across the board for all these different things, or did it vary? No, definitely varied. The magnitude of the increased risk wasn't uniform. Okay. So, for example, hypertension, high blood pressure. The relative risk, which compares the likelihood in the COVID group versus the non-COVID group, was about 1.5. So, like a 50% higher chance for both kids with and without existing heart issues. Correct. Roughly 1.5 for both the CHD and non-CHD groups. And for that composite of any cardiovascular event, the relative risk was about 1.63. Again, pretty similar in both groups. I feel quite a bit higher. Oh, absolutely. But then you look at something like inflammatory heart disease in the kids without prior heart defects. The relative risk there jumped to around 2.9, almost three times higher. Wow, nearly triple the risk for heart inflammation in previously healthy kids. kids. Exactly. It suggests maybe a particularly strong inflammatory reaction happening in some kids' hearts after infection. That is really interesting. Okay, so we have this overall picture, elevated risk for everyone, but some specific things jumping out. Were there other nuances? Did they find differences when they looked at, say, different subgroups? Yes, absolutely. They dug into that too. One thing, the absolute risk, just the baseline chance of having any cardiovascular issue after the study period... was higher in the kids with congenital heart defects to begin with. That makes sense. They're already more vulnerable. Right. That was true whether they had COVID or not. But the increase in risk after COVID was seen in both groups. Okay. Any other interesting subgroup findings? Well, one thing, cardiogenic shock. It's when the heart suddenly can't pump enough blood. Very serious. The relative risk was higher in the non-CHD group after COVID. Really? In the initially healthy kids? Yeah. But it's important to stress it was still a very rare event overall in both groups. Just the relative increase was higher there. Got it. What about things like age or how sick they were with COVID initially? Did that matter? Generally, the main finding of increased risk held up pretty consistently across different age groups, across racial and ethnic groups for boys and girls. Even obesity status didn't seem to erase the overall increased risk. And another interesting point, it didn't seem to matter much whether the child got infected during the Delta wave or the Omicron wave. The cardiovascular risks look similar. That's a bit different from some adult studies where differences were seen between variants. Okay, so a lot of consistency then. But you mentioned they did some deeper analysis, some sensitivity analyses. Did those turn up anything more specific? They did. And yeah, a few things stood out there. For instance, older kids, adolescents age 12 to 20, and school-aged kids 5 to 11 seem to have a higher risk of any cardiovascular outcome compared to the youngest group, the under fives. An age difference there. Interesting. It is. Any differences emerge in that deeper dive? Yes, some interesting kind of specific sex differences popped out. Females seem to have higher risks for developing hypertension, deep vein thrombosis, DVT, and maybe surprisingly cardiac arrest. Whereas males appeared more prone to things like premature atrial or ventricular contractions, those extra or skipped heartbeats. pulmonary embolism, and thromboflebitis, which is vein inflammation, often with a cut. That's quite a varied pattern depending on sex. And obesity, you said it didn't erase the overall risk, but did it play any specific role? It did seem to have a bit of a mixed role. Obesity was linked with increased risks for some of the really severe outcomes, like those ventricular arrhythmias. But interestingly, it was associated with a lower risk of just reporting symptoms, like chest pain or palpitations. Huh. Yeah. That's complex. It suggests maybe a more complicated interaction there that needs more looking into. And it feels intuitive that how sick you were initially with COVID would matter for long-term stuff, right? Absolutely. And the data bore that out. Kids who had severe acute COVID-19 maybe needed hospitalization. Yeah. They consistently showed higher risks across all those composite cardiovascular outcome categories compared to kids who just had a mild infection. Right. That makes sense. So, okay, we're seeing this clear link, COVID infection, then higher risk of various heart issues later on in kids. Why? What could be actually causing this? Any ideas on the mechanisms? Yeah, that's the million dollar question, isn't it? This study wasn't designed to pinpoint the exact biological reasons, but we can look at related research, like studies on long-term kidney effects after COVID in kids and see potential parallels. Okay, so what are the theories? Well, there are a few possibilities. Okay. One is direct damage. The virus itself might directly harm heart muscle cells or the lining of blood vessels. Another is inflammation. Maybe there's this persistent low-level inflammation that just doesn't shut off properly after the infection clears, and that affects the cardiovascular