U.S. FDA and CDC see early signs of possible Pfizer bivalent COVID shot link to stroke
This story was refiled on January 13 with an edited headline to clarify that the link to a stroke is possible, but not certain.
According to preliminary data analyzed by US health authorities, a safety monitoring system flagged that Pfizer Inc (PFE.N) and German partner BioNTech’s updated COVID-19 shot could be linked to a type of brain stroke in older adults.
The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) announced on Friday that a CDC vaccine database found that people 65 and older were more likely to have an ischemic stroke 21 days after receiving the Pfizer/BioNTech bivalent shot, compared to days 22-44.
Blockages in the arteries that carry blood to the brain cause an ischemic stroke, also known as brain ischemia.
The FDA and CDC stated that other large studies, the CDC’s Vaccine Adverse Event Reporting System, databases from other countries, and Pfizer-BioNTech databases had not flagged this safety issue and that further investigation is required.
“Although the sum of the data currently suggests that the signal in VSD (Vaccine Safety Datalink) represents a true clinical risk, we believe it is important to share this information with the public,” health officials said.
In a statement, Pfizer and BioNTech stated that they have been made aware of a small number of reports of ischemic strokes in people 65 and older following vaccination with their updated shot.
“Neither Pfizer nor BioNTech, nor the CDC or FDA, have observed similar findings across numerous other monitoring systems in the United States and globally, and there is no evidence to conclude that the companies’ COVID-19 vaccines are associated with ischemic stroke,” the companies added.
This safety concern has not been identified with Moderna’s (MRNA.O) bivalent shot, and the CDC and FDA continue to recommend that everyone aged 6 months and older have their COVID-19 vaccination up to date.