New studies show flu, pneumonia vaccinations may lower Alzheimer’s risk
Vaccinations are a simple way to help protect yourself from common viral and bacterial infections, which is why the Centers for Disease Control and Prevention recommends that everyone receive an annual flu shot. But new research suggests that an added bonus to these vaccines could be a reduced risk of Alzheimer’s.
Research announced at the Alzheimer’s Association International Conference® 2020 (AAIC®) last summer shows a relationship between influenza and pneumonia vaccinations and a lower risk of Alzheimer’s
. The findings, which are still preliminary and require more extensive research, shed new light on how infection and Alzheimer’s may be linked.
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 vaccine and Alzheimer’s risk specifically. To address this gap, researchers at the University of Texas Health Science Center at Houston decided to further investigate the flu vaccine link by studying a large American health record dataset.
"Our study suggests that regular use of a very accessible and relatively cheap intervention — the flu shot — may significantly reduce risk of Alzheimer’s."
After examining the health data of more than 9,000 individuals age 60 and above, researchers found that a single flu shot lowered Alzheimer’s prevalence within the study group by 17%. More frequent flu vaccination was associated with an additional 13% reduction in prevalence within the group.
Even looking at a smaller subset of data on 74-84 year olds, a population that has a higher risk of Alzheimer’s due to age, showed a benefit. Consistently receiving a seasonal flu shot decreased this group’s chances of developing Alzheimer’s by almost 6%.
“Our study suggests that regular use of a very accessible and relatively cheap intervention — the flu shot — may significantly reduce risk of Alzheimer’s,” says Albert Amran, a co-author of the study. “More research is needed to explore the biological mechanism for this effect — why and how it works in the body — which is important as we explore effective preventive therapies for Alzheimer’s.”
While the link is intriguing, scientists caution that much more research is needed before a definitive connection between vaccines and reduced Alzheimer’s risk can be made.
“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 all other dementia,” says Maria Carrillo, Ph.D., Alzheimer’s Association chief science officer. “This research, while early, calls for further studies in large, diverse clinical trials to inform whether vaccinations as a public health strategy decrease our risk for developing dementia as we age.”
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Separate research presented at AAIC from the Duke University Social Science Research Institute demonstrated a relationship between the pneumonia vaccination and Alzheimer’s risk. Researchers looked at health data from over 5,000 individuals age 65 and older who had been vaccinated against pneumonia and whether they were carriers of a genetic risk factor for Alzheimer’s.
They found that individuals who received the pneumonia vaccine between the ages of 65 to 75 had a 25%-30% reduced risk of developing Alzheimer’s. Those who were vaccinated and did not have the genetic risk factor reduced their risk of Alzheimer’s by up to 40%. This study also found that the total number of vaccinations against both pneumonia and the flu was associated with a lower risk of Alzheimer’s.
Exactly how vaccines could reduce risk of Alzheimer’s is currently unknown. But the repurposing of existing vaccines may be a promising approach to Alzheimer’s disease prevention that should be further investigated, Carrillo says.
“With the COVID-19 pandemic, vaccines are at the forefront of public health discussions,” Carrillo says. “It is important to explore their benefit in not only protecting against viral or bacterial infection but also improving long-term health outcomes.”
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