Can The COVID Bivalent Booster Increase The Risk Of Stroke In Older Adults?

The Pfizer/BioNTech bivalent COVID-19 vaccine could be linked to an increased occurrence of ischemic stroke in adults over 65, according to a joint statement released by The Centers for Disease Control and Prevention and the U.S. Food and Drug Administration on Friday.

The CDC's Vaccine Safety Datalink (VSD) — a database that examines adverse reactions to vaccines — found that people over the age of 65 were more likely to suffer a stroke in the three weeks after receiving the booster than they were in the following 22-44 days post-vaccination. Bloomberg reports that 130 of the 550,000 seniors who received the booster suffered a stroke within three weeks.

However, the report explains that no other safety databases were able to make this connection and they believe that the findings aren't representative of a "true clinical risk" (per FDA). While they continue to investigate the link — which will be discussed at a meeting on January 26 — no changes to vaccine recommendations have been made, and the CDC maintains that everyone over six months old should stay up to date on the bivalent booster (per CNN).

Investigators say the link has not been substantiated

Following the news break, Pfizer released a statement claiming, "Neither Pfizer and BioNTech nor the CDC or FDA have observed similar findings across numerous other monitoring systems in the U.S. and globally and there is no evidence to conclude that ischemic stroke is associated with the use of the companies' COVID-19 vaccines," (per Reuters).

The VSD flagged the link in late November, and by mid-December an investigation was launched by the CDC (per CNBC). Since then, data collected from the Center for Medicare and Medicaid Services, the Department of Veterans Affairs, the Vaccine Adverse Reporting System, and Pfizer's global database has been reviewed, and none has corroborated the VSD's findings.

This isn't the first time a COVID 19 vaccine has been linked to adverse reactions. An increased risk of myocarditis and pericarditis — conditions associated with heart inflammation – have previously been linked with the COVID-19 vaccine (per Politico). What's more, following the release of the Johnson & Johnson vaccine in April 2021, its use was temporarily paused after a link was found between the vaccine and increased incidence of thrombosis — a blood clotting condition that was most notably affecting women between the ages of 30-49.