Three new research studies released at the Alzheimer’s Association International Conference (AAIC) 2020 said seniors getting flu and pneumonia vaccinations were less likely to get Alzheimer’s disease.

The findings included that at least one flu vaccination was associated with a 17 percent reduction in Alzheimer’s incidence. More frequent flu vaccination was associated with another 13 percent reduction in Alzheimer’s incidence, the reports said.

Second, vaccination against pneumonia between ages 65 and 75 reduced Alzheimer’s risk by up to 40 percent depending on individual genes. And, finally, individuals with dementia have a higher risk of dying (six-fold) after infections than those without dementia (three-fold).

“With the COVID-19 pandemic, vaccines are at the forefront of public health discussions. It is important to explore their benefit in not only protecting against viral or bacterial infection but also improving long-term health outcomes,” said Maria Carrillo, PhD, Alzheimer’s Association chief science officer.

“It may turn out to be as simple as if you’re taking care of your health in this way—getting vaccinated—you’re also taking care of yourself in other ways, and these things add up to lower risk of Alzheimer’s and other dementias,” Carrillo said.

The new research, while early, calls for further studies in large, diverse clinical trials to inform whether vaccinations as a public health strategy decrease the risk for developing dementia as people age.
The Alzheimer’s Association said previous research has suggested vaccinations may have a protective factor against cognitive decline, but there have been no large, comprehensive studies focused on the influenza (flu) vaccine and Alzheimer’s disease risk, specifically.

To address this gap, Albert Amran, a medical student at McGovern Medical School at The University of Texas Health Science Center at Houston, and his team investigated a large American health record dataset (n=9,066).

Amran and his team found having one flu vaccination was associated with a lower prevalence of Alzheimer’s, and among vaccinated patients receiving the flu vaccine more frequently was associated with an even lower prevalence of Alzheimer’s. Thus people who consistently got their annual flu shot had a lower risk of Alzheimer’s. This translated to an almost 6 percent reduced risk of Alzheimer’s disease for patients between the ages of 75 and 84 for 16 years.

The researchers found the protective association between the flu vaccine and the risk of Alzheimer’s was strongest for those who received their first vaccine at a younger age. For example, the people who received their first documented flu shot at age 60 benefitted more than those who received their first flu shot at age 70.

And, the reports said, repurposing of existing vaccines may be a promising approach to Alzheimer’s disease prevention.

Svetlana Ukraintseva, PhD, associate research professor in the Biodemography of Aging Research Unit (BARU) at Duke University Social Science Research Institute, and team investigated associations between pneumococcal vaccination, with and without an accompanying seasonal flu shot, and the risk of Alzheimer’s disease among 5,146 participants age 65-plus from the Cardiovascular Health Study. The team also took into account a known genetic risk factor for Alzheimer’s—the rs2075650 G allele in the TOMM40 gene.

The researchers found that pneumococcal vaccination between ages 65 and 75 reduced risk of developing Alzheimer’s by 25 to 30 percent after adjusting for sex, race, birth cohort, education, smoking, and number of G alleles.

The largest reduction in the risk of Alzheimer’s (up to 40 percent) was observed among people vaccinated against pneumonia who were non-carriers of the risk gene. Total number of vaccinations against pneumonia and the flu between ages 65 and 75 was also associated with a lower risk of Alzheimer’s; however, the effect was not evident for the flu shot alone.

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