More and more, vaccines are being linked to a lower risk of dementia. From flu shots to the humble tetanus jab, experts are puzzled by these unexpected benefits.

A new hypothesis suggests that vaccines might train parts of our immune system previously thought untrainable, offering hope for preventing or treating dementia.

While we understand how vaccines work on a general level—priming our bodies against specific pathogens—they may also be fortifying our innate immunity. This part of the immune system is typically seen as non-specific and hard to train, but if it can learn to recognize specific threats, it could have profound implications for brain health.

If this idea holds up, it could provide a deeper understanding of our immune systems and open new avenues for treating or preventing dementia. It might also add another layer of benefit to vaccines, which already save millions of lives worldwide.