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In recent weeks, I’ve been responding to some rumors around mRNA vaccination and cardiac risks. One of the allegations I’ve heard a few times is that the pro-vaccine crowd is “trying to normalize heart problems.” The implication being that heart problems weren’t a big deal before the COVID vaccine, yet have now spiked because of it.

When I hear this, I’m always a little surprised. I am one of tens of millions of Americans who live with a cardiovascular condition. In fact, they run through my family. My dad has a genetic condition called hypertrophic cardiomyopathy, meaning your heart is enlarged. I live with a rarer condition called a CPAM which affects your heart and lungs.

Both of us know these conditions come with risks. I’m young and very fit (used to be an ultramarathon runner), but I still have to be wary of chest pains. And this made me worried about getting boosted for COVID. I have a health condition so I could use the protection, but I also worried: “My heart is already dilated. What would happen if it were inflamed too?”

This question has pushed me to think deeply about mRNA vaccines and the heart. Over the past few months, I reached out to a number of cardiac specialists. What they said helped me feel much more confident in vaccine safety, and honestly made me take my own heart health more seriously. So I want to clear up a few rumors I’ve been seeing on social media in the past few weeks.

This is important because 121.5 million Americans have some form of cardiovascular risk factor. If we attribute heart problems to the vaccine instead of one of the most common contributors to morbidity and mortality, we will miss out on opportunities to help people with manageable conditions.

Myth 1: The Media is Trying to ‘Normalize’ Heart Conditions

Last week, someone posted a viral thread to Twitter composed of a series of recent headlines about risk factors for heart disease. One reads: Harsh winter can increase heart-related complications (December 6th), another reads Lonely older women at greater risk of heart attack (February 17th). Most relevant to me–and faithful to my experience–is Yes, even runners (and triathletes) get heart disease (February 11th). All of these headlines are predicated on actual studies, but what the author is alleging is a coordinated media blitz to hide the fact that COVID vaccines are causing heart attacks.

In TV shows and movies, people often thread random events to create a narrative. However amusing, be weary of those who do it in real life.


As someone who has worked in communications for years, I’ve written these kinds of click-driven headlines and can tell you the explanation is benign (basically capitalism). But benign explanations don’t drive social media engagement. So UK doctor Dr. Aseem Malhotra chose to inspire fear in his 182,000 followers: “I’m a cardiologist with over 20 years experience…Most of [these] headlines are BS. Either coincidental or deliberate distraction from the real cause.”

This is not a meaningful application of expertise. Malhotra makes no attempt to analyze how many headlines were published, if this is more than normal for this time of year, and if that even means anything. Most effective websites do search engine research on a weekly basis and frankly I wouldn’t be surprised if his followers googling ‘vaccine heart attack 😱’ was itself influencing publishers. 

That said, many of the headlines he references are backed up by data from before the pandemic. For example, this 2010 paper links cold weather to heart attacks (both a result of the cold itself as well as shoveling snow, which for many people is quite a bit of exercise). But what’s more concerning is Malhotra’s glossing over the fact that heart conditions are the subject of so many studies and articles because they are so incredibly common. A cardiologist who refuses to tell you this is not educating.

To that point, I looked through the CDC’s death certificate data from 1999 to 2021. The data list the underlying cause of death (what really killed a person). They tell us that at least 19% of all deaths in the United States in the last 22 years were attributable to a cardiovascular condition. That amounts to 10,500,000 million people and it is almost certainly an undercount because I just chose the top twenty or so causes. They include atherosclerotic heart disease, acute myocardial infarction, congestive heart failure, etc. These conditions are often related but for reporting purposes they come up separately.

A list of the top causes of death in the United States.  Those marked with a red dot are related to heart disease.


Mind you, these are just the deaths. Only about 12% of heart attacks are fatal, and we end up with 800,000 in the US alone every year. 600,000 of these are first time heart attacks, which due to low health literacy may be the first time a person realizes they are at risk. More to the point: heart disease is so common that if you followed 10 million people who had just been vaccinated, 2600 would have a heart attack within two months (based on pre-pandemic statistics).

