According to studies, getting an annual flu vaccination shot may help lessen the risk of stroke.
The study’s findings were published in the American Academy of Neurology’s medical publication.
“Studies have shown that getting the flu increases your risk of having a stroke, but research is still being collected on whether getting the flu vaccine shot can help protect against a stroke,” said study author Francisco J. de Abajo, MD, MPH, PhD, of the University of Alcala in Madrid, Spain.
“This observational study suggests that those who have a flu shot have a lower risk of stroke. To determine whether this is due to a protective effect of the vaccine itself or to other factors, more research is needed.”
The study focused on ischemic stroke, the most frequent kind of stroke caused by a stoppage of blood supply to the brain.
The study used a health care database in Spain to identify participants who were at least 40 years old and had their first stroke over a 14-year period. Each stroke patient was compared to five other persons of the same age and gender. There were 14,322 strokes and 71,610 persons who did not suffer a stroke.
The researchers next looked at whether patients had gotten the influenza vaccination at least 14 days before to the stroke, or before that period in the case of those who did not have a stroke.
Then the researchers looked at whether people had received the influenza vaccine at least 14 days before the stroke or before that same date for those who did not have a stroke.
A total of 41.4% of those who had a stroke had received the flu shot, compared to 40.5% of those who did not have a stroke. But the people who got the shot were more likely to be older and to have other conditions such as high blood pressure and high cholesterol that would make them more likely to have a stroke. Once researchers adjusted for those factors, they found that those who received a flu shot were 12% less likely to have a stroke than those who did not.
The researchers also looked at whether the pneumonia vaccine had any effect on the risk of stroke and found no protective effect.
“These results are yet another reason for people to get their yearly flu shot, especially if they are at an increased risk of stroke,” de Abajo said. “To be able to reduce your risk of stroke by taking such a simple action is very compelling.”
Because the study was observational, it cannot establish that getting vaccinated against the flu decreases the risk of stroke. It just demonstrates a relationship. Other variables that were not examined might have an impact on stroke risk.