One of the most powerful figures at the US Food and Drug Administration (FDA) has admitted she refused the Covid-19 mRNA vaccine while pregnant—even as her agency promoted it as “safe and effective” for all pregnant women.
Dr Sara Brenner’s explosive disclosure, made on 15 May 2025 at the MAHA Institute Round Table in Washington, DC, is as revealing as it is troubling.
A preventive medicine physician, Brenner has worked at the FDA since 2019. As the FDA’s Principal Deputy Commissioner—and briefly its Acting Commissioner—Brenner was at the centre of decision-making.
Prior to that, she was Chief Medical Officer for diagnostics and was detailed to the White House to support the Biden administration’s Covid-19 response. She didn’t just participate in the pandemic response, she helped shape it from within.
“Knowing what I knew—not only about nanotechnology, about medicine, about the medical countermeasures—but also having a very strong and firm grounding in bioethics…there were many things that were not right,” she told the audience.
That someone with her seniority and access to internal data privately rejected the vaccine, while her agency promoted it to millions of pregnant women, presents a profound ethical dilemma.
Brenner’s Concerns about mRNA Safety
Brenner explained that her decision was driven by a lack of safety data, particularly around the biodistribution of the vaccine’s lipid nanoparticles (LNPs)—the tiny fat particles used to deliver the mRNA into cells.
“It was unknown at the time what the biodistribution patterns of those products were…That was my primary concern, and that exposure I was very concerned about,” said Brenner.
She had reason to be cautious.
As a nanomedicine expert who built an MD/PhD program in the field, Brenner had spent years researching the “biodistribution, excretion, metabolism and toxicities associated with engineered nanoparticles.”
“Materials that don’t exist in nature—there’s a lot of unknowns,” said Brenner.
She warned that unintended toxic effects—especially in vulnerable populations like pregnant women—could not be ignored.
“Regardless of the medical product or the intervention, there’s always going to be the need to evaluate both the intended outcomes…and the unintended consequences,” she cautioned.
Warnings Ignored
Brenner’s concerns echoed those raised in 2021 by Canadian immunologist Dr Byram Bridle, who first exposed internal documents from Japan’s regulatory agency showing that LNPs didn’t remain at the injection site, but travelled throughout the body and accumulated in organs including the ovaries, liver, spleen, and bone marrow.
At the time, Bridle’s warnings were aggressively dismissed. His reputation took a hit, and he faced institutional censure from the University of Guelph, where he was a professor, for speaking out against vaccine mandates.
Now, Brenner’s comments confirm that these concerns were not only valid—they were quietly shared at the highest levels of the FDA.
During the event, Brenner also revealed that her worries extended to breastfeeding and potential exposure to her child after birth.
A 2022 study published in JAMA Pediatrics detected vaccine-derived mRNA in the breast milk of vaccinated mothers for at least 48 hours—the very scenario Brenner had feared.
Yet the FDA made little effort to publicly investigate or address the findings, dismissing them with the vague reassurance that there was “no evidence of harm.”
No Mandate for Brenner?
It’s unclear how Brenner managed to avoid the vaccine mandate that applied to all federal employees at the time. She didn’t say. Perhaps she received a religious or medical exemption—but she left that part out.
What she did reveal was that she had concerns—deep enough not to take the vaccine during her pregnancy. Yet she said nothing publicly, while her agency told millions of other women it was safe.
For many, that silence is hard to accept, and it has left many asking why she didn’t warn other women about a product with ‘zero’ clinical safety data in pregnancy.
No one but Brenner knows the full story. But the ethical contradiction is hard to ignore.
Silence Inside the Castle
Brenner acknowledged the immense pressure inside the FDA to stick to the official narrative.
“They don’t let you get very far out of the castle at FDA with your talking points,” she admitted nervously.
She described the period as a “dark night of the soul” for many civil servants, a time when even “very obvious things” took bravery to say.
She eventually found support through a group called Feds for Medical Freedom—federal workers advocating for informed consent, bodily autonomy, and pushing back against government overreach.
A Culture Change?
Today, under a new administration, Brenner says the culture inside the FDA is shifting. She praised Commissioner Dr Marty Makary and said transparency is finally becoming a priority.
“We’re moving very quickly to make it such that there will be more transparency…so that people can see and evaluate for themselves what the truths are.”
But Brenner’s remarks won’t undo what has already happened—especially to those who were vaccine-injured or whose pregnancies were affected.
What her comments do offer is a rare glimpse into the internal dynamics of a government institution that issued sweeping public assurances while failing to acknowledge its own uncertainty.
“There was no acknowledgement of what was unknown. There were only statements and assertions that were really more like beliefs,” Brenner said of the FDA’s messaging during the pandemic.
That may be her most important admission.
This is more than a story about one woman’s personal decision. It is a story about institutional culture, regulatory failure, and the consequences of silence.
Those who spoke up were punished. Those who stayed silent kept their jobs and reputations. And those who were forced to comply were often left to deal with the collateral damage.
When asked whether she believed she had made the right decision in refusing the Covid-19 vaccine, Brenner replied simply, “I believe so.”
Now that she has spoken, the question remains—who else knew, and said nothing?
Maryanne Demasi, 2023 Brownstone Fellow, is an investigative medical reporter with a PhD in rheumatology, who writes for online media and top tiered medical journals. For over a decade, she produced TV documentaries for the Australian Broadcasting Corporation (ABC) and has worked as a speechwriter and political advisor for the South Australian Science Minister.
