Was this supposed to support the Nicolas Hulscher tweet, because if it was, it failed. I'm guessing based on the anti-vaxxers who liked the post, they also thought it supported that fake whack-a doodle's findings. lol
It was too long so I asked Claude to summarize it.
Here's a summary of the paper (Karimi et al.,
International Journal of Preventive Medicine, 2025 — "COVID-19 Vaccination and Cardiovascular Events: A Systematic Review and Bayesian Multivariate Meta-Analysis of Preventive Benefits and Risks"):
What it did
The researchers systematically reviewed fifteen studies on COVID-19 vaccination and cardiovascular events, with eleven of them comparing vaccinated versus unvaccinated groups, and six studies used to specifically compare the mRNA vaccines (Pfizer-BioNTech and Moderna). Rather than analyzing each cardiovascular outcome separately, they used a
Bayesian multivariate meta-analysis — jointly modeling myocardial infarction, stroke, arrhythmia, and coronary artery disease (CAD) together to account for correlations between these outcomes, with Markov chain Monte Carlo methods and sensitivity testing across different statistical priors.
OvidOvid
Key findings
- The analysis found a link between vaccination and increased CAD risk (odds ratio 1.70, 95% credible interval 1.11–2.57), which was particularly associated with the Pfizer-BioNTech (BNT162b2) vaccine (odds ratio 1.64). ScienceOpen
- This elevated CAD signal was specifically tied to the second dose. Wordpress
- Importantly, the odds of myocardial infarction, stroke, and arrhythmia did not show a significant increase overall. Wordpress
- The study also found protective effects against stroke and myocardial infarction after the third (booster) dose. Scribd
Conclusion
The paper's overall takeaway is fairly balanced rather than alarmist:
vaccination was not associated with increased risk across most cardiovascular outcomes, and boosters even appeared protective for some of them — CAD after the second dose was the one signal that stood out. The authors frame this as reason for continued vigilance and further study of cardiovascular safety in future vaccine development, rather than a reason to abandon vaccination — they emphasize the need for further examination of vaccine-related cardiovascular risks in future vaccine development efforts.
Scribd
One note: this specific finding (the CAD/second-dose signal) has been circulating in anti-vaccine spaces as if it were the study's main conclusion, when the paper's broader message is more mixed — n
o significant risk increase for most outcomes, and some protective effects from boosters.