• Neurosciences

    Mayo Clinic Minute: Flu vaccine may reduce risk of stroke

Getting a flu shot may offer an added benefit. A recent study published in Stroke, an American Heart Association journal, suggests flu vaccination might lower the chances of stroke among adults, especially people under 45.

Dr. Gyanendra Kumar, a Mayo Clinic neurologist not involved in the study, says it's long been known that respiratory infections increase the risk of stroke in the days following infection.

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Flu symptoms can come on suddenly, including cough, sore throat, fatigue and sometimes a fever.

"Respiratory infections, in the first three days after the onset of the infection, increase the risk of a stroke," says Dr. Kumar.

There are several theories on why getting the flu might increase the chances of stroke.

"Some of these are increased hypercoagulable state, a transient period where you have a greater predisposition to form clots," says Dr. Kumar.

When clots form, they can block blood flow to the brain.

illustration of a stroke

There are two broad subtypes of strokes: the ischemic kind, which is the clotting kind of stroke, and the hemorrhagic, or the bleeding type of stroke. The vast majority of strokes, close to 90%, are ischemic strokes," he explains.

A stroke is a medical emergency. That's why reducing risks are so essential, and the flu shot may be another tool.

"This has the potential to prevent clotting disorder and manage stroke, potentially," says Dr. Kumar.

For the safety of its patients, staff and visitors, Mayo Clinic has strict masking policies in place. Anyone shown without a mask was recorded prior to COVID-19 or recorded in an area not designated for patient care, where social distancing and other safety protocols were followed.