August 16, 2023

Science Daily/University of Texas Health Science Center at Houston

Prior vaccination against tetanus and diphtheria, with or without pertussis (Tdap/Td); herpes zoster (HZ), better known as shingles; and pneumococcus are all associated with a reduced risk for developing Alzheimer's disease, according to new research from UTHealth Houston.

A pre-press version of a study was published online recently in the Journal of Alzheimer's Disease. It was led by co-first authors Kristofer Harris, program manager in the Department of Neurology with McGovern Medical School at UTHealth Houston; Yaobin Ling, graduate research assistant with McWilliams School of Biomedical Informatics at UTHealth Houston; and Avram Bukhbinder, MD, an alumnus of the medical school. Paul E. Schulz, MD, the Rick McCord Professor in Neurology with McGovern Medical School, was senior author of the paper, which will appear in print in the Sept. 12 issue of the journal, Volume (95) Issue (2).

Alzheimer's disease affects more than 6 million people living in the U.S., with the number of affected individuals growing due to the nation's aging population.

The new findings come just over a year after Schulz's team published another study in the journal, which found that people who received at least one influenza vaccine were 40% less likely than their unvaccinated peers to develop Alzheimer's disease.

"We were wondering whether the influenza finding was specific to the flu vaccine. This data revealed that several additional adult vaccines were also associated with a reduction in the risk of Alzheimer's," said Schulz, who is the Umphrey Family Professor in Neurodegenerative Diseases and director of the Neurocognitive Disorders Center at McGovern Medical School. "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."

Researchers performed a retrospective cohort study that included patients who were free of dementia during a two-year lookback period and were at least 65 years old by the start of the eight-year follow-up period. They compared two similar groups of patients using propensity score matching, one vaccinated and another unvaccinated, with Tdap/Td, HZ, or pneumococcal vaccine. Ultimately, they calculated the relative risk and absolute risk reduction for developing Alzheimer's disease.

"This study underscores the pivotal role that large-scale, observational datasets play in biomedical research," Ling said. "It's particularly encouraging to observe consistent results across numerous large-scale health care databases."

"By leveraging modern data analysis models and the very large claims database subscribed by McWilliams School of Biomedical Informatics, we gained valuable insights into which vaccines may protect against Alzheimer's and potentially develop more effective prevention strategies," said Xiaoqian Jiang, PhD, a co-author on the study who holds the Christopher Sarofim Family Professorship in Biomedical Informatics and Bioengineering with McWilliams School of Biomedical Informatics.

https://www.sciencedaily.com/releases/2023/08/230816170628.htm