That’s not all. There is another, particularly severe illness of the heart called sudden cardiac death. It’s different from a heart attack in that it involves an arrhythmia (problem with beating) rather than a blockage of arteries. Sudden cardiac death (SCD) claims the lives of 325,000 adults each year, making it the #1 natural cause of death. Sadly, 7,000 children also die from SCD each year and for them it typically happens within minutes. Half have no symptoms beforehand.

Candace Owens is unaware that hundreds of thousands of people die suddenly every year.


If you find this fact upsetting, so does everyone else. It’s the reason there are defibrillators in so many public places despite their costing upwards of $900. Most people will almost never see them used yet we make such a huge investment. Most people will also never perform CPR (which can help in the event of SCD) despite 54% of people saying they know how. We invest an immense amount of time and money into fighting this condition.

And going back to where we started, it is because these deaths are so striking that we see news articles on heart disease all the time. People want to know and manage their risk, which is a good thing! Anyone claiming these articles are false is undermining awareness and hurting public health.

Some people try to deny this in a more numerical way. They throw a random point estimate at you, find some compelling graph from a faraway place or play with stats to manufacture a problem. The fatal flaw of every such tactic is that they are well past outdated. We have an irrefutable form of evidence that gives us relative numeric precision: electronic health monitoring. 

Several massive studies have now been conducted where researchers ask hundreds of hospitals as well as insurers for their digitized health records, and then examine outcomes in the vaccinated and unvaccinated. These studies are foolproof because they source data from an enormous number of disconnected doctors, and we know what happened to each of their patients.

One study, run by Doctor Nicola Klein, examined electronic data for 3.6% of the entire U.S. population. Klein is a trustworthy source because she herself helped to retract the MMRV vaccine, and she scrutinized this data in a careful way. First: she compared symptoms among the vaccinated 1-21 days after vaccination, and 22-42 days after vaccination. Because you would expect the effects to be front-loaded, if we’re not seeing more harm in the first 21 days, we probably just aren’t seeing many harms. To give an analogy: you wouldn’t expect a snakebite to have evenly distributed effects for 42 days after it happens. If you do, that just means the snake wasn’t venomous. 

The Red Bellied Snake, which isn’t venomous!


The only statistically significant adverse event Klein detected was myocarditis, which is already a known AE in young boys (occurred in this study at a rate of about 1/13,000). Cardiologists tell us that the benefits of the vaccine outweigh the risks for this age group.

Notably, Klein also did a comparison between the vaccinated and the unvaccinated by matching pairs of demographically similar individuals (e.g. 26M vaccinated and 25M unvaccinated). Once again: myocarditis was the only adverse event detected.

I’ll add onto this one more study of Israel which used similar methods yet encapsulated 19.1% of the country’s population. It found a slightly increased risk of myocarditis and pericarditis (both of which were much more commonly detected after infection), but no signal for heart attack. I’ve included a visualization of the data below.


To be clear, these data cannot tell us the exact rate of any one adverse event (they’re rare, so this requires a meta-review of studies). But what they can tell us decisively is that there isn’t some big heart attack risk we’re missing with the vaccines. Whoever says otherwise quite literally has to claim that thousands of regular doctors in health systems around the world are colluding to cover-up side effects. 

This is an indefensible claim, so instead they stick to cherry picking headlines or claiming that every otherwise healthy person who dies of heart disease was killed by a vaccine. They did it just last week when an athlete the year below me at Stanford passed away suddenly. I found myself feeling sick that I had to distract from this tragedy by correcting anti-vaxxers who rushed to it like ants. She hadn’t even passed from a heart attack.

Given that heart disease causes 1 in 5 deaths – and it’s one of the most striking causes – you will always be able to connect random dots to scare people. But please be better than that. It’s offensive to those who are grieving and contributes to harmful scientific illiteracy.

Myth 2: Coroner’s Reports Show the Vaccine is a Killer

Unfortunately, there is a newer and more complicated rumor about mRNA vaccines going around. Most of us who follow vaccine safety monitoring could easily dispatch Myth 1. Yet this second claim was actually sent to me by a non-cardiac doctor and it freaked a lot of people out. I bring it up after a simpler myth to show some continuity between the two in terms of how they propagate. We’re all vulnerable to misinformation. So what happened?

