The Johnson & Johnson and AstraZeneca COVID vaccines are under the microscope for their potential to cause blood clots, but scientists warn Pfizer and Moderna vaccines pose similar risks.
U.S. and European health officials are scrutinizing the Johnson & Johnson (J&J) and AstraZeneca COVID vaccines for possibly causing blood clots and related blood disorders in vaccine recipients.
But evidence is mounting that the Pfizer and Moderna vaccines cause similar adverse reactions — and U.S. regulatory officials were alerted to that fact as far back as December 2020.
The Centers for Disease Control and Prevention (CDC) on Wednesday convened an emergency meeting of its Advisory Committee on Immunization Practices (ACIP) to determine whether to lift a ban on the J&J vaccine. The ban was put in place Tuesday, after reports of blood clots.
During the meeting, committee members hailed the Pfizer and Moderna mRNA vaccines as great alternatives to the J&J vaccine because there were “no safety signals” — suggesting, unlike the J&J and AstraZeneca adenovirus-based vaccines, mRNA vaccines are not associated with blood clots.
On Tuesday, Peter Marks, director of the Center for Biologics Evaluation and Research at the U.S. Food and Drug Administration (FDA), said on a call with reporters there had been no reported cases of cerebral venous sinus thrombosis (CVST) with thrombocytopenia (low blood platelets that can cause dangerous internal bleeding) following Pfizer and Moderna vaccines.
But Mark’s statement contradicts numerous news reports, recent studies and even a scientist’s warning directed specifically to Marks late last year — it also contradicts data from the Vaccine Adverse Event Reporting System (VAERS).
Utilizing a search criteria that included reports of blood clots associated with blood coagulation disorders, VAERS yielded a total of 795 reports for all three vaccines from Dec. 14, 2020 through April 1, 2021.
Of the 795 cases reported, there were 400 reports attributed to Pfizer, 337 reports with Moderna and 56 reports with J&J — far more than the eight cases under investigation, including the two additional cases added Wednesday.
