The question of what officials knew—and when—has landed back in the middle of the COVID vaccine debate. Misryoum newsroom reported that a Senate investigation points to internal awareness of a stroke risk tied to Pfizer’s bivalent COVID-19 booster, specifically in people over 65, alongside a failure to issue formal public warnings.
According to Misryoum reporting, when Joe Biden entered office, his administration leaned hard into promoting COVID vaccines. The same vaccines Biden had previously said shouldn’t be trusted became a centerpiece of his agenda, and the Senate’s new details suggest the push for that strategy came with decisions that critics describe as “shady.”
Misryoum newsroom reported that the findings include a letter sent to HHS Secretary Robert F. Kennedy Jr. by Sen. Ron Johnson (R-Wis.), backed by roughly 2,000 pages of federal documents. In that reporting, the timeline starts with the FDA authorizing the Pfizer-BioNTech COVID-19 bivalent booster on August 31, 2022. By late October 2022, HHS reported about 14.4 million people ages 12 and older had received it. Then, in November 2022, federal health officials became aware of a statistically significant safety signal for ischemic stroke among individuals age 65 and older after the booster was administered.
For clarity, an ischemic stroke happens when a blood vessel supplying the brain becomes blocked, stopping blood and oxygen from reaching parts of the brain. Misryoum newsroom reported that even as this safety signal persisted for months across multiple vaccine safety surveillance systems, Biden’s FDA and the CDC did not issue formal health alerts. They also did not advise the public to avoid the vaccine. Instead, officials continued telling the public the vaccine was safe, while internally conducting multiple studies and statistical analyses—including what is described as a “Stroke Project.” These investigations, per Misryoum reporting, continued through at least September 2025. I keep thinking about how quiet that period is in hindsight—like you only notice the change after the fact, the air in a room still the same, but something off.
Misryoum newsroom reported that between November 2022 and March 2023, seven separate analyses of incoming data flagged the same stroke signal for the same vulnerable population. That repeated signal, described as showing risk for people over 65, did not translate into any single formal warning, the Senate materials argue. In a passage cited in Misryoum reporting, Johnson wrote that HHS records show federal health officials identified a potential connection as early as October 2022 between the Pfizer-BioNTech bivalent booster and ischemic stroke for people over 65.
Misryoum reporting also says Johnson pointed to CDC data showing 226 stroke cases reported between August 2022 and February 2023, with additional cases continuing to roll in through 2024. And instead of warning the public, HHS brought in Lukos LLC in February 2023 to run an internal program called “The Stroke Project.” The program, in the Senate’s description, involved deeper dives into the data while the public message stayed focused on safety. Misryoum newsroom reported that Johnson argued officials continued to say the vaccine was safe while searching for evidence supporting that assertion—referencing contractor-led case reviews, VAERS data-mining analyses, and follow-up VSD studies referenced in MMWR publications through at least September 2024.
The Senate investigation is also framed by Misryoum newsroom reporting as part of a broader pattern. Misryoum newsroom reported that in December, FDA Commissioner Marty Makary said the Biden administration hid data from the public about links between mRNA COVID vaccines and myocarditis, including in young people. Misryoum newsroom also notes Makary’s comment that internal data showed the administration “was sitting on data” and that it wasn’t made public. Whether the same internal logic is being described across topics, Misryoum reporting suggests the core allegation is still the same: officials knew about safety signals, but treated transparency as secondary to control—at least according to the Senate’s documentation.