The Biden administration pushed COVID-19 boosters for elderly people even harder after its vaccine safety surveillance systems discovered, as early as November 2022, "statistically significant safety signals for ischemic stroke" in that age group following uptake of the Pfizer bivalent, Sen. Ron Johnson, R-Wis., told Secretary of Health and Human Services Robert F. Kennedy in a letter Monday, disclosed Wednesday.

The Permanent Subcommittee on Investigations chair released nearly 2,000 pages of "relevant HHS records" in conjunction with the letter, in 10 batches, documenting the stroke signal and internal communications between officials "acknowledging significant statistical limitations in their ability to detect safety signals through their data analyses."

The Biden White House next made edits to a draft Centers for Disease Control and Prevention and Food and Drug Administration "communications plan" to increase booster uptake, in January 2023, that "downplayed the significance of the safety signal, changing a sentence that stated that the 'signal is moderately elevated' to the 'signal is slightly elevated,'" Johnson told Kennedy.

"Biden health officials posted on FDA’s website that 'no change is recommended in COVID-19 vaccination practice,'" the same month, even as they "initiated multiple studies and statistical analyses — including a so-called 'Stroke Project” — to investigate the validity of their assertion" through at least September 2025, Johnson's office said.

He asked Kennedy for more information about detection of ischemic stroke following the booster because "the full extent of HHS’s awareness of the ischemic stroke safety signal remains incomplete and key records are still missing."

Biden officials downplayed the risk of ischemic stroke they found in coadministered COVID and flu vaccines in fall 2023.

Several months earlier they approved "additional investigation" of the booster stroke signal even while emphasizing they weren't changing vaccine recommendations, but quickly dismissed the signal after using a "different methodology."