USA – FDA and CDC investigate potential safety concern for Pfizer/BioNTech’s COVID-19 vaccine

The US Food and Drug Administration (FDA) and US Centers for Disease Control and Prevention (CDC) are investigating whether Pfizer/BioNTech’s updated COVID-19 vaccine could be linked with an increased risk of ischaemic stroke in older adults.

The investigation was prompted by preliminary data from the CDC’s vaccine safety monitoring system, which raised a question of whether people aged 65 years and older who received the bivalent vaccine were more likely to have an ischaemic stroke in the 21 days following vaccination, compared with days 22-42.

An ischaemic stroke, also known as brain ischaemia, occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from receiving oxygen and nutrients…