The risk of developing dementia increases as a person ages. According to the National Institute of Health (NIH) the risk of dementia was 4% by the time a person is 75, and 20% by age 85, and even higher after 85 years of age. Thus the interest in ways to prevent the onset of dementia, including Alzheimer's disease.
One way to lower the risk of Alzheimer's disease is getting vaccinated, including the shingles and flu vaccines, after the age of 60. A recent study found that getting vaccinated with high dose flu vaccines in adults 65 years and older (instead of standard dose) reduces the odds of developing Alzheimer's disease even more.
A possible reason for the protective effect of the flu vaccine, especially the high-dose vaccine, is that vaccination strengthens immune defenses and reduces inflammation. Inflammation is thought to play a role in the development of Alzheimer's disease.
Excerpts from CIDRAP: High-dose flu vaccine tied to lower Alzheimer’s risk in older adults
Receiving a high-dose flu vaccine is associated with a significantly lower risk of Alzheimer’s disease than a standard-dose vaccine in adults aged 65 and older, according to a large observational study published in Neurology. The findings add to a growing body of evidence linking vaccination, and possibly immune system activity, to reduced dementia risk.
In the retrospective cohort study, researchers led by a team at the McGovern Medical School at UTHealth in Houston analyzed health data from roughly 165,000 older adults who received either a high-dose or standard-dose influenza vaccine. The researchers found that the high-dose flu vaccine reduced the risk of Alzheimer’s disease in those 65 and older by nearly 55% over a roughly two-year period.
Previous findings by the same research team found the standard-dose vaccine was tied to a 40% reduced risk of developing Alzheimer’s over a four-year period.
The high-dose influenza vaccine contains four times the antigen (the component that generates an immune response) of standard-dose vaccines. The Centers for Disease Control and Prevention recommends that all adults 65 years and older receive the high-dose vaccine.
Previous research has suggested that men and women respond differently to vaccines. In this study, both men and women had a lower risk of Alzheimer’s disease after receiving the high-dose flu vaccine compared with the standard-dose version, but the effect appeared to last longer and be more consistent in women.