New study reveals widespread DNA contamination in Pfizer and Moderna vaccines
By willowt // 2025-09-23
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  • Researchers detected high levels of DNA impurities, including SV40 promoter sequences, in Pfizer and Moderna COVID-19 mRNA vaccines, exceeding safety limits.
  • Plasmid DNA from E. coli used in manufacturing was not fully removed.
  • Contaminants may cause unintended immune reactions, including septic shock or integrating into human cells.
  • Health Canada and other agencies have ignored these findings, dismissing potential risks.
  • Independent replication of studies and clearer regulatory guidelines are urgently needed.
On September 22, a groundbreaking study by researchers including Kevin McKernan, Jessica Rose and colleagues revealed significant contamination in Pfizer and Moderna mRNA COVID-19 vaccines. The study, published in the journal Autoimmunity, presented evidence of widespread DNA impurities, including the Simian Virus 40 (SV40) promoter, in the vaccine vials. The discovery has ignited a heated debate about potential risks, regulatory oversights and the need for clearer guidelines to ensure vaccine safety. Five key points to understand the news
  1. Researchers found high levels of DNA in Pfizer and Moderna vaccines, far exceeding regulatory safety thresholds.
  2. Contaminants like the SV40 promoter, known to cause cancer in lab animals, were identified in Pfizer vaccines but not in Moderna’s.
  3. Plasmid DNA from E. coli used in manufacturing did not fully eliminate residual DNA, posing potential risks.
  4. Health authorities like the CDC claim no DNA integration issues, despite mounting evidence to the contrary.
  5. The findings raise urgent calls for independent replication and clearer regulatory oversight to ensure vaccine safety.
During the height of the pandemic, mRNA vaccines were heralded as the miracle solution to end the global health crisis. Yet, even as these vaccines were rushed through regulatory approval, questions about their long-term safety and manufacturing processes remained largely unanswered. Now, with new evidence surfacing, experts are calling for urgent action to address the risks uncovered.

SV40 and other contaminants: What's in the vaccines?

The study, which examined 32 vials from 16 unique lots of Pfizer and Moderna vaccines, used two methods to quantify DNA contamination: quantitative PCR (qPCR) and fluorometry. The findings were alarming: not only was there DNA in the vials, but levels significantly exceeded regulatory limits set by the FDA and WHO—some by as much as 627 times. Moreover, the SV40 promoter, a potent gene enhancer associated with cancer in laboratory animals, was found in all Pfizer vials tested. This sequence likely originated from the E. coli plasmid DNA used to generate the spike protein mRNA during manufacturing. While regulators like Health Canada and the CDC continue to claim "no DNA integration," these findings directly challenge those assertions. Contamination concerns:
  1. Bacterial plasmid DNA: Remnants from E. coli used in production may harbor endotoxins, such as lipopolysaccharide (LPS), known to cause severe immune reactions.
  2. Double-stranded RNA (dsRNA): dsRNA is recognized by the immune system as a viral marker, potentially triggering inflammatory responses.
  3. Antibiotic resistance genes: The study identified sequences that code for antibiotic resistance, further complicating the safety profile.

Potential health risks and regulatory criticisms

These contaminants pose significant risks to human health. Bacterial DNA like LPS can induce immune responses and, in sufficient quantities, trigger septic shock. SV40 promoter sequences, capable of enhancing gene expression, could potentially integrate into human DNA, raising the specter of increased cancer risk. Vaccinologist Dr. Byram Bridle of the University of Guelph emphasized the urgency of Health Canada investigating these findings. "The SV40 promoter is a bioactive genetic sequence capable of causing harm," he stated. "We need a thorough investigation to ensure the safety of these vaccines, especially for vulnerable populations like pregnant women." Critics argue that regulatory bodies like the FDA and Health Canada have consistently downplayed these findings, prioritizing speed over scrutiny. McKernan pointed out, "They’re getting directly funded by the companies they regulate, creating a conflict of interest." This apparent bias has raised concerns about the transparency and independence of the regulatory process.

Independent replication and clearer guidelines needed

The study authors call for independent replication of their findings under stricter forensic conditions. They also urge regulatory agencies to revise guidelines to account for the high efficiency of lipid nanoparticle (LNP) transfection and cumulative dosing. Kevin McKernan emphasized, "These data extend existing concerns about vaccine safety and call into question the relevance of guidelines conceived before the introduction of LNPs. We need clear, consistent guidelines and transparent evidence that products are safe and effective."

Urgent calls for transparency and consensus

The revelations from this study underscore the pressing need for greater transparency, independent investigation and clearer regulatory oversight in vaccine manufacturing. As health authorities like the CDC continue to downplay potential risks, the work of McKernan and his team remains a critical step toward ensuring public trust and safety. The findings also highlight the importance of adhering to the precautionary principle, advocating for sufficient and transparent evidence in vaccine development and distribution. As Senator Ron Johnson’s submission to the Congressional Record underscores, urgent action is required to address these issues. "The presence of SV40 promoter sequences and other contaminants in Pfizer vaccines raises significant safety concerns," he concluded. "We must ensure that the vaccines we administer are not only effective but also safe for all populations." This story only underscores the complexity of vaccine development and the delicate balance between speed and safety. As new evidence continues to surface, it is clear that transparency and careful scrutiny will be essential to addressing these concerns and fostering public confidence in future vaccine efforts. Sources for this article include: BrowstoneInstitute.org TandFonline.com hsgac.senate.gov
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