Vaccinating Against Alzheimer's?

"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."

"More research is needed to explore the biological mechanism for this effect -- why and how it works -- which is important as we explore effective preventive therapies for Alzheimer's."

"There has been a concern in the medical community that many sources of inflammation, such as urinary tract infections, worsen the course of patients with Alzheimer's disease."

"Hence, we have been worried that vaccinations, a form of inflammation, could also worsen the course of AD."

"We were very surprised, because of the concern noted above about the potential to increase AD, when our statistical colleagues told us that the flu vaccination was one of the 'medications' that is so strongly associated with a lower Alzheimer's incidence."

Albert Amran, researcher, McGovern Medical School, University of Texas Health Science Centre, Houston

"[The link between a flu shot and reduced dementia risk is] intriguing."

"This study indicates there is a benefit of having one flu vaccination on dementia risk."

"It is difficult to speculate on the reasons behind this link, and understanding why a seasonal flu vaccine is linked to reduced dementia risk is an important avenue for further research."

"This research does not mean that Alzheimer's disease is caused by the common flu and there are potential non-biological explanations for this association, such as people who get the flu vaccine being more likely to take other steps to protect their health."

Dr.Rosa Sancho, Alzheimer's Research UK

"This is an encouraging finding that builds upon prior evidence that vaccination against common infections diseases -- such as the flu -- is associated with a reduced risk for Alzheimer's and a delay in disease onset."

"Regular use of the flu vaccine, especially starting at an early age, may help prevent viral infections that could cause cascading effects on the immune system and inflammatory pathways."

"These viral infections may trigger Alzheimer's related cognitive decline."

Dr. Richard Isaacson, neurologist, founder, Alzheimer's Prevention Clinic, New York-Presbyterian and Weill Cornell Medical Center

"We do need more research to understand what that connection is."

"Is it direct, the vaccine to disease? Or is it protective, as a part of the risk reduction strategies that we have, like lower your BMI [body mass index], watch your sugar intake, keep an eye on your cholesterol and high blood pressure, exercise, get vaccinated."

"It's one of those sort of health tips that we need to make sure that our public knows about."

"We've always known that vaccines are very important to our overall health. And maybe they even contribute to protecting our memory, our cognition, our brain."

Maria Carrillo,  Alzheimer's Association chief science officer

Several lines of evidence now suggest that two common vaccines against respiratory illnesses can help protect against Alzheimer's, too. How much brain protection they offer will require more intensive study to quantify, scientists say. Themba Hadebe/AP

According to research presented at the Alzheimer's Association international conference, an inoculation against flu has the potential to reduce dementia risk by close to a fifth. This, according to a study suggesting that vaccinating people while they're in their relatively younger years could prove to be beneficial in this regard.

The conference also heard that infections in dementia patients could increase death risk seven-fold. While the University of Texas study suggests flu vaccination could reduce dementia development by 17 percent. Bad news/good news.

The protective association between flu vaccine and the risk of Alzheimer's came out of a study of 9,000 people. The reduced risk of Alzheimer's associated with the flu vaccine was greatest in the instances of those receiving their first vaccine at a younger age as compared to those whose first documented flu shot was at age 70. Those of age 60 saw greater benefit accruing to them than their counterparts a decade older.

Research by the University of Copenhagen involving 1.5 million people suggests that people suffering from dementia have a 6.5-fold risk of dying after contracting any infection. Over half the the British population is scheduled to be offered inoculations free of charge in an effort to ensure the National Health Service will be able to cope should there be a second coronavirus wave.

Bearing in mind that complications related to COVID risk increase with age.

The Alzheimer's association pointed out that people with dementia had been infected in great numbers by COVID-19. The irony in the presentation of these findings is that it had generally been assumed previously that vaccination was implicated in Alzheimer's onset.