On Valentine’s Day, three pathologists published a case report of two young boys who had passed away in their sleep due to heart issues. The report was titled: “Autopsy Histopathologic Cardiac Findings in Two Adolescents Following the Second COVID-19 Vaccine Dose.” And basically within it, the authors propose that these two boys–one from Michigan, the other from Connecticut–died taking the vaccine. What was especially frightening was that the autopsy findings looked really strange, suggesting an adrenaline surge had suddenly killed them. The deaths came just 3 and 4 days after vaccination and neither had any prior cardiac symptoms.

Upon seeing this report many took to social media and disseminated it widely. I believe the initial source was a relatively mainstream doctor who called it a revealing report, yet gave little context. It then made its way into anti-vaccine circles and showed up on the conspiracy blog The Defender four days later, under the headline Autopsies Show: Vaccinating Teens for COVID Is Literally ‘Heartbreaking.’

Of course, you don’t have to be anti-vaccine to be worried by these findings. The report raises legitimate concerns. But the real problem in this story is how people reacted, failing to do their homework and thus leaving people less, not more informed.

I did my homework. The morning this report came out, I contacted two cardiologists for comment. One is a pediatric cardiologist who contributed to some of the pioneering clinical research on vaccine myocarditis. The other is a molecular cardiologist who has spent much of the pandemic addressing vaccine-related heart concerns. They both drafted responses independent of one another, and both were extremely skeptical. I also called the cardiologist on the coroner’s team and she clarified what could be implied from the report. Finally, I asked Dr. Paul Offit in my interview with him last Friday what his thoughts were. In every case, I came out with a much different story than the one circulating on social media.

Paul Offit and I on Zoom. Full disclosure: Paul is on our steering committee.


None of this took me much effort, and I’m a 23 year old who studied anthropology. A little research should be the bare minimum for doctors with tens of thousands followers who decide to share such reports. I wouldn’t call those who don’t anti-vaccine, but I do see similarities between this behavior and those sharing scary headlines without context.

What did the cardiologists say?

Most importantly, both of these boys had pre-existing heart problems. One of them had the condition I referenced at the beginning of this article: hypertrophic cardiomyopathy (an enlarged heart). We know this was not caused by the vaccine because hypertrophy is a significant physiological change that takes a long time to develop. It is, however, a leading cause of death in young people. Glen Pyle  writes: “The fact that a young person with a hypertrophied heart or one with fibrosis would experience sudden cardiac death is not surprising. These links are well established & don’t require a vaccine to create a connection.”

He also comments on the authors’ hypothesis that an adrenaline surge killed the two boys. This would precipitate a condition called Takotsubo Cardiomyopathy. Glen points out that this condition almost always occurs in women (90%), and 80% of them are over the age of 50 with the mean age being 70. It is also rapid-onset, damaging the heart within minutes. This all leads Glen to doubt that it would have killed two young over the course of 3+ days: “To say the connection is a stretch is an understatement.”

Frank Han comes to a similar conclusion, using what seems like common sense: “While it is possible this is catecholamine-induced, what the general public might not know is that we give catecholamines such as epinephrine to heart surgery patients nearly all the time to support heart function, sometimes for several days, and the recipients do not all go on to develop stress cardiomyopathy” (emphasis mine).

He also comments on the fibrosis seen in the second boy. Fibrosis is when heart tissue dies and new replacement tissue grows in its place. This remodeling of the heart generally makes it more susceptible to disease because the scar tissue cannot help pump blood. And while problematic, there are actually a huge number of potential causes: “genetic[s], myocarditis or some other process entirely such as an inborn error of metabolism. There’s also many viruses that could have been bad actors here. Any of these processes could have caused a fatal heart rhythm problem that ultimately killed these children. None of these processes require vaccinations to take place” (emphasis mine).

This is similar to what Paul Offit told me: “I would like to have seen a much more thorough exam by those coroners…ruling out that there had been any exposure for toxins or parasites or viruses or bacteria.”

In neither case did the coroners examine the heart’s conduction system, which would have helped to determine if the cause of death was an arrhythmia. 

To get even more insight, I reached out to Doctor Emily Duncanson who was the cardiac pathologist on the coroner’s report. She was crystal clear in our phone conversation that the intent of the report was not to dissuade pediatric vaccination. She noted that the connection between the vaccine and the deaths was not definitive, though she only provided the evaluation for the report and didn’t declare the cause of death. Emily also brought up the fact that we don’t have family histories for either boy. So her message was reassuring: “This is just two data points and we shouldn’t draw hard and fast conclusions.”

