The results of a new study show a relationship between the flu vaccine and dementia, indicating that getting the vaccine every winter can significantly reduce the risk of developing dementia.

According to the study, the vaccine reduced the chances of developing the incurable case by 14 percent, but this only concerns patients who received vaccine doses for at least six consecutive years.
Scientists believe that vaccines gradually strengthen the aging immune system, so much so that it can prevent the underlying damage to the brain that causes dementia.

There has been no significant progress in treatment decades, but scientists now believe that vaccines such as the flu shot could play an important role in reducing the number of patients.

Scientists from St. Louis University School of Medicine in the United States tracked nearly 70,000 people aged 60 or older, and monitored how many received a yearly flu vaccine and whether they developed dementia later.

The results, published in the journal Vaccine, revealed little difference between those who did not receive a vaccine and those who have been vaccinated annually for the past four or five years. But once they reached six or more years of age, the risk decreased by an average of 14%.

Scientists said there was no indication that influenza infection causes dementia. Instead, the benefit comes from getting a vaccine later in life.

Animal studies suggest that vaccines such as the flu shot increase the activity of immune system cells in the central nervous system that are responsible for repairing damage that can lead to dementia.

The scientists explained: “Influenza vaccines could be a cheap and low-risk way to intervene against dementia.”

Dr Rosa Sancho, from Alzheimer’s Research UK, described the findings as intriguing, adding: “Understanding why this happens is a stimulating avenue for further research.”