Healthy Man Dies of Toxic Shock After Taking Moderna’s New Bird Flu mRNA Vaccine

He entered the trial as a healthy volunteer. His death got buried in the fine print.

This article originally appeared on Jon Fleetwood’s Substack and was republished with permission.

Guest post by Jon Fleetwood

Moderna scientists previously admitted mRNA drugs exhibit “unacceptable toxicity” levels, with Moderna LNPs accumulating in mammalian liver, spleen, plasma (blood), kidney, heart, and lung.

A healthy 74-year-old man died from toxic shock syndrome during Moderna’s Phase 1/2 clinical trial of its experimental mRNA-1018 pandemic influenza vaccine, according to a study published in April in Clinical Infectious Diseases by scientists from Moderna and collaborating institutions.

The Moderna and collaborating scientists claim the death was unrelated to the Moderna shot, but without explaining how that determination was made.

The findings come as Moderna advances its mRNA-1018 pandemic bird flu vaccine with up to $54.3 million in support from the Bill Gates-backed Coalition for Epidemic Preparedness Innovations (CEPI), after the U.S. Department of Health and Human Services terminated its previous funding for the program.

A January 2023 Nature Reviews Drug Discovery paper co-authored by Moderna scientists bluntly admits that avoiding “unacceptable toxicity” in mRNA vaccines remains a major challenge, warning that “lipid nanoparticle structural components, production methods, route of administration and proteins produced from complexed mRNAs all present toxicity concerns” and that the way these vaccines spread through the body can cause harm due to “cell tropism and tissue distribution… and their possible reactogenicity.”

Moderna submitted data in November 2017 proving their mRNA vaccine lipid nanoparticles (LNPs) accumulate in mammalian liver, spleen, plasma (blood), kidneys, heart, and lungs.

Toxic shock syndrome is typically attributed to toxins produced by certain bacterial infections, but the paper provides too little clinical information to independently assess whether another mechanism, like LNPs or vaccine-induced immune system damage, may have contributed to the participant’s death.

The trial evaluated five experimental mRNA vaccine candidates collectively known as mRNA-1018, which were intended to protect against influenza A viruses considered to have pandemic potential, including H5N1, H5N8, and H7N9.

The study enrolled only healthy adults at sites across the United States and United Kingdom, with participants receiving two injections administered 21 days apart.

“Eligible participants were healthy adults ≥ 18 years,” the paper confirms.

In fact, according to the supplementary data, participants were required to be healthy based on their medical history, physical examination, laboratory testing, and electrocardiogram results, while individuals with unstable medical conditions, immunodeficiency, immune-mediated disease, or significant laboratory abnormalities were excluded from enrollment.

The vaccines are said to consist of messenger RNA packaged inside lipid nanoparticles that encode influenza surface proteins.

The drugs were manufactured using the same mRNA platform Moderna uses for its licensed products, like its COVID-19 shot.

The study reports the death:

“One death (due to toxic shock syndrome), assessed as not related to the study vaccine, was reported on day 139 for a 74-year-old male who had received two 50 µg doses of H7-only,” the authors wrote.

The publication offers no further narrative describing the fatal case.

It does not identify the bacterial organism responsible for the toxic shock syndrome, disclose whether the participant had developed a preceding infection, report hospitalization details, discuss laboratory findings, provide autopsy information, or explain the methodology investigators used to conclude that the death was unrelated to vaccination.

The absence of those details leaves readers unable to independently evaluate the fatal event or the investigators’ causality assessment.

Because the participant entered the trial as a healthy adult, the paper raises questions it does not answer about whether the fatal illness was entirely unrelated to vaccination or whether the vaccine may have contributed through an unidentified biological mechanism.

The publication does not investigate whether vaccine components themselves, expression of the encoded influenza proteins, immune system damage, or another pathway played any role in the participant’s inability to survive the illness.

Instead, it simply reports the investigators’ conclusion that the death was unrelated to the study vaccine.

Beyond the fatality, investigators reported additional serious adverse events during the study.

The paper states that 24 participants in Part A and four participants in Part B experienced serious adverse events.

One serious adverse event, syncope (fainting), was considered related to vaccination.

Investigators also identified two vaccine-related cases of thrombocytopenia (abnormally low number of platelets called thrombocytes in the blood) and one vaccine-related case of acute thyroiditis (inflammation of the thyroid gland) that resulted in a participant discontinuing the study.

Most participants also experienced short-term reactions following vaccination.

Across the various vaccine candidates and dose levels, solicited local reactions—including injection-site pain—occurred in approximately 70% to more than 90% of participants, while systemic reactions such as fatigue and headache occurred in more than half.

Higher doses generally produced higher rates of adverse reactions.

Bottom Line

Moderna’s own study reports that a healthy participant died from toxic shock syndrome after receiving its experimental pandemic bird flu mRNA-1018 vaccine, yet the fatality is summarized in a single sentence before investigators declare it unrelated to vaccination.

That omission matters even more because Moderna scientists have separately acknowledged that mRNA vaccines face potential “unacceptable toxicity” concerns involving lipid nanoparticles and the proteins produced by the injected mRNA, while Moderna’s own data showed its LNPs can accumulate in mammalian organs.

Without the clinical evidence behind the death investigation, readers are left unable to evaluate whether the fatal event was truly unrelated—or whether the vaccine contributed through a mechanism the paper never examines.

Copyright 2026 Jon Fleetwood

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