For one more piece of evidence, linked here is a clip where I ask Dr. Paul Offit–leading vaccine scientist and pediatrician–about the report. He was personally unconvinced by the findings, and brought things back to a basic point: “There are always going to be those temporal associations, the question is are they causal associations. I didn’t feel that report of two children in any way addressed that” (emphasis mine).

I think the reason people jumped on this report is because it sounds definitive. After all: the coroners physically examined the bodies for proof. But the reality is that in situations of ambiguity–such as commenting on a supposedly entirely new cause and mechanism of death–there is a heavy element of subjectivity. The CDC’s Cause of Death Handbook makes this abundantly clear: “The cause-of-death section is designed to elicit the opinion of the medical certifier…Causes of death on the death certificate represent a medical opinion that might vary among individual medical-legal officers…The cause-of-death section [is] always a medical opinion” (emphasis mine).

Given that the authors of the report we’re focusing on explicitly leave open the possibility that arrhythmia resulted from fibrosis, we should be clear that there remains uncertainty here. 

From the coroner’s report. Courtesy Glen Pyle.


As I noted here, I absolutely think we should further explore the issue and it’s possible these boys did die from the vaccine. It would accord with some exceptionally rare cases of deaths from vaccine-related myocarditis (though there are perhaps less than 10 in the world). But this specific case is so different, and so hard to discern causality within, that we can’t really take much away from it.

I’ve found other cases to which this applies: cases where people could have been more cautious. For instance, here is Dr. Tracy Hoeg sharing news coverage of a coroner’s report, claiming it is a confirmed vaccine death.


This was shared thousands of times. But when you actually look into the article the evidence is dubious. We just have audio of someone who for all we know is a coroner saying this death was vaccine-related. It’s suspicious because he also claims to be investigating several other vaccine-related deaths (and can’t even pronounce myocarditis). Given that vaccine myocarditis deaths are incredibly rare as accounted for by basically every study of the condition–including those using electronic records–there is next to no chance this is accurate within a single county. And since we don’t have any other evidence to go off besides this clip, it’s really not fair to say this is a ‘confirmed’ vaccine death.

I would thus urge you to be cautious in examining sources which share this kind of info. It gets retweeted endlessly by people who don’t know how to interpret the findings, and perhaps even by medical professionals who aren’t looking too closely. I don’t think Dr. Hoeg is at all anti-vaccine (and she makes some good points). But I also don’t understand why a doctor would create uncertainty during a pandemic when parents urgently need to make a decision.

Myth 3: Vaccines Will Produce a Future Spike in Heart Attacks

That said, there is one last myth that has perhaps generated the most uncertainty of all. It’s this idea that, even if the vaccine isn’t killing people just yet, it is quietly weakening our hearts and will lead to future health catastrophes. Here’s an example: I often talk about vaccination and heart safety on social media, and not long ago, someone responded cynically: “You’d better get yourself a cardiologist…” Their implication is that the vaccine has left my heart permanently damaged.

I’m so scared.


Frankly I hear this all the time. So where did this idea come from?

Back in November 2021, a certain Doctor Steven Gundry published an abstract in the journal Circulation. Circulation is a journal run by the American Heart Association, and the abstract was titled: “Mrna COVID Vaccines Dramatically Increase Endothelial Inflammatory Markers and ACS Risk as Measured by the PULS Cardiac Test: a Warning.”

The PULS test is a non-standard measure of cardiac risk which looks at a few different biomarkers and tries to predict who will suffer from heart disease in the future. What Steven Gundry did was look at a population of 566 people who had previously had a test and were slated to have another sometime after they received an mRNA vaccine. He did not include a control group, we literally don’t have the report, and he did not even attempt statistical analysis: “No statistical comparison was done in this observational study.” 

What Gundry tells us is that among participants, three of nine biomarkers showed increased values (with pretty wide margins of error). He then uses the PULS to predict that this increases heart attack risk in that population from 11% to 25% over the next five years, “[sic] based on data which has not been validated in this population.” 

