Pfizer’s COVID-19 vaccine has been linked to blood clotting in older individuals, according to the U.S. Food and Drug Administration (FDA).
FDA researchers, crunching data from a database of elderly persons in the United States, found that pulmonary embolism—blood clotting in the lungs—met the initial threshold for a statistical signal and continued meeting the criteria after a more in-depth evaluation.
Three other outcomes of interest—a lack of oxygen to the heart, a blood platelet disorder called immune thrombocytopenia, and another type of clotting called intravascular coagulation—initially raised red flags, researchers said. More in-depth evaluations, such as comparisons with populations who received influenza vaccines, showed those three as no longer meeting the statistical threshold for a signal.
Researchers looked at data covering 17.4 million elderly Americans who received a total of 34.6 million vaccine doses between Dec. 10, 2020, and Jan. 16, 2022.
The study was published by the journal Vaccine on Dec. 1.
The FDA said it was not taking any action on the results because they do not prove the vaccines cause any of the four outcomes, and because the findings “are still under investigation and require more robust study.”
Dr. Peter McCullough, chief medical adviser for the Truth for Health Foundation, told The Epoch Times via email that the new paper “corroborates the concerns of doctors that the large uptick in blood clots, progression of atherosclerotic heart disease, and blood disorders is independently associated with COVID-19 vaccination.”
Pfizer did not respond to a request for comment.
How the Research Was Done
FDA researchers, with assistance from researchers with the Centers for Medicare & Medicaid Services (CMS), analyzed data from the CMS database. They included Medicare Fee-for-Service beneficiaries aged 65 or older who received a vaccine within the timeframe, were enrolled when they were vaccinated, and were enrolled for a “clean window” of time prior to vaccination. The window was 183 days or 365 days, depending on the outcome.
About 25 million people receive the Medicare Fee-for-Service, but only about 17 million were vaccinated during the period of time studied.