"We [tried] to make sure that both groups [in the controlled study] had an equal amount of, say, smoking status, obesity, diabetes, cardiovascular disease [known risk factors for Alzheimer's]", pointed out Dr.Amran. Factors such as education and income, along with indicators like the number of prescriptions a person had been prescribed, in an effort to ensure that people who received vaccines weren't just healthier overall were also investigated. As it turned out, they weren't.

Flu Vaccination : Protecting Mother and Baby

"This is a large study and it clearly shows that there were no harmful effects on the longer-term health of children when a pregnant woman got the flu shot."
"Influenza vaccination during pregnancy is -- by all available evidence -- safe for mothers and their offspring."
"This is really important because we know that getting the flu shot in pregnancy reduces women's chance of getting the flu -- and they're a high-risk group."
"But it also can prevent influenza in babies in the first few months of life, which is when they're particularly vulnerable but can't be vaccinated."
"I think most people when they think of getting the flu shot, they think of preventing the flu in themselves -- and that's already a compelling enough reason. But the big thing here is that it has the additional bonus of protecting the babies."
"I think it adds to the evidence, which has been growing rapidly in the last five years, that there's no harmful effects to getting vaccinated against influenza -- either for the mothers or babies."
Dr. Deshayne Fell, scientist, CHEO Research Institute

According to the Centers for Disease Control and Prevention, about 49 percent of pregnant women in the U.S. opted to get a flu shot during the 2017-2018 flu season.  Photo: Getty Images

An average of 3,500 deaths annually is attributed to the flu in Canada, according to the Public Health Agency of Canada, with most of those deaths occurring among the elderly and infirm. Roughly 36 percent of adults take advantage of a yearly flu vaccine. And although the primary age group for flu-related deaths is the elderly, the infirm, the immunity-impaired, young children as well represent a demographic with a high mortality rate from the flu. Infants under 6 months cannot be vaccinated.

Pregnant women in Canada mostly avoid getting a flu shot; a mere 20 percent opt for it, with research indicating avoidance of vaccination in pregnancy occurs resulting from safety concerns among pregnant women. Now, Dr. Fell, an assistant professor at University of Ottawa School of Epidemiology and Public Health, has responded to those concerns through the result of a study she headed along with other researchers.

She is able to assure pregnant women that the flu vaccine offers protection both to a mother and her baby against influenza, given that maternal antibodies cross the placenta. These are antibodies that confer protection -- passive immunity -- during the critical first six months of a child's life. The study was published in the BMJ (British Medical Journal). Researchers at the Research Institute of the Children's Hospital of Eastern Ontario had a goal; to determine whether vaccination of an expectant women would play a role in health outcomes of children during the first five years of their lives.

Disease and hospitalization rates for 104,000 children born in Ontario between November 2009 and October 2010 -- during the swine flu (H1N1) pandemic were tracked by the researchers. The 31,295 children born to mothers who received the flu vaccine were found to be just as healthy as the 79,954 children whose mothers failed to take a flu shot. The province's health databses were used by researchers to link birth registry information with hospital records.

Flu-related death rates among children are highest for those under six months, when an infant's immune system is still being developed, according to health statistics. The study gave evidence that children of vaccinated mothers were not afflicted with higher rates of death, cancer, serious infections, chronic diseases, sensory disorders, hospital admissions, or emergency room visits.

A slightly higher rate of asthma was detected among the same cohort, along with a slightly lower rate of serious gastrointestinal infections. No biological mechanism to explain the weak link between a mother's immunization and a child's asthma, however. was uncovered. The new study, adding to existing scientific literature indicating the flu vaccine has no negative short-term health effects on mothers or their infants is important as a guiding reassurance to both health professionals and their patients.

"This is an important decision for pregnant women because if they or their newborn babies get the flu, they generally get sicker than the rest of the population."
"We hope the knowledge that the flu shot during pregnancy is safe for children in the longer term will lead to more pregnant woman saying yes to the flu shot."
Dr. Deshayne Fell, study senior author

An Ottawa study shows no increased risk for various diseases in children whose mothers received the H1N1 flu vaccine while they were pregnant. (Jeff McIntosh/Canadian Press)