The research found that people who got their flu shot were less likely to have a stroke. Specifically, the study focused on ischemic stroke, which “accounts for about 87% of all strokes,” according to the American Heart Association, and happens when blood flow to the brain is blocked.
The 14-year study took place in Spain and followed 14,322 people who had a stroke. Each person was compared to five people who had never had a stroke of the same age and sex. All study subjects were between the ages of 40 and 99.
Researchers compared the date of the stroke with the date of the flu shot to see if participants had gotten their vaccination at least 14 days before the stroke. They also looked at this time frame in people who did not have a stroke.
Approximately 41.4% of people who had a stroke during the study’s time period got their flu shot compared to 40.5% of people who had not had a stroke. However, after adjusting for issues like vascular-related conditions (people in the vaccinated group tended to have more stroke risk factors like high blood pressure or cholesterol), it was found that those who got their annual flu shot were 12% less likely to have a stroke than those who did not get the vaccine.
Experts aren’t completely sure why your flu shot could reduce your risk of stroke.
The exact reasoning behind this positive outcome is unclear right now, but researchers have some theories. Study author Dr. Francisco José de Abajo told Medical News Today that “at this stage, we can only speculate about the mechanisms, but there are several pieces of evidence from previous studies … which suggest that flu vaccination may reduce inflammation mediators.”
And according to the American Heart Association, “systemic markers of inflammation have been shown to be risk markers of stroke.” So, the reduction in inflammation could be the reason behind this decreased stroke risk in study participants.
Additionally, not all vaccines lead to a reduced stroke risk — the pneumonia vaccine did not have the same effect, researchers found, which leads them to believe there is a connection between the flu vaccine and a lower risk of stroke.
That said, the new study does have some limitations. It was observational and did not look into other factors, like diet and exercise in the study subjects’ day-to-day lives. Fitness, a nutritious diet and a healthy weight all contribute to a lower risk of stroke. It’s possible that people who are more likely to get a vaccine are also executing good health practices in other areas, too.
Either way, it’s important to get your flu shot.
The flu shot is an important way to protect yourself and those around you from contracting the virus. According to the Centers for Disease Control and Prevention, the flu kills tens of thousands of people every year and infects more than 9,000,000 people annually.
While many people can fight off the virus, it is a very risky sickness for elderly people, young children and people with diseases, like asthma and COPD, Dr. Bert E. Johansson, a vaccine expert with the National Hispanic Medical Association, previously told HuffPost.
By getting the flu shot, you’re reducing your risk of developing the virus, protecting your loved ones — and possibly even reducing your risk of stroke.
“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 in a statement. “To be able to reduce your risk of stroke by taking such a simple action is very compelling.”