system. Like a lingering immune response. Exactly. Or it could even be indirect effects. The body's overall response to the virus, the stress it puts on the system, might trigger downstream cardiovascular problems. It's likely complex, maybe a mix of factors. There's still a lot to figure out biologically. Definitely. But I think the really strong signal from this study is the potential for a broad impact. Remember, even kids with absolutely no known heart problems beforehand show these increased risks. Yeah, that's key. It really underlines why we need to think about the long-term heart health of basically all kids who've had COVID. So practically speaking, what does this mean? What are the implications on the ground? Well, the study authors point to a couple of big things. First, healthcare systems probably need to think about resources, you know, planning for potentially more long term monitoring of cardiovascular health in kids and teens post COVID. Okay. And second, it's just crucial awareness. Doctors, nurses, other healthcare providers need to know about these potential increased risks. That way, if a child comes in with symptoms or even just for a checkup, they can think about this possibility, make timely referrals, get the right tests done, and manage any issues that pop up. Absolutely. Now, before we wrap this up, we should always look critically at the research itself. What were the big strengths of this study and maybe some limitations to keep in mind? mind. For sure. Strengths. Yeah. Definitely the size. Huge number of kids. Yeah. And the longitudinal follow-up, tracking them over time, that's really valuable. Also, using that propensity score stratification we talked about, that really helps make the comparison between the groups more robust. Right. Matching. And analyzing the CHD and non-CHD kids separately gives us vital information for both those populations. Big strengths. Okay. Sounds pretty solid. What about the flip side? Any limitations we need to consider? Yeah, like any study using electronic health records, there are always some inherent limitations. For example, it's possible some kids in the uninfected control group actually had COVID but were asymptomatic or just never got tested. That could dilute the findings a bit. Okay. Misclassification. Right. Right. And while they used good statistical methods to control for confounding factors, you can never account for absolutely everything in an observational study. There's also the issue that kids who had COVID might just have more doctor visits afterwards, meaning issues are more likely to be detected, sometimes called surveillance bias. Ah, okay. And finally, a couple of specifics. They didn't exclude kids whose congenital heart defects had been surgically corrected, which could influence outcomes. And they couldn't fully track things like reinfections or vaccinations that happened outside the hospital systems providing the data. So it's a really important piece of the puzzle, gives us strong signals, but maybe not the absolute final word yet. Exactly. It provides a very strong indication that vigilance is needed. We need to pay attention to kids' cardiovascular health after COVID. Okay. So let's try and bring this all together. What's the single most important message you want people listening today to take away? I think the core message is this. Having SARS-CoV-2 infection as a child or adolescent is linked to a real measurable increase in the risk of developing various cardiovascular problems in the months afterwards. Right. And crucially, this increased risk seems to apply whether or not the child had any heart condition beforehand. And why is this important for you listening right now? Well, it's vital knowledge for everyone involved, parents, caregivers, young people themselves as they get older, and definitely healthcare professionals. Right. Being aware of these potential long-term issues means symptoms might be recognized earlier. Leading to quicker help. Exactly. Timely medical attention, getting the right diagnosis, starting appropriate management if needed, that can make a real difference to long-term health. It also just reinforces that even if the initial COVID illness seems mild in a child... We can't just assume there are no potential longer term effects. Yeah, it really does feel like this research drives home the need for ongoing attention, doesn't it? More investigation into these long term impacts of COVID on our kids and teens. Absolutely. It clearly highlights that need for continued research to understand why this is happening better. And of course, to develop the best strategies for prevention, for monitoring for treatment down the line. So as we close out this discussion, here's something for you to think about. Knowing about this increased cardiovascular risk after COVID in kids, what kind of proactive steps, maybe even innovative ones, could we take to really protect their long-term heart health? And looking ahead, how might this growing understanding actually shape future public health advice or change the guidelines for pediatric care? Definitely easier thought. Thanks for exploring this with us today.