Flu, Pneumonia Vaccination Tied to Lower Dementia Risk.
In a cohort study of more than 9000 older adults, receiving a single influenza vaccination was associated with a 17% lower prevalence of AD compared with not receiving the vaccine.
In addition, for those who were vaccinated more than once over the years, there was an additional 13% reduction in AD incidence.
In another study, which included more than 5000 older participants, being vaccinated against pneumonia between the ages of 65 and 75 reduced the risk of developing AD by 30%.
The subject of vaccines “is obviously very topical with the COVID-19 pandemic,” Rebecca M. Edelmayer, PhD, director of scientific engagement for the Alzheimer’s Association, told Medscape Medical News.
“While these are very preliminary data, these studies do suggest that with vaccination against both respiratory illnesses, there is the potential to lower risk for developing cognitive decline and dementia,” said Edelmayer, who was not involved in the research.
The findings of both studies were presented at the Alzheimer’s Association International Conference (AAIC) 2020, which was held online this year because of the COVID-19 pandemic.
Lower AD Prevalence
The influenza vaccine study was presented by Albert Amran, a fourth-year medical student at McGovern Medical School at the University of Texas Health Science Center at Houston.
The researchers used electronic health record data to create a propensity-matched cohort of 9066 vaccinated and unvaccinated adults aged 60 and older.
Influenza vaccination, increased frequency of administration, and younger age at time of vaccination were all associated with reduced incidence of AD, Amran reported.
Being vaccinated for influenza was significantly linked to a lower prevalence of AD (odds ratio [OR], 0.83; P < .0001) in comparison with not being vaccinated. Receiving more than one vaccination over the years was associated with an additional reduction in AD incidence (OR, 0.87; P = .0342).
The protection appeared to be strongest for those who received their first vaccination at a younger age, for example, at age 60 vs 70.
Amran has two theories as to why influenza vaccination may protect the brain. One is that vaccination may aid the immune system as people age.