Flu Shot Linked with 40% Lower Risk of Developing Alzheimer’s
Getting your annual flu shot can save you from getting sick during flu season, or at the very least, lessen the severity of your symptoms. It’s also known to lower the number of flu-related hospitalizations each year. A new study finds its benefits may go a bit further than that.
Researchers from UTHealth Houston investigated the link between the flu shot and Alzheimer’s incidence, finding that those who had received at least one flu shot were 40% less likely to develop Alzheimer’s over a four-year period, compared with those who had not been vaccinated. An early version of the paper was shared in the Journal of Alzheimer’s Disease ahead of its August 2 publication.
Dr. Avram Bukhbinder, first author and a recent alumnus of McGovern Medical School at UTHealth Houston, says, “We found that flu vaccination in older adults reduces the risk of developing Alzheimer’s disease for several years. The strength of this protective effect increased with the number of years that a person received an annual flu vaccine – in other words, the rate of developing Alzheimer’s was lowest among those who consistently received the flu vaccine every year. Future research should assess whether flu vaccination is also associated with the rate of symptom progression in patients who already have Alzheimer’s dementia.”
To conduct the study, the team looked at nearly 936,000 flu-vaccinated U.S. adults aged 65 and older, and the same number of unvaccinated patients. This built on prior UTHeath Houston research on a smaller number of patients. At four-year follow-up appointments on the most recent study, the team found that about 5.1% of flu-vaccinated participants had developed Alzheimer’s, compared with 8.5% of unvaccinated participants.
While the team says this shows strong evidence of a protective effect of flu vaccines against Alzheimer’s, it isn’t clear why this seems to be the case.
Dr. Paul Schulz, senior author and Rick McCord Professor in Neurology at McGovern Medical School, explains, “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. 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. Clearly, we have more to learn about how the immune system worsens or improves outcomes in this disease.”
The team says it may be interesting to see if the COVID-19 vaccine provides similar protection against Alzheimer’s in the years ahead.
