Federal health officials were aware of serious safety concerns linked to Pfizer’s COVID-19 booster shot — including strokes and heart inflammation — but chose to conceal or minimize those risks from the American public, according to new evidence detailed in a Senate investigation.
The findings were laid out in a letter from Sen. Ron Johnson (R-WI) to HHS Secretary Robert F. Kennedy, Jr., and drew on internal agency records, emails, and data from multiple federal vaccine surveillance systems.
Strokes Hidden in Plain Sight
The trouble began almost immediately after the FDA authorized Pfizer’s bivalent COVID booster in late August 2022.
By late November of that year, the CDC’s Vaccine Safety Datalink (VSD) — a surveillance network designed specifically to catch these kinds of problems — flagged a statistically significant safety signal: older adults aged 65 and above appeared to be suffering ischemic strokes at elevated rates following the booster. An ischemic stroke occurs when a blood clot blocks an artery to the brain, cutting off oxygen — and it can be fatal or permanently disabling.
The signal didn’t fade. It persisted for months across multiple surveillance systems. And internally, officials knew it was serious. One senior CDC official tracked 226 stroke cases in VAERS data spanning just six months. Among the reported deaths were a 13-year-old girl and a 61-year-old man. An otherwise healthy 8-year-old boy suffered four transient ischemic attacks — mini-strokes — after receiving the booster.
Yet publicly, officials said nothing. At least not right away.
Behind the scenes, they quietly launched a flurry of internal investigations, including a project internally referred to as the “Stroke Project.” But they did not issue health alerts or recommend any precautions for vulnerable populations.
On January 11, 2023, CDC Director Rochelle Walensky received a draft communications plan that had been edited by the Biden White House. One line originally described the stroke signal as “moderately elevated.” Someone at the White House — it remains unclear who — changed that to “slightly elevated.” The two words carry very different meanings for patients and physicians trying to weigh risk.
Two days later, the FDA and CDC quietly posted a notice on the FDA’s website acknowledging the stroke signal. But it came with an unusual emphasis: in bolded text, twice, the agencies stated that “no change is recommended in COVID-19 vaccination practice.”
Meanwhile, Pfizer submitted a confidential response to the FDA asserting there was “no evidence” of a stroke safety signal, a claim the ongoing internal federal investigations appeared to contradict.
As recently as September 2025, a CDC presentation under the Trump administration acknowledged the stroke signal was still under analysis, years after officials had been publicly calling the vaccine safe.
A Pattern: The Myocarditis Cover
The stroke story wasn’t an isolated incident. A report published by the Senate’s Permanent Subcommittee on Investigations in August 2025 found a nearly identical pattern with myocarditis — heart inflammation — beginning far earlier in the vaccine rollout.
By February 2021, just weeks after the initial vaccine rollout, CDC officials were already receiving reports of myocarditis, pericarditis, and related cardiac events in young people. That month alone, 64 such cases had been logged in VAERS, including two deaths.
At a February 26 interagency meeting, officials from the CDC, FDA, and NIH reviewed a far starker picture: nearly 20,000 adverse events had already been reported across both the Pfizer and Moderna vaccines, including 980 deaths, many of them cardiac.
Israel, which had rapidly vaccinated its population and was effectively serving as a real-world testing ground for the Pfizer shot, was already flagging the problem. Its Ministry of Health had reported roughly 40 myocarditis cases among people aged 16 to 30 and notified U.S. health agencies directly.
By May 2021, VAERS had logged 487 cardiac cases. That same month, a CDC vaccine safety committee confirmed the myocarditis signal was real, particularly in males aged 16 to 24. Committee notes show the question was put plainly: “Is VAERS signaling for myopericarditis now?” The answer: “For the age groups 16-17 years and 18-24 years, yes.”
The committee recommended sending a Health Alert Network (HAN) message — a formal, urgent notice to doctors and public health officials across the country.
Three officials pushed back and blocked it: White House Deputy Communications Director Benjamin Wakana, Acting FDA Commissioner Janet Woodcock, and FDA biologics chief Peter Marks.
No alert went out. Instead, the CDC posted a low-key note on its website mentioning “increased cases” of the conditions, immediately followed by a strong recommendation that all Americans 12 and older get vaccinated.
Throughout this period, officials continued to describe myocarditis cases as “rare,” even while acknowledging internally that VAERS data — by the agency’s own long-standing estimates — undercounts actual adverse events by a factor of roughly 20.
A recent study of over one million children found that myocarditis occurred only in vaccinated kids.
Criminal malfeasance at the highest levels.
What's new? Par for the progressive course.