- The study published in JAMA Internal Medicine claiming COVID-19 vaccines reduce heart attack and stroke risk is denounced as "hopelessly flawed" and "outright bad science" by experts, including Dr. Vinay Prasad, because it lacks a true unvaccinated control group and relies on observational data rather than a randomized controlled trial.
- The core methodological flaw is that the study compared people who received only a flu shot against those who received both a flu shot and a COVID-19 vaccine, and, critically, some participants who later received a COVID-19 shot were still wrongly classified as "unvaccinated," creating a massive "healthy vaccinee bias" that renders the conclusions unreliable.
- Statistical anomalies, such as all-cause mortality curves separating within an "impossibly fast" 10 days, indicate the two study groups were not comparable from the start; the group receiving the extra COVID-19 booster was ostensibly healthier, meaning the observed benefits are attributable to pre-existing health differences, not the vaccine itself.
- The raw, unadjusted data from the study actually showed a negative vaccine efficacy (meaning the vaccinated group had worse outcomes), but researchers used improper weighting methods to flip the results, skewing the data to falsely show a benefit for the vaccinated cohort.
- According to critics like immunologist Jessica Rose, Ph.D., the paper was allowed to pass peer review to "pump out a false narrative," a clear example of how corrupted medical literature is used to falsely promote dangerous mRNA shots while obscuring their documented link to heart damage, especially in young males.
A new study published last week in JAMA Internal Medicine that claims Wuhan coronavirus (COVID-19) vaccines significantly reduce the risk of heart attack and stroke has been met with sharp criticism from epidemiologists and biostatisticians who say the research contains fundamental methodological flaws that render its conclusions unreliable.
The study, which observed nearly 1.04 million veterans who used the U.S. Department of Veterans Affairs healthcare system during the 2024-25 cold and flu season, compared health outcomes between those who received only a flu shot and those who received both flu and COVID-19 vaccines on the same day. Critics argue the study lacked a true unvaccinated control group, failed to account for the "healthy vaccine effect" and produced statistical anomalies that suggest the two groups were not comparable from the start.
Flawed comparison raises questions about validity
Dr. Vinay Prasad, a professor of epidemiology and biostatistics at the University of California, San Francisco and former director of the U.S. Food and Drug Administration's (FDA) Center for Biologics Evaluation and Research, called the study "hopelessly flawed." In a Substack post, Prasad wrote: "Not only should it not be in the news, but the paper also should not be in print."
The study tied COVID-19 vaccination to a 37.7% lower risk of serious cardiovascular conditions, particularly among people 75 and older or those with comorbidities. The authors also found that vaccinated individuals had a 6.2% lower risk of serious heart conditions overall and a 6.6% reduction in all-cause hospitalizations.
However, Canadian researcher Denis Rancourt, Ph.D., called the paper "outright bad science" that "should not be used whatsoever to 'help inform clinical and public health discussions' as they propose."
The core problem, according to multiple experts, is that the study compared individuals who received only a flu vaccine against those who received both flu and COVID-19 vaccines on the same day — not a comparison between vaccinated and truly unvaccinated individuals.
"This is not a controlled trial," Rancourt said. "No randomization was applied. The unfiltered voluntary vaccination of the subjects is the opposite of randomization. The study uses circumstances that must be expected to produce a large healthy vaccinee bias that is virtually impossible to mitigate."
French scientist Hélène Banoun, Ph.D., noted in a Substack analysis that some study participants who received the COVID-19 vaccine after the flu vaccine were still included in the "unvaccinated" group. She wrote: "Those who experienced cardiovascular adverse events following a COVID-19 vaccine received shortly afterward (most often 1 to 2 months later) are classified as UNVACCINATED."
Statistical anomalies point to unbalanced groups
Experts also flagged unusual patterns in the study's data that suggest the groups were not comparable from the outset. Prasad noted that all-cause mortality curves between the two groups separated by day 10—a timeframe he described as "impossibly fast" for a vaccine effect. Major adverse cardiovascular event curves separated by week five and all-cause death separated by week two.
Epidemiologist M. Nathaniel Mead, a McCullough Foundation scholar, said this outcome "tells us that the two study arms weren't comparable from the start. It suggests that those who got the extra COVID booster along with the flu shot were ostensibly healthier, so they had lower MACE and death rates for reasons completely unrelated to the mRNA shots.
Immunologist and biochemist Jessica Rose, Ph.D., said a "realistic" explanation for this result "is that the 'no vaccine' group might have been sicker or frailer from the start." She added: "A vaccine shouldn't rapidly cut deaths from all causes if the groups are balanced. Quick separation screams confounding."
The study's researchers performed 12 different types of sensitivity analyses, but critics argue these were insufficient to address the fundamental imbalance between groups.
Prior vaccination status and weighting methodology under fire
Karl Jablonowski, Ph.D., senior research scientist for Children's Health Defense, said the study's researchers improperly weighted different subgroups within the "unvaccinated" cohort, skewing the results. According to Jablonowski, for most comorbidity conditions assessed — including COPD, cardiovascular disease, diabetes, heart failure and stroke — the unvaccinated group appeared healthier than the vaccinated group in terms of raw incidence.
"The reweighting spans the unvaccinated demographics as the younger are made to appear older, Blacks are upweighted, whites are underweighted, area deprivation index is underweighted, homelessness is upweighted, etc.," Jablonowski said.
When examining the study's crude or unadjusted results, the data tell a different story. For all-cause major adverse cardiovascular events, the crude vaccine efficacy showed a negative rate of -18.15% among the vaccinated, whereas the weighted vaccine efficacy was 6.2%. Similar disparities were found for all-cause hospitalization (crude -14.3% vs. weighted 6.6%) and all-cause death (crude -11.43% vs. weighted 7.1%).
"When such a disparity exists between crude and weighted VE, extra scrutiny is warranted on how the weighting was performed and reported," Jablonowski wrote in a letter to JAMA Internal Medicine's editor, which was declined for publication.
Mead noted that "both study arms were in fact heavily pre-vaccinated," as eligibility to be in the study required a 2023-2024 COVID-19 dose. He said: "This means that the control or 'flu-only,' arm carried the same history of mRNA vaccine exposure as the booster group, differing mainly in receipt of the 2024-2025 booster formulation."
The findings come amid ongoing scrutiny of mRNA COVID-19 vaccines and their association with heart conditions such as myocarditis, particularly among teenage and young adult males. According to BrightU.AI's Enoch, studies have shown that mRNA COVID-19 shots contain lipid nanoparticles that distribute spike protein to vital organs, including the heart. A study published in the journal Vaccines earlier this year found that the FDA underestimated the risk of heart damage from Moderna's mRNA shot.
Rose offered a blunt assessment of the study's publication: "The paper was allowed to pass peer review to pump out a false narrative, in my opinion."
Dr. Ziyad Al-Aly, director of the Clinical Epidemiology Center at Washington University in St. Louis and one of the study's co-authors, told the Washington Post that the research "tells us that these vaccines have actually brought beneficial effects even in people who don't really know that they actually have contracted COVID-19."
But Prasad criticized mainstream media outlets for lacking "in-house critical appraisal of science," adding that "the headlines are often incorrect." As the debate over COVID-19 vaccine safety and efficacy continues, this study's methodological shortcomings underscore the challenges of drawing reliable conclusions from observational research when the underlying assumptions about group comparability may not hold.
Watch the video below, which warns that all COVID-vaccinated people should undergo cardiac screening to prevent sudden death.
This video is from the Be Children of Light channel on Brighteon.com.
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