If that sounds non-specific, it is. It basically tells us nothing. But that didn’t stop our dear friend Aseem Mahlotra from tweeting: “Extraordinary, disturbing, upsetting. We now have evidence of a plausible biological mechanism of how mRNA vaccines may be contributing to increased cardiac events.” In fact, he went onto the large British news channel GB News the next day which featured him speaking over the tagline Heart Attack Warning. And ever since, I’m still being told I am going to die of a heart attack.

Fortunately he’s wrong. The most straightforward way to respond is to say that Gundry’s abstract is exceptionally low quality evidence. For one, an abstract has very lax peer review, and given that this was an abstract for a poster presentation at a conference, it probably didn’t face real scrutiny. Frank Han notes that: “An abstract can be created by anyone who wants to introduce their research project, and it has the lowest peer review requirement.” 

Science writer David Gorski takes this a step further: “poster presentations are the lowest form of scientific publishing, reserved for the vast majority of abstracts submitted to major scientific conferences” (emphasis mine).

Another thing to note is that this abstract was considered so flawed that the journal hosting it issued a statement of concern. The American Heart Association points out that: “there are no statistical analyses for significance provided, and the author is not clear that only anecdotal data was used.” So we have no clue whether this correlation is significant, or if it can generalize to other populations.

That all said, the truly damning problem is that this test is not validated for vaccination. It is common sense that vaccines would generate some short-term inflammation since they affect your immune system, and “if you run a test designed to search for inflammation, after a procedure designed to generate temporary inflammation, you will find inflammation.” It’s entirely possible this test would turn up similar results for other vaccines which are actually known to decrease your risk of a heart attack. Clinical validation is a stringent process designed to make a tool useful in a specific context. We have no way of knowing what these results mean – if anything – because they misapply the PULS test.

If it eases your mind any further, there are millions of people like me in clinical registries designed to monitor the course of disease. Cardiac registries are by far the largest and most populated, and there are plenty of people essentially ready to have a heart attack. If the vaccine was suddenly inflaming a bunch of people’s hearts, my assumption is that a good deal many of us would drop dead or become ill. And trust me: no one worries more actively about their health than someone with a bonafide heart condition. We would tell you if this was happening.


Another fact I learned in the course of this applies to non-conspiratorial allegations against the vaccine. And that is: when looking at cardiac risk, the full clinical picture tells you a lot more than some numbers on a page. This is most relevant when we discuss vaccine myocarditis, which is a real and significant problem. The reason we vaccinate is that COVID also causes severe outcomes like MIS-C which outweigh the risks. MIS-C is by far a worse condition, at least in the hospital, and most doctors take its initial severity to indicate a worse long-term prognosis. But what some people do is point out a single elevated enzyme or indicator in myocarditis patients and hyperfixate on that. I have yet to meet a cardiologist who thinks this is appropriate. 

To quote Glen Pyle: “You have to look at the big picture. I could have a headache because I am mildly dehydrated or even stressed, or it could be a brain tumor…[Likewise,] cardiac hypertrophy is a sign of heart failure and exercise. An enlarged heart could be the product of training or disease.”

It is thus often more of a scare tactic to point to out-of-context biomarkers or symptoms than something which actually improves our understanding of health outcomes. There are valid ways to do it, but there are many invalid ones.

Heart-related Problems are Common

Finally, we’ve reached the end of this inquiry. If there’s one thing I want to come back to, it’s that heart problems are common. The scary truth doesn’t require vaccine harms: sadly, we all know people who will die of a heart-related cause in the next few years. For hundreds of thousands of Americans that just happened to be during the pandemic. A sizable number will have happened after vaccination.

The more positive takeaway is that because this is the most common cause of death, we have a lot of room leftover for prevention. We could see this happening and educate ourselves on the causes, warning signs and interventions which could still save tens of thousands of lives each year. But we become less able to recognize and address this problem if we choose to believe the vaccine is to blame when it is not.

Doctors who invent false causes for cardiac deaths reduce our awareness as a society and may ultimately cause harm. It is ironic and a bit sad that it’s up to people like me–those actually affected by cardiac conditions–to push back against them.

Noah Louis-Ferdinand is the Communications Coordinator at Voices for Vaccines.

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