Written by Being Patient

As people age, they tend to become more vulnerable to infections like influenza. Research shows that getting one’s flu shot can protect against more than just the flu. 

In the last decade, scientists have found strong links between viral infections and neurodegenerative disease. Respiratory infections like the flu may increase the risk of developing dementia — scientists aren’t sure why but they think it has something to do with throwing the immune system off balance. 

Getting vaccinated can keep you from getting sick, and as a result lowers the risk of dementia. In 2020, three studies presented at the Alzheimer’s Association International Conference found that flu vaccinations and pneumonia vaccinations significantly reduce the risk of Alzheimer’s.

In one of the studies, researchers found that people who had received a flu vaccine were 17 percent less likely to develop Alzheimer’s. Those who received multiple flu shots were 30 percent less likely to develop the disease than people who didn’t get the vaccine.

A more recent study conducted in 2022 that involved 1.8 million cognitively-healthy adults found that people who do not get vaccinated against the flu have a 60 percent higher chance of developing Alzheimer’s or other dementias compared to those who get their flu shot.

“The strength of this protective effect increased with the number of years that a person received an annual flu vaccine,” said Dr. Avram Bukhbinder, the lead author of the study. “In other words, the rate of developing Alzheimer’s or other dementias was lowest among those who consistently received the flu vaccine every year.”

While it still isn’t clear exactly why the flu vaccine has been shown to reduce Alzheimer’s risk, the authors believe the flu vaccine might train the immune system to respond to beta-amyloid protein plaques — a key part of Alzheimer’s pathology. The flu vaccine might work to activate immune cells in a helpful way.

What about vaccines for Alzheimer’s disease?

Researchers are already working to create a vaccine specifically designed to help prevent Alzheimer’s. Vaxxinity recently completed Phase 2b trials of its beta-amyloid targeting vaccine, known as UB-311. The vaccine is FDA-fast-tracked and designed to train the immune system to recognize beta-amyloid aggregates and stimulate the clearance of beta-amyloid plaques.

Protollin’s nasal vaccine also aims to prevent Alzheimer’s, but through a mechanism that stimulates the immune system. FDA-approval has yet to be granted to any vaccine specifically aimed to prevent Alzheimer’s, but with nine vaccines under development, it may not be far off.