When Bayer acquired Monsanto for $63 billion in 2018, the German pharmaceutical giant inherited the world's most controversial crop science company—along with thousands of lawsuits over the weedkiller Roundup. What Bayer apparently didn't expect to inherit was a potential claim on billions of dollars in COVID-19 vaccine profits.

In a stunning legal maneuver filed in federal courts last week, Bayer's Monsanto subsidiary has sued the three major COVID-19 vaccine manufacturers—Pfizer-BioNTech, Moderna, and Johnson & Johnson—alleging they used patented mRNA stabilization technology originally developed for agricultural applications.

The Crop Science Connection

At the heart of the lawsuit is U.S. Patent No. 7,741,118, awarded in 2010 and not due to expire until June 2027. The patent covers technology developed by Monsanto scientists in the 1980s to strengthen messenger RNA in crops, improving mRNA stability and the quantity and quality of protein produced.

According to Bayer's complaint, the COVID vaccine makers "copied technology developed by Monsanto... in order to stabilize the genetic material used in their vaccines." The lawsuits, filed in Delaware and New Jersey federal courts, seek a jury trial, a cut of vaccine proceeds, and royalties on future sales.

"The defendants used Bayer's technology to eliminate 'problem' coding sequences in the building blocks of cells to improve mRNA stability and the amount or quality of protein produced."

— Bayer legal filing, U.S. District Court, Delaware

The $93 Billion Question

The financial stakes are staggering. According to company reports, Pfizer and BioNTech's Comirnaty vaccine generated more than $93 billion in cumulative historical sales. Moderna's Spikevax has produced similar blockbuster revenues. Even in 2024, when pandemic demand had waned significantly, Pfizer and BioNTech earned $3.3 billion from Comirnaty while Moderna generated $3.2 billion from Spikevax.

If Bayer prevails, the company could be entitled to royalties on all past and future sales—potentially representing billions of dollars in damages and ongoing payments.

The mRNA Revolution's Origin Story

The lawsuit challenges the prevailing narrative about mRNA vaccine technology. The conventional story credits decades of academic research, particularly by scientists like Katalin Karikó and Drew Weissman, whose work on modified mRNA won them the 2023 Nobel Prize in Physiology or Medicine.

Bayer's claim introduces a new wrinkle: that the practical application of mRNA stabilization—the key to making vaccines viable—drew from innovations originally intended for corn and soybeans.

"This is a classic example of technology transfer that happens in ways people don't expect," said Dr. Michael Werner, a patent attorney specializing in biotechnology at Mintz. "Agricultural biotech and pharmaceutical biotech have been converging for years, but this takes it to a whole new level."

The Companies Respond

Pfizer, BioNTech, and Moderna have all issued statements expressing confidence in their intellectual property and pledging to defend the lawsuits "vigorously."

Johnson & Johnson faces a somewhat different situation: the company stopped selling its COVID vaccine in the United States in 2023, but Bayer's lawsuit covers the period when it was still on the market.

Notably, Bayer has said it does not intend to restrict the commercial use of COVID-19 vaccines—only to collect damages for what it claims is unauthorized use of its technology.

Why Now?

The timing of Bayer's lawsuit raises questions. The vaccines have been on the market since late 2020, yet Bayer waited until 2026 to file suit. Legal experts suggest several possible explanations:

  • Patent strategy: The '118 patent expires in 2027, giving Bayer a narrow window to maximize potential damages
  • Financial pressure: Bayer continues to face massive Roundup-related liabilities and may be seeking new revenue sources
  • Settlement leverage: Filing close to patent expiration could push defendants toward settlement rather than prolonged litigation

The Broader Implications

Beyond the immediate financial stakes, the lawsuit could have significant implications for the future of mRNA technology. If courts validate Bayer's claims, it could establish precedent for agricultural patents applying to pharmaceutical applications—potentially complicating development of next-generation vaccines and therapeutics.

Both Moderna and Pfizer-BioNTech are actively developing mRNA vaccines for influenza, RSV, cancer, and other conditions. Any royalty obligations to Bayer could significantly impact the economics of these programs.

What Investors Should Watch

For pharmaceutical investors, the lawsuits add a new risk factor to vaccine-related holdings. Pfizer shares dipped 0.3% on the news, while Moderna fell 1.2%. Bayer's German-listed shares rose 2.1%.

The cases are expected to take years to resolve, but the mere existence of the litigation could weigh on valuations and complicate M&A activity in the sector.

As one pharmaceutical analyst put it: "Who would have thought that Monsanto's corn research would end up in a COVID vaccine courtroom? This industry never stops surprising you."