It’s well known that getting a flu shot can help protect you from the influenza virus each year, but new research suggests the vaccine may have another unexpected benefit. A study out of the University of Texas Health Science Center at Houston (UT Health) finds people 65 and older who get an annual flu vaccine may have better brain health and a lower risk of Alzheimer’s disease.
The new research is set to be published August 2 in the Journal of Alzheimer’s Disease. To conduct the study, researchers analyzed data from more than 935,000 patients ages 65 and older who received a flu shot versus an equal number of people who didn’t. Over a four-year period, those who had gotten at least one flu shot were 40% less likely to develop Alzheimer’s disease compared to unvaccinated participants.
Regular flu shots were also correlated with increased prevention of Alzheimer’s. The rate of developing Alzheimer’s was lowest among those in the study who consistently received the flu vaccine every year. Overall, 5.1% of flu-vaccinated participants developed Alzheimer’s disease over the study’s four-year period, versus 8.5% of patients who didn’t get the vaccine.
“We believe that the immune system is complex, and some alterations, such as pneumonia, may activate it in a way that makes Alzheimer’s disease worse. But other things that activate the immune system may do so in a different way — one that protects from Alzheimer’s disease.”
— DR. PAUL SCHULZ, A NEUROLOGY PROFESSOR AND ONE OF THE LEAD STUDY AUTHORS
Why does the flu shot impact Alzheimer’s disease?
Alzheimer’s disease affects more than six million Americans, according to the research from UT Health, and this isn’t the first study to demonstrate a link between annual flu shots and a decreased risk of developing the disease. In 2020, a separate study from UT Health found people who receive at least one flu vaccine are 17% less likely to develop Alzheimer’s disease over the course of their lifetimes.
The latest study is a follow-up to that previous research, but experts haven’t yet identified the reason why flu vaccines may reduce the risk of Alzheimer’s. Dr. Paul Schulz, a neurology professor and one of the lead study authors, says in a press release that the result may not be isolated to only the flu shot.
“Since there is evidence that several vaccines may protect from Alzheimer’s disease, we are thinking that it isn’t a specific effect of the flu vaccine,” Schulz says. “Instead, we believe that the immune system is complex, and some alterations, such as pneumonia, may activate it in a way that makes Alzheimer’s disease worse. But other things that activate the immune system may do so in a different way — one that protects from Alzheimer’s disease.”
Prior studies have also found links between the pneumonia vaccine, as well as other common adulthood vaccines, and a reduced risk of developing Alzheimer’s disease.
Are there other benefits to getting a flu shot?
In addition to possibly lowering the risk of Alzheimer’s, getting an annual flu shot also has other health benefits. According to the Centers for Disease Control and Prevention (CDC), getting yearly flu vaccines may:
- Reduce the risk of flu-associated hospitalization.
- Decrease the incidence of cardiac events among people with heart disease.
- Reduce hospitalizations in people with diabetes and chronic lung disease.
- Reduce the risk of flu-related chronic lung disease.
Despite these benefits, only about half of Americans get an annual flu shot.
More research is needed to determine the exact role vaccines play in preventing Alzheimer’s and other chronic illnesses, but the benefits of getting an annual flu shot continue to grow. On June 30, the CDC recommended a specific, higher dose flu vaccine for those 65 and older. Older adults are encouraged to talk with their doctors and get vaccinated for the flu to increase their chances of staying healthy.
