The risk of stroke for seniors from the Pfizer Omicron booster is “very unlikely”, the US Centres for Disease Control and Prevention (CDC) has said, after it launched an investigation into a preliminary safety concern detected by one of its monitoring systems.
In a statement on its website, the CDC said a surveillance system called the Vaccine Safety Datalink (VSD) had detected, in late November, a possible risk for stroke in people aged 65 and older who received the shot targeting the Omicron variant.
CNBC reports that last month the agency launched an investigation into the risks of this category being likely to have a stroke in the first 21 days after receiving the Pfizer booster. A similar preliminary signal was not detected for Moderna’s booster.
The VSD monitoring system found that 130 people ages 65 and older had a stroke within 21 days of receiving the Pfizer Omicron booster among about 550 000 seniors who received the vaccine, a CDC spokesperson said. No deaths have been reported.
No other surveillance system has detected a similar safety concern for the Pfizer booster so far, and investigators had not seen an increased risk of stroke from the booster after reviewing data from the Centre for Medicare and Medicaid Services, the Department of Veterans Affairs, the Vaccine Adverse Reporting System and Pfizer’s global safety database.
“Although the totality of the data suggests it is very unlikely that the signal in VSD represents a true clinical risk, we believe it is important to share this information,” the CDC said.
Investigators hope to have a clearer picture and more data in the coming.
See more from MedicalBrief archives:
Omicron-specific booster shows promise in trials, under consideration for SA
Do we need another COVID-19 booster vaccine?
FDA authorises Pfizer COVID booster for children aged 5-11