In a new preprint study published on MedRxiv, researchers at the Florida Department of Health and the Massachusetts Institute of Technology found that people who received two doses of Pfizer’s COVID-19 vaccine were significantly more likely to die within a year than those who received Moderna’s shot.
The study, which examined more than 1.4 million adults in Florida, showed higher death rates across the board for those who received Pfizer’s mRNA vaccine—including deaths from heart-related conditions, COVID-19 itself, and all other causes.
Researchers matched 1,470,100 individuals who completed their two-dose primary series of either the Pfizer or Moderna vaccine between December 2020 and August 2021. Participants were matched based on age, sex, race, county of residence, vaccination date, and health history to ensure the comparison was as fair as possible.
One year after vaccination, those who received Pfizer’s shot had an all-cause mortality rate of 847 deaths per 100,000 people. In contrast, Moderna recipients had a significantly lower rate—just 618 deaths per 100,000. In other words, those who got Pfizer were nearly 37 percent more likely to die of any cause within a year than those who got Moderna.
Deaths from heart-related causes were also notably higher in the Pfizer group. Cardiovascular deaths occurred at a rate of nearly 249 per 100,000 for Pfizer recipients, compared to 162 for Moderna—marking a 54 percent increased risk.
Even COVID-related deaths were more frequent in the Pfizer group, despite the vaccine being designed to prevent COVID-19. Pfizer recipients died of COVID at a rate of 56 per 100,000, while Moderna recipients died at a rate of just under 30. Non-COVID deaths were also higher among Pfizer recipients.
“It has become painfully obvious that as a result of Big Pharma-driven vaccine ideology, these products do not receive the safety scrutiny they should,” Florida’s Surgeon General, Joseph A. Ladapo, said in a post on X.
“Did your doctor tell you that you might be more likely to die if you took Pfizer instead of Moderna? That’s what we found in Florida, and other studies have shown similar results. The system is rotten and we need more honest scientists,” he added.
Although the study has not yet undergone peer review, its findings raise critical questions about the safety profiles of the two most widely used COVID-19 vaccines. Researchers say the difference in outcomes may be due to subtle differences in the vaccines themselves, such as the amount of mRNA used or the way the spike protein is presented to the immune system.
Although both Pfizer and Moderna vaccines use modified RNA (mRNA) technology to instruct the body to make the spike protein found on the surface of the SARS-CoV-2 virus, Moderna’s vaccine contains more mRNA per dose than Pfizer’s.
The authors of the study also pointed to “non-specific effects” of the vaccines—meaning the shots may have unintended consequences unrelated to the virus they were designed to protect against. In this case, the Pfizer vaccine may have harmful effects on the heart and other body systems that were not seen with Moderna.
Dr. Joseph Ladapo, Florida’s Surgeon General and one of the study’s authors, has been an outspoken critic of the federal government’s handling of the pandemic and its one-size-fits-all approach to vaccination. He has repeatedly called for more transparency and independent analysis of COVID vaccine safety data, especially regarding potential heart risks in younger people.
The study’s release comes amid a growing shift in public sentiment around COVID-19 vaccines. Recent polling shows trust in the CDC and FDA has dropped, and many Americans now question whether the risks of vaccination outweigh the benefits—especially for younger, healthier individuals.
This isn’t the first time concerns have been raised about the safety of mRNA vaccines. Several studies have linked the shots, particularly Pfizer’s, to increased rates of myocarditis, a type of heart inflammation, especially in young men. However, this new research is among the first large-scale studies to compare long-term mortality outcomes between the two mRNA shots.
The findings also come as Pfizer prepares to seek regulatory approval for new mRNA-based treatments and vaccines. Critics argue the company should be held accountable for failing to thoroughly investigate or disclose the potential long-term harms associated with its COVID-19 vaccine.
Daniel O’Connor, founder and CEO of Trial Site News, said the findings raise serious safety concerns—particularly about Pfizer’s shot.
“If Pfizer’s vaccine were a drug undergoing clinical trials,” O’Connor said, “this kind of data would trigger an immediate pause—yet it continues to be administered under full regulatory protection.”
He added that he hopes the study will soon appear in a peer-reviewed medical journal so the risks can be formally acknowledged. “The public deserves transparency—not silence,” he said.
Although the study has yet to be peer-reviewed, it adds to a growing body of evidence that challenges the federal narrative that all COVID-19 vaccines are “safe and effective.” With more than 270 million doses of Pfizer’s vaccine administered in the U.S. alone, the potential implications of these findings are significant.
