“Flu vaccination in older adults reduces the risk of developing Alzheimer’s disease over several years.”
New York-People who received at least one influenza vaccine were 40 percent less likely than their unvaccinated peers to develop Alzheimer’s disease over four years, according to a new study.
Research from the University of Texas Health Science Center, Houston, compared the risk of Alzheimer’s disease incidence between patients with and without prior influenza vaccination in a large sample of U.S. adults aged 65 and older nationwide.
“We found that influenza vaccination in older adults reduces the risk of developing Alzheimer’s disease over several years. The strength of this protective effect increased with the number of years a person received an annual influenza vaccine; in other words, the rate of developing Alzheimer’s was lowest among those who received the flu vaccine every year,” said Avram S. Bukhbinder, of the university team.
“Future research should assess whether flu vaccination is also associated with the rate of symptom progression in patients who already have Alzheimer’s dementia,” Bukhbinder added.
The study included 935,887 influenza-vaccinated patients and 935,887 unvaccinated patients.
During four-year follow-up appointments, about 5.1 percent of the influenza-vaccinated patients were found to have developed Alzheimer’s disease. Meanwhile, 8.5 percent of the unvaccinated patients had developed Alzheimer’s disease during follow-up.
These results underscore the strong protective effect of the flu vaccine against Alzheimer’s disease, according to Bukhbinder and his associates. However, the underlying mechanisms behind this process require further study.
“Given that there is evidence that several vaccines can protect against Alzheimer’s disease, we think it’s not a specific effect of the flu vaccine,” said Paul. E. b Schulz, a professor on the university team.
“Instead, we think the immune system is complex and some disturbances, such as pneumonia, can activate it in a way that worsens Alzheimer’s disease. But other things that activate the immune system may do so in a different way, one that protects against Alzheimer’s disease. Clearly, we have more to learn about how the immune system worsens or improves outcomes in this disease,” he said.
Previous studies have found a decreased risk of dementia associated with prior exposure to several vaccines in adulthood, including tetanus, polio, and shingles vaccines, in addition to flu and other vaccines.
In addition, as more time passes since the introduction of the covid-19 vaccine and longer follow-up data become available, Bukhbinder said it will be worth investigating whether there is a similar association between covid-19 vaccination and the risk of Alzheimer’s disease.