- Health
Nature Biotechnology study misrepresented in social media posts claiming “all mRNA jabs cause heart damage”
Key takeaway
Like all medical interventions, COVID-19 vaccines can cause side effects. Myocarditis is a known side effect of COVID-19 mRNA vaccines, but is relatively uncommon. Scientific evidence shows that COVID-19 itself is more likely to lead to myocarditis and a host of other health problems compared to COVID-19 mRNA vaccination. Therefore, the benefits of the COVID-19 vaccines outweigh their risk.
Reviewed content
Verdict:
Claim:
Nature study shows “all mRNA jabs cause heart damage”
Verdict detail
Misrepresents source: The Nature Biotechnology study cited to support this claim didn’t demonstrate that mRNA vaccines cause heart damage. The study was designed to evaluate a novel method for detecting nanoparticles in preclinical studies, not vaccine safety. The experiments were conducted only in mice, and so cannot be extrapolated to humans. It also didn’t evaluate heart damage in its animal studies.
Full Claim
Nature study shows “all mRNA jabs cause heart damage”; COVID-19 vaccines should “never have been allowed to be injected into humans and should be immediately pulled from the market, based on these findings”
Review
In January 2025, Facebook posts appeared claiming that a study published in January 2025 showed “all mRNA jabs cause heart damage” and that COVID-19 vaccines “should never have been allowed to be injected into humans”. Examples of such posts can be seen here, here, here, and here. Collectively, these posts were shared more than 8,600 times. One of these posts was published by the Facebook page Global Freedom Fighters, which has more than 60,000 followers.
Three of the four posts we found contained identical text. We found the same text posted on X by the account @toobaffled, which currently has more than 208,000 followers. Given the timing of the X post (15 January 2025), this could be the post that the Facebook posts copied. The account also used the hashtag #diedsuddenly in its bio, a dog whistle implying that COVID-19 vaccines have caused a swath of sudden deaths across the globe. Science Feedback tackled this claim in earlier reviews and found it to be baseless.
The X and Facebook posts cited a Nature Biotechnology study, which was published in January 2025, to support its claims[1].
Science Feedback reached out to Ali Ertürk, a professor at the Ludwig-Maximilian-Universität Munich and one of the study’s senior authors, to better understand the study and evaluate the credibility of the claims made in the X and Facebook posts.
What did the study do and what did it find?
There is significant research interest in the potential therapeutic applications of nanoparticles. For example, they can be used as vehicles to direct therapeutic compounds to specific cells in the human body. One notable application of nanoparticles is in cancer treatment. Conventional chemotherapy tends to be relatively indiscriminate, leading to collateral damage of healthy cells, producing side effects like nausea, vomiting, and hair loss. Targeted drug delivery would mitigate these side effects.
In the Nature Biotechnology study, researchers developed an AI-powered method of detecting nanoparticle biodistribution in the body. This method is called Single Cell Precision Nanocarrier Identification or SCP-Nano for short.
In an email, Ertürk stated that the main goal behind this research was to develop a tool for preclinical studies (cell and animal studies) that could enable the development of more precisely targeted nanoparticle-based therapies. By allowing scientists to pinpoint where experimental materials, like a drug candidate, end up in the body during laboratory testing, SCP-Nano would equip scientists with better information to develop safer and more effective therapies.
“Currently, no other technology is capable of evaluating nanocarrier distribution and interaction at the single-cell level across whole organisms,” said Ertürk.
In the study, the researchers used lipid nanoparticles (LNPs) carrying SARS-CoV-2 spike mRNA to evaluate the performance of SCP-Nano. The same LNP technology was also used in COVID-19 mRNA vaccines. This is likely why the X and Facebook posts linked the study to COVID-19 mRNA vaccines, even though the study wasn’t designed to study vaccines.
Ertürk clarified that the LNPs used in the experiments were “early prototypes generated in [the] lab” and aren’t comparable to those used in mRNA vaccines. The study itself noted that the researchers “used laboratory-produced LNP and mRNA spike formulations, which differ from approved Good Manufacturing Practice (GMP) facility-produced LNP-mRNA vaccines”. This difference is important, because GMP ensures that a medical product meets a sufficiently high standard for safe use in humans.
Study wasn’t designed to evaluate vaccine safety or the effects of mRNA vaccines in the human body
Ertürk refuted the posts’ allegations, stating that “claims linking our work to vaccine safety or heart damage are a serious misrepresentation of our scientific research”.
There are several reasons why. Firstly, the study was designed to evaluate the utility of a novel method for detecting nanoparticles, not to evaluate vaccine safety or to make general claims about mRNA therapy.
Secondly, the study was conducted in mice, not humans. “Results from animal models cannot be directly extrapolated to human clinical outcomes,” Ertürk said.
Thirdly, as mentioned earlier, the lipid nanoparticles used in the study aren’t the same as the ones used in mRNA vaccines. They were generated in a laboratory and are different from vaccine LNPs, which are produced according to GMP.
Finally, while the study did observe nanocarrier uptake in the heart in mice, Ertürk clarified that “we did not investigate immune responses, inflammation, myocarditis, or circulatory damage related to mRNA vaccines”. No experiment in the study was related to vaccine-induced heart damage. “Our study focuses on imaging nanocarrier biodistribution and does not assess any pathological effects in humans,” he said.
False claims that LNPs in the COVID-19 mRNA vaccines accumulate in various organs and are responsible for health problems aren’t new, as previous reviews from Science Feedback show. Our reviews explained how such claims are misleading and that biodistribution data from animal studies show that while a fraction of LNPs reach certain organs, the majority of LNPs remain at the injection site. There’s no evidence that the comparatively minute quantities of LNP that reach other tissues in the body cause health problems.
Myocarditis (inflammation of the heart muscle) is recognized as a side effect of COVID-19 mRNA vaccines, although it is relatively uncommon. It’s important to note that the risk of health problems associated with COVID-19, including myocarditis, is greater than that associated with the COVID-19 mRNA vaccines[2].
Conclusion
Social media posts claiming a Nature Biotechnology study showed “all mRNA vaccines cause heart damage” misrepresent the findings of the study.
The study was designed to evaluate the performance of a novel method for nanoparticle detection, destined for preclinical studies. While it used LNPs in its experiments—the same technology used in COVID-19 mRNA vaccines—it didn’t show that mRNA vaccines cause heart damage. The experiments were performed in mice, not in humans. As such, the results cannot be extrapolated to humans. The study also didn’t perform experiments to assess potential pathological effects of LNPs in humans.
While myocarditis is a known side effect of COVID-19 mRNA vaccines, it’s relatively uncommon. The risk of health problems associated with COVID-19, including myocarditis, is greater than that associated with the COVID-19 mRNA vaccines. Therefore, the benefits of the COVID-19 vaccines outweigh their risk.
REFERENCES
- 1 – Luo et al. (2025) Nanocarrier imaging at single-cell resolution across entire mouse bodies with deep learning. Nature Biotechnology.
- 2 – Writing Committee. (2022) 2022 ACC Expert Consensus Decision Pathway on Cardiovascular Sequelae of COVID-19 in Adults: Myocarditis and Other Myocardial Involvement, Post-Acute Sequelae of SARS-CoV-2 Infection, and Return to Play: A Report of the American College of Cardiology Solution Set Oversight Committee. Journal of the American College of Cardiology.
