Researchers have found that older adults who receive a high-concentration flu vaccine may be up to 55% less likely to develop Alzheimer's, compared to a 40% reduction in those who receive the regular vaccine.
The study included nearly 200,000 people aged 65 and older. Its findings, published in the journal Neurology, add to growing evidence suggesting that routine vaccinations may help protect the brain as we age.
This doesn't mean that getting the flu directly causes dementia. Rather, scientists believe the benefit comes from the vaccination itself later in life. As we age, our immune system weakens and becomes less able to fight off infections, and chronic inflammation in the body increases—a major driver of brain cell damage associated with dementia. At the same time, cells become less able to repair themselves, increasing the risk of developing diseases like cancer and heart disease, in addition to dementia.
This is where vaccines, especially high-dose ones, come in. They may help strengthen the immune system in older adults and reduce inflammation, which in turn lowers the risk of dementia. The protective effect was stronger in women, although the reason for this is still unclear.
Dr. Paul Schultz, a professor of neuroscience at the University of Texas, explains that the immune system becomes less effective at fighting infection at age 65, which is why the high-concentration vaccine is recommended for this age group, as it is four times stronger than the regular vaccine.
Dr. Avram Bukhbinder of Massachusetts General Hospital adds that choosing a high-concentration vaccine may be an easy, safe, and accessible way for everyone to help protect the brain as we age.
It's important to note that this study was observational, meaning it shows an association between the vaccine and a reduced risk of Alzheimer's, but it doesn't provide conclusive evidence that the vaccine directly protects against it. Other factors, such as the overall health and lifestyle of older adults, could also influence the results.
