Alzheimer’s disease affects more than 6 million people living in the U.S., with that number continuing to grow due to the nation’s aging population. While there is no cure, many researchers are focused on identifying strategies for prevention. Now, a team of scientists from the University of Texas Health Science Center in Houston may have done just that—at least partially—through the use of vaccines. Not a specific vaccine, but several different common, unrelated, vaccines.
In June of 2022, a team led by Paul E. Schulz, MD, who is also the lead author of the current study, published research in the Journal of Alzheimer’s Disease showing that receiving at least one dose of the standard flu vaccine reduced the risk of developing Alzheimer’s by 40 percent among people over age 65.
“We were wondering,” says Schulz, “whether the influenza finding was specific to the flu vaccine.” So he and his team set out to determine whether there was any association between other vaccines and risk of developing Alzheimer’s disease. Their new research was published in the online version of the Journal of Alzheimer’s Disease in August and will be published in the print edition in September.
Schulz and his team performed a retrospective cohort study using Optum’s Clinformatics® Data Mart (CDM), a deidentified, HIPAA-compliant database of insurance claims. CDM contains information on claims filed by some 67 million people in all 50 states. Schulz’s team examined data on more than one million patients who had no history of dementia for two years prior to—and were at least 65 years old at the start of—an eight-year study period.
They then compared two similar groups of patients using propensity score matching, one vaccinated and another unvaccinated, with Tdap/Td (tetanus and diphtheria, with or without pertussis), shingles, or pneumococcal vaccine. Ultimately, they calculated the relative risk and absolute risk reduction for developing Alzheimer’s disease.
Their analysis showed that patients who received a Tdap/Td vaccine showed a 30 percent decrease in Alzheimer’s disease, while those who received the shingles or pneumococcal vaccine experienced a 25 percent and 27 percent reduced risk, respectively. For comparison, Schulz said, three new anti-amyloid antibodies used to treat Alzheimer’s have shown they slow disease progression by 25 percent, 27 percent, and 35 percent.
“This data revealed that several additional adult vaccines were also associated with a reduction in the risk of Alzheimer’s,” said Schulz. “We and others hypothesize that the immune system is responsible for causing brain cell dysfunction in Alzheimer’s. The findings suggest to us that vaccination is having a more general effect on the immune system that is reducing the risk for developing Alzheimer’s.”
“This research highlights how important it is for patients to have ready access to routine adult vaccinations,” said Kristofer Harris, RN, another of the study’s authors. “Over the last couple of years, the field of Alzheimer’s disease has vastly expanded, especially with the recent approval of anti-amyloid antibody medications by the FDA. However, those medications require costly infrastructure in order to be administered safely. Conversely, adult vaccinations are widely available and are already routinely administered as part of a vaccination schedule. Our findings are a win for both Alzheimer’s disease prevention research and for public health in general, as this is one more study demonstrating the value of vaccination.”