The Centers for Disease Control and Prevention said Friday it was “very unlikely” that Pfizer’s Omicron booster posed a risk of stroke for seniors after they opened an investigation into a preliminary safety issue found by one of their surveillance systems would.
The CDC said in a statement posted on its website Friday that a monitoring system called Vaccine Safety Datalink has identified a possible risk of stroke in people aged 65 and older who received the Pfizer booster shot against the Omicron-Covid variant . A CDC spokesman said this problem was first discovered in late November.
In mid-December, the CDC concluded that the concern persists and launched an investigation into whether seniors are more likely to have a stroke in the first 21 days after receiving the Pfizer booster shot, the spokesman said. A similar preliminary signal was not detected for the Moderna booster.
The VSD surveillance system found that 130 people ages 65 and older had a stroke within 21 days of receiving Pfizer’s Omicron booster, among about 550,000 seniors who received the vaccine, the CDC spokesman said. No deaths were reported. The Washington Post previously reported on it.
According to the CDC, no other monitoring system has previously identified similar safety concerns for the Pfizer booster. Investigators, after reviewing data from the Center for Medicare and Medicaid Services, the Department of Veterans Affairs, the Vaccine Adverse Reporting System and Pfizer’s Global Safety Database, found no increased risk of stroke after the Pfizer booster shot.
“Although the body of data currently suggests that it is very unlikely that the signal in VSD poses any real clinical risk, we believe it is important to share this information with the public, as we have done in the past When it comes to our safety, surveillance systems detect a signal,” the CDC said in the post on its website.
According to the CDC’s Friday statement, the surveillance systems often detect safety signals stemming from factors other than the vaccine. The agency spokesman said investigators hope to have a clearer picture and more data in the coming weeks.
The investigation will be discussed at an upcoming meeting of the Food and Drug Administration’s Panel of Independent Vaccine Experts on Jan. 26.
In a statement Friday, Pfizer said there was no evidence that ischemic stroke was linked to the company’s Covid vaccine. Neither Pfizer and its German partner BioNTech, nor the CDC nor the FDA have observed such an association in numerous other surveillance systems in the United States and around the world, company spokesman Kit Longley said.
“Compared to the published incidence rates of ischemic stroke in this elderly population, the companies have seen a lower number of reported ischemic strokes after vaccination with the omicron BA.4/BA.5-adapted bivalent vaccine,” Longley said.
The CDC has not changed its recommendation for Pfizer’s Omicron shot. Everyone from the age of 5 is entitled to the booster vaccination after completing their basic series of vaccinations. The youngest children, aged 6 months to 4 years, receive the Omicron shot as the third dose of their primary series.