Evidence of plasmid DNA contamination in mRNA COVID-19 vaccines finally published in the peer-reviewed literature
Implications of manufacturing-derived contamination on genetic vaccine purity and safety
A crucial article proving the presence of plasmid DNA contamination in the Pfizer/BioNTech and Moderna mRNA genetic vaccines has finally been published in the peer-reviewed scientific literature. The article, titled “Quantification of residual plasmid DNA and SV40 promoter-enhancer sequences in Pfizer/BioNTech and Moderna modRNA COVID-19 vaccines from Ontario, Canada”, authored by Dr. David J. Speicher (Substack: Courageous Truth), Dr. Jessica Rose (Substack: Jessica Rose), and Dr. Kevin McKernan (Substack: Anandamide) was published in the journal Autoimmunity [1].
The preliminary version of this work remained as a pre-print for nearly two years [2], during which time the unbiased scientific community, that adheres to evidence-based principles, eagerly awaited its formal peer-reviewed publication.
Seizing the opportunity, I invited the authors to submit the article to the Special Issue I am serving as Guest Advisor for, titled “Autoimmune Inflammatory Reactions Following Genetic Vaccination” in the aforementioned scientific journal. The article underwent a thorough peer-review process and received an impartial final decision from the Editor-in-Chief of the journal. Consequently, I am honored to have played a role in the formal publication of this critically important paper.
But why does this study hold such critical importance? While there are several compelling reasons, I would like to highlight two key points that particularly underscore its significance:
(i) The study quantitatively measured residual plasmid DNA in Pfizer-BioNTech and Moderna COVID-19 mRNA vaccine vials and found total DNA levels vastly exceeding FDA and WHO regulatory limits. In particular, using fluorometry, the total DNA content in Pfizer/BioNTech vials was found to exceed regulatory limits by 36 to 153 times, while in Moderna vials, it exceeded those limits by 112 to 627 times. Notably, the genetic vaccines released to the market were manufactured differently from those used in clinical trials. After FDA approval and rollout, Pfizer/BioNTech expanded manufacturing by shifting from initial PCR amplification, to large-scale bacterial fermentation of plasmid DNA templates, similar to Moderna’s approach, involving bacterial overexpression to produce DNA plasmids subsequently used for in vitro mRNA synthesis. This manufacturing process resulted in random contamination by double-stranded plasmid DNA, which can vary between vials. Consequently, the contents of individual vials may significantly differ from the composition declared on the drug label. This variability is especially concerning given that the levels of DNA contamination detected substantially exceed the regulatory limits established by the FDA and WHO. In simple terms, the presence of these contaminants creates a serious compliance issue with the pharmaceutical product’s composition as stated in the package insert.
It must be emphasized that this study is not an isolated case. In fact, other studies have also reported the presence of plasmid DNA contamination exceeding regulatory limits [3-5], such as the investigation conducted at the FDA White Oak facility [4]. This issue has been addressed in one of my previous articles. However, this is the first study to be published in a journal currently indexed in major databases such as PubMed, Scopus, and Web of Science.
(ii) The second crucial issue concerns the potential oncogenic risk posed by these DNA contamination. The plasmid DNA is present in high copy numbers and contains functional elements such as promoters, open reading frames, origins of replication, and nuclear targeting sequences [1-7]. Specifically, the plasmids used in the Pfizer/BioNTech’s production process are engineered with a mammalian promoter-enhancer-origin of replication from the Simian Virus 40 (SV40), along with a nuclear targeting sequence. This is especially concerning given that the SV40 virus is a well-established oncogenic virus when intact [8, 9]. In fact, Health Canada has requested data from Pfizer regarding the size distribution of DNA fragments present in its vaccines, reflecting concerns that these fragments could potentially integrate into human genomes and pose safety risks [10].
Regrettably, the defamatory apparatus aimed at discrediting any scientific voice or research questioning the established “safe and effective” narrative has already begun efforts to have this article retracted, as Dr. Kevin McKernan has informed me (see below).
I hope the excellent Editor-in-Chief of Autoimmunity will base his decisions on evidence-based science and assess the situation impartially.
In conclusion, I would like to take this opportunity to invite any researcher with a scientifically solid study (in addition to those I have already directly invited), to consider the idea of submitting their work to the aforementioned Special Issue I am guest advising. This Special Issue offers the conditions for an unbiased evaluation free from conflicts of interest, a welcomed rarity since the onset of COVID-19.
References
[1] D.J. Speicher, J. Rose, K. McKernan, Quantification of residual plasmid DNA and SV40 promoter-enhancer sequences in Pfizer/BioNTech and Moderna modRNA COVID-19 vaccines from Ontario, Canada, Autoimmunity 58 (2025) 2551517. https://doi.org/10.1080/08916934.2025.2551517.
[2] D.J. Speicher, J. Rose, L.M. Gutschi, D.M.W. PhD, K. McKernan, DNA fragments detected in monovalent and bivalent Pfizer/BioNTech and Moderna modRNA COVID-19 vaccines from Ontario, Canada: Exploratory dose response relationship with serious adverse events., (2023). https://doi.org/10.31219/osf.io/mjc97.
[3] BioNTech RNA-Based COVID-19 Injections Contain Large Amounts Of Residual DNA Including An SV40 Promoter/Enhancer Sequence - Science, Public Health Policy and the Law, (2024). https://publichealthpolicyjournal.com/biontech-rna-based-covid-19-injections-contain-large-amounts-of-residual-dna-including-an-sv40-promoter-enhancer-sequence/ (accessed December 13, 2024).
[4] T.J. Wang, A. Kim, K. Kim, A rapid detection method of replication-competent plasmid DNA from COVID-19 mRNA vaccines for quality control, Journal of High School Science 8 (2024) 427–439.
[5] K. McKernan, Y. Helbert, L.T. Kane, S. McLaughlin, Sequencing of bivalent Moderna and Pfizer mRNA vaccines reveals nanogram to microgram quantities of expression vector dsDNA per dose, (2024). https://doi.org/10.31219/osf.io/b9t7m.
[6] P. Gentilini, A Case Report of Acute Lymphoblastic Leukaemia (ALL)/Lymphoblastic Lymphoma (LBL) Following the Second Dose of Comirnaty®: An Analysis of the Potential Pathogenic Mechanism Based on of the Existing Literature - [v2], (2024). https://doi.org/10.20944/preprints202403.1661.v2.
[7] H. Banoun, mRNA: Vaccine or Gene Therapy? The Safety Regulatory Issues, International Journal of Molecular Sciences 24 (2023) 10514. https://doi.org/10.3390/ijms241310514.
[8] M. Carbone, H.I. Pass, L. Miele, M. Bocchetta, New developments about the association of SV40 with human mesothelioma, Oncogene 22 (2003) 5173–5180. https://doi.org/10.1038/sj.onc.1206552.
[9] A.F. Gazdar, J.S. Butel, M. Carbone, SV40 and human tumours: myth, association or causality?, Nat Rev Cancer 2 (2002) 957–964. https://doi.org/10.1038/nrc947.
[10] Health Canada Asked Pfizer For DNA Fragments Size In COVID Shots, Linked To 'Probability’ Of Genomic 'Integration’, Polityka (n.d.). https://polityka.co.pl/health-canada-asked-pfizer-for-dna-fragments-size-in-covid-shots-linked-to-probability-of-genomic-in-14685098.html (accessed July 8, 2025).