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Pfizer, BioNTech and Moderna Must Face Bayer Patent Lawsuits Over COVID-19 Vaccines

by Virginia M. Tjan, MD | Sep 29, 2026
Gloved hands draw liquid from a vaccine vial into a syringe against a blue background of virus-like particles.
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Pfizer, BioNTech and Moderna must continue defending patent lawsuits accusing them of using technology developed by Monsanto decades ago to manufacture their COVID-19 vaccines after a federal judge in Delaware rejected the companies’ efforts to dismiss the cases.

U.S. Circuit Judge William Bryson, sitting by designation in the U.S. District Court for the District of Delaware, ruled Monday that the vaccine makers had not shown at this early stage that Monsanto’s patent was invalid or that their vaccines did not infringe it. The decision keeps Bayer’s lawsuits alive, but it does not establish that Pfizer, BioNTech or Moderna violated Monsanto’s patent rights.

Bayer’s Monsanto unit sued Moderna and Pfizer and BioNTech separately in January over U.S. Patent No. 7,741,118. The company says Monsanto scientists began developing the technology in the 1980s while studying ways to strengthen genetic material in crops, long before messenger RNA vaccines became part of modern medicine.

Pfizer and BioNTech’s Comirnaty and Moderna’s Spikevax use messenger RNA, or mRNA, to give cells genetic instructions for producing a version of the coronavirus spike protein. The immune system recognizes that protein and learns to respond to it, preparing the body to fight the virus if it is later exposed.

For that process to work, the genetic instructions must remain stable enough for cells to read them and produce the intended protein. Bayer alleges that the vaccine makers used methods covered by Monsanto’s patent to stabilize genetic material during vaccine manufacturing.

The ruling itself does not address the safety or effectiveness of the vaccines. Bayer is seeking monetary damages for the alleged use of its patented technology rather than an order stopping Pfizer, BioNTech or Moderna from making or selling their vaccines.

Bryson’s decision also comes at an early point in the litigation. A motion to dismiss tests whether a plaintiff has alleged enough to pursue a legally viable claim; it does not decide whether the allegations are ultimately true. Bayer will still have to prove that the patent covers the technology at issue and that the vaccine makers’ manufacturing processes infringe it.

Pfizer and BioNTech argued that their manufacturing methods operate differently from the process covered by Monsanto’s patent. Moderna raised a separate challenge, arguing that portions of the patent cover an unpatentable “law of nature” rather than a human invention.

U.S. patent law does not allow a company to patent a naturally occurring phenomenon by itself. An invention that applies a natural principle through a qualifying process or technology, however, may be eligible for patent protection. Bryson declined to end Bayer’s case on Moderna’s argument at this stage, leaving that dispute to be developed as the litigation continues.

Bayer said after the ruling that it was pleased with the decision and remained confident that its patented innovations had been used without authorization. Representatives for Pfizer, BioNTech and Moderna did not immediately comment on the ruling.

The unusual history behind the patent adds another layer to the dispute. Monsanto developed the technology years before mRNA vaccines became central to the global response to COVID-19. Bayer acquired Monsanto in 2018 and, with it, the agricultural company’s extensive patent portfolio.

The cases also join a much broader fight over who owns the technology behind COVID-19 vaccines. Moderna has separately accused Pfizer and BioNTech of infringing patents involving mRNA technology used in Comirnaty, part of years of litigation over the scientific advances that helped make the vaccines possible.

Bayer has also sued Johnson & Johnson in federal court in New Jersey over the same Monsanto patent. That case, which involves technology allegedly used in manufacturing Johnson & Johnson’s COVID-19 vaccine, remains pending.

With the dismissal motions resolved, the Delaware cases can move closer to the science at the center of the dispute: what Monsanto’s patent actually covers, how Pfizer, BioNTech and Moderna manufacture their vaccines, and whether those processes overlap in a way that amounts to patent infringement.

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Virginia M. Tjan, MD
Dr. Virginia Tjan, MD, is a physician and Law Commentary journalist who brings a medical perspective to reporting on healthcare, patient care, and issues at the intersection of medicine and the law. Her clinical work focuses on the diagnosis and treatment of complex cancers, with particular experience in breast cancer, lung cancer, colorectal cancer, and multiple myeloma. She has worked with patients throughout the course of cancer care, from initial diagnosis through treatment of advanced disease, including chemotherapy, infusion therapy, diagnostic monitoring, and the management of treatment-related complications. Through her contributions to Law Commentary, Dr. Tjan helps readers better understand medical developments and healthcare issues that carry legal, regulatory, and public policy implications.

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