Flu and pneumonia vaccinations found to reduce risk of Alzheimer’s

Research studies reported at the Alzheimer’s Association International Conference (AAIC) 2020 suggest that flu (influenza) and pneumonia vaccinations reduce risk of Alzheimer’s disease.

“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,” Maria Carrillo, Alzheimer’s Association chief science officer, told the Alzheimer’s Association.

The studies showed that at least one flu vaccination was associate with a 17% reduction in Alzheimer’s incidence and more frequent flu vaccination was associated with another 13% reduction in Alzheimer’s incidence. Vaccination against pneumonia between ages 65 and 75 reduced Alzheimer’s risk by up to 40% depending on individual genes and individuals with dementia have a higher risk of dying after infections than those without dementia.

“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 told the Alzheimer’s Association. “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.”

Albert Amran, a medical student at McGovern Medical School at the University of Texas Health Science Center at Houston, and a team investigated a large American health record dataset finding that the flu vaccine lowers the prevalence of Alzheimer’s.

In Amran’s report, people that received an annual flu shot had a lower risk of Alzheimer’s — translating to an approximately 6% reduced risk of Alzheimer’s disease for patients between the ages of 75-84 for 16 years. 

“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,” Amran told the Alzheimer’s Association. “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 researchers also found that 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.

Svetlana Ukraintseva, associate research professor in the Biodemography of Aging Research Unit (BARU) at Duke University Social Science Research Institute, and a 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 and up from the Cardiovascular Health Study.

“Vaccinations against pneumonia before age 75 may reduce Alzheimer’s risk later in life, depending on individual genotype,” Ukraintseva told the Alzheimer’s Association. “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 researchers found that the risk of developing Alzheimer’s was reduced by 25- to 30% with the pneumococcal vaccination between ages 65-75 after adjusting for sex, race, birth cohort, education, smoking and number of G alleles. 

Janet Janbek, a Ph.D. student at the Danish Dementia Research Centre, Rigshospitalet and the University of Copenhagen in Denmark, and her team used national health registry data to investigate mortality in Danish residents over age 65 who had visited the hospital with an infection. 

The researchers found that those with dementia and hospital visits for infection died at a 6.5 times higher rate compared with people who had neither — the rate of mortality was highest within the first 30 days following the hospital visit.

“Our study suggests that the health care system — as well as relatives of people with dementia — should have increased awareness of people with dementia who get infections, so they get the medical care they need. People with dementia require more specialized treatment even when their hospital visits are not directly due to their dementia but to what might appear to be an unrelated infection,” Janbek told the Alzheimer’s Association.

Janbek’s team also found that the mortality rates remained elevated for 10 years after an initial infection-related hospital visit for people living with dementia.

“Our study supports the need to investigate these relations even further; to find out why infections are linked to higher mortality in people with dementia, specifically which risk factors and biological mechanisms are involved. This will help advance our understanding of the role of infections in dementia,” Janbek told the Alzheimer’s Association.