People who have received at least one dose of the flu vaccine are 40% less likely to develop Alzheimer’s disease over four years, according to a new research.
The study, signed by scientists at the University of Texas Health Sciences Center, in Houston, compared the risk of disease incidence between people with and without previous vaccination against influenza virus in nearly two million people aged 65 and older. In addition to the good sample, the study also has a good interval, comprising a decade, between 2009 and 2019.
Vaccination against influenza in older adults “reduces the risk” of developing Alzheimer’s over several years, and this possible protective effect increases with the number of years a person has received an annual vaccine, said one of the study’s signatories, Avram Bukhbinder, in a statement.
The researchers considered that future research should assess whether this vaccine is also associated with the rate of symptom progression in patients who already have Alzheimer’s dementia.
Previous studies have already found a decreased risk of dementia associated with previous exposure to several vaccines in adulthood, including tetanus, polio and herpes, in addition to influenza and other vaccines.
The study, published in scientific journal
Journal of Alzheimer’s Disease, analyzed two paired groups, each formed by 2009.887 people, one vaccinated against the flu and the other not.
The participants were followed up for four years and in the follow-up consultations it was found that about 5.1% of the patients vaccinated against the flu developed the Alzheimer’s disease, compared with 8.5% of the unvaccinated.
These results, according to the team, “highlight the strong protective effect of the flu vaccine also against Alzheimer’s disease. However, the mechanisms underlying this process require further study.”
Leader of the study, Paul Schulz, stated that “since there is evidence that several vaccines can protect against the disease disease, we think that this is not a specific effect of the flu vaccine”.
The immune system is complex, and some disorders, such as pneumonia, can activate it in a way that worsens the Alzheimer’s disease, but others can do it differently, and one of them protects against that disease, he added.
“Clearly,” he said, “we need to learn more about how the immune system gets worse. or improves the results of this disease.” Different studies have already associated a lower risk of Alzheimer’s with various habits, such as drinking coffee and exercising intellectually. It is important to note that these studies, including Schulz’s, point to things that occur together, without compromise with the causal relationship between them. The habit of taking vaccines in a elderly may be correlated with other characteristics that would be the true causes of the protective effect.
In addition, as more time passes since the introduction of the Covid vaccine-19 and as more follow-up data become available, Bukhbinder said it would be worth investigating whether there is a similar association between it and the risk of Alzheimer’s disease. It is important to note that, of the vaccines produced and used on a large scale against Covid, only Coronavac uses the traditional technology that is also used in the annual flu vaccines.
What exactly causes Alzheimer’s is still a mystery, as much as the mechanisms of cause and consequence in habits and treatments that can lower the risk of developing it. One hypothesis under consideration is that people who develop this type of dementia, which affects memory, have a malfunction of a brain protein known as amyloid beta.