The Centers for Disease Control and Prevention (CDC) reported Friday that it found a possible safety issue with the updated or bivalent vaccines from Pfizer and BioNTech. 

In partnership with the Food and Drug Administration (FDA), the general public health agency has been monitoring the transparency and safety of the COVID-19 vaccines. In its latest update, the CDC said its real-time surveillance system Vaccine Safety Datalink (VSD) found statistical criteria that warranted an investigation into the bivalent vaccines. 

In line with the CDC, there seemed to be a security concern for ischemic stroke in people aged 65 and above who received the updated vaccines from Pfizer-BioNTech. The VSD raised the query of whether the elderly were prone to suffer an ischemic stroke 21 days after receiving the bivalent boosters.

An ischemic stroke is a condition that happens when a blood clot blocks an artery to the brain. This is taken into account essentially the most common sort of stroke since a blood clot often forms in arteries damaged by the buildup of plaques, as per the Mayo Clinic. 

Around 130 of the 550,000 seniors being monitored by the VSD system after receiving the bivalent vaccines had strokes three weeks after their vaccination, a CDC official said to CNN on condition of anonymity. Not one of the 130 patients died after the stroke. 

The CDC also maintained that it’s not possible for the detected safety signal to represent a real clinical risk since no other safety systems have reported an analogous finding. Several studies have also shown no increased risk of ischemic stroke as a result of the bivalent vaccines. 

“These strokes should not a confirmed adversarial event in the intervening time. It’s like a radar system. You’re getting a blip on the radar, and you’ve gotten to do further investigation to find whether that airplane is friend or foe,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University and a member of the CDC Advisory Committee on Immunization Practices’ Covid-19 Vaccine Work Group, told CNN. 

The CDC said no change is really useful within the COVID-19 vaccination practice. Everyone aged six months and above continues to be encouraged to get vaccinated and boosted amid the continuing coronavirus pandemic.