Federal health officials are investigating whether there is a link between BioNTech
BNTX,
and Pfizer’s
PFE,
bivalent COVID-19 booster and stroke in seniors.
The Centers and Disease Control and Prevention and the Food and Drug Administration said Friday they plan to investigate a “preliminary…safety signal” from the CDC’s Vaccine Safety Datalink, a real-time surveillance system that monitors the safety of vaccines gathered from nine hospital systems in the U.S.
“Although the totality of the data currently suggests that it is very unlikely that the signal in VSD represents a true clinical risk, we believe it is important to share this information with the public,” the agencies said in a joint statement.
What the VSD showed was a higher instance of ischemic stroke in people who are 65 years old and older in the U.S. within the first three weeks after vaccination, compared with the rate of ischemic stroke in the three to six weeks after vaccination. Ischemic stroke, which is the most common form of stroke, happens when a vessel that supplies blood to the brain is obstructed, according to the American Stroke Association.
Less than 40% of seniors in the U.S. have received either of the updated COVID boosters that were designed to better protect against the omicron subvariants.
No safety signal has been reported for Moderna’s
MRNA,
bivalent shot.
At this time, federal health officials say there is no reason to avoid getting vaccinated or boosted while they investigate whether there is a tie between the Pfizer/BioNTech booster and stroke. The companies have not identified any concerns with ischemic stroke and their COVID vaccines in their own global safety database, nor has the Centers for Medicare and Medicaid Services or Veterans Affairs.
“Neither Pfizer and BioNTech nor the CDC or the [FDA] have observed similar findings across numerous other monitoring systems in the U.S. and globally,” a Pfizer spokesperson said in a statement. “There is no evidence to conclude that ischemic stroke is associated with the use of the companies’ COVID-19 vaccines.”
The VSD is different than the Vaccine Adverse Event Reporting System, though both systems are operated by the CDC. VAERS is a vaccine surveillance system that allows individuals to report instances of health issues or adverse events after an immunization. VAERS data has been cited online as rationale by people who have antivaccine views.
The FDA’s Vaccines and Related Biological Products Advisory Committee is expected to discuss the VSD data that triggered the investigation at a meeting on Jan. 26.