Flu and Pneumonia Vaccines May Help Protect Against Alzheimer’s Disease

Flu Shot Vaccine

August 18, 2020

As coronavirus continues to pose a threat, it may be particularly important to get a flu shot this year. Influenza remains a top 10 cause of death, particularly in older people, and experts caution that hospitals may be overwhelmed when the flu season hits this winter. Adults 65 and over are also advised to get vaccinated against pneumonia.

Now two new studies, presented at the Alzheimer’s Association’s International Conference, suggest that the flu and pneumonia vaccines may have an added benefit: Vaccination may lower your risk of developing Alzheimer’s disease.

The results are preliminary, and scientists aren’t sure why the vaccinations may have benefits for the brain. Flu and pneumonia are caused by viral and bacterial infections, which have not been proven to have a link to Alzheimer’s disease. But the findings offer further incentives to get regular vaccinations against these life-threatening ailments.

One study, which examined health records of more than 9,000 men and women, found that flu vaccination was associated with a 17 percent reduction in the incidence of Alzheimer’s disease. Getting frequent and regular yearly flu vaccinations was associated with another 13 percent reduction in Alzheimer’s incidence. The protective association appeared to be strongest for those who received their first vaccine at a younger age, for example, at age 60 versus 70.

“Our study suggests that regular use of a very accessible and relatively cheap intervention — the flu shot — may significantly reduce risk of Alzheimer’s dementia,” said study author Albert Amran, a medical student at McGovern Medical School at The University of Texas Health Science Center at Houston. “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.”

The other study, which looked at health records of more than 5,000 men and women who were part of a heart study, found that getting a pneumonia vaccination between the ages of 65 and 75 was associated with an up to 40 percent reduction in the risk of Alzheimer’s. The risk was reduced the most in those who did not carry genes that put them at increased risk of developing Alzheimer’s.

“Vaccinations against pneumonia before age 75 may reduce Alzheimer’s risk later in life, depending on individual genotype,” said study author Svetlana Ukraintseva, associate research professor at the Duke University Social Science Research Institute. “These data suggest that pneumococcal vaccine may be a promising candidate for personalized Alzheimer’s prevention, particularly in non-carriers of certain risk genes.”

The studies do not prove cause and effect. People who regularly get vaccinations, for example, may exhibit other lifestyle characteristics, such as getting regular exercise and eating a heart-healthy diet, that lower their risk for Alzheimer’s disease.

But the findings raise interesting possibilities that fighting infections may have benefits for brain health. It is possible that preventing infections, particularly from an early age, may protect against inflammation and other disease processes that can take a toll on the brain over many years.

A third study presented at the conference found that those with Alzheimer’s disease or other forms of dementia are at increased risk of dying from infections — including flu and pneumonia — than those without dementia. So vaccination may have lifesaving benefits in those who already have Alzheimer’s disease as well, by preventing these life-threatening viral and bacterial infections.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: Alzheimer’s Association International Conference, July 2020.


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