A new study from researchers at the University of Texas Medical Branch has found that individuals with a history of herpes simplex virus (HSV) infections face a significantly higher risk of developing dementia, including Alzheimer’s disease. The findings, published in the Journal of Alzheimer’s Disease, highlight a critical link between HSV-1, which primarily causes oral herpes, and HSV-2 infections, which cause genital herpes, and neurodegenerative disease progression. 

"Our study is the first to provide compelling, nationwide large-scale evidence that herpes simplex virus infections may be a significant risk factor for dementia," said Dr. Giulio Taglialatela, senior author and director of the Moody brain Health Institute at UTMB. "These findings underscore the need for more research into the mechanisms underscoring HSV contribution to cognitive decline and whether such mechanisms can be targeted as a preventive strategy against dementia." 

This first large-scale, nationwide cohort analysis uses electronic health records from more than 120 million patients in the U.S. to confirm that HSV infections are associated with an increased dementia risk across diverse populations. The findings reveal that individuals with HSV-1, HSV-2, or co-infections had up to 2.44 times higher odds of developing dementia compared to those without an HSV diagnosis. Men with HSV-2 were at a significantly higher risk than women. 

This research strengthens the infectious and neuroinflammatory hypothesis of dementia, which suggests that viral infections play a key role in triggering neurodegeneration. The findings also suggest that targeting the involved mechanisms could potentially help lower dementia risk in HSV-infected individuals. 

"Given the high prevalence of HSV infections, our study highlights the urgent need to investigate whether early screening for HSV-positive individuals could help delay or prevent dementia," said Katherine Araya, first author of the study and Ph.D. candidate in the Department of Pharmacology and Toxicology at UTMB. 

Researchers suggest further clinical trials to further support the therapeutic concept that antiviral drugs like acyclovir, commonly used to treat herpes infections, might also reduce the risk of cognitive decline in older adults. 

"Our findings open the door to new possibilities in dementia prevention and treatment,” Taglialatela said. “If future research confirms that therapies targeting the mechanisms can slow or reduce the risk of cognitive decline, we may have a new, accessible strategy to combat dementia. This could be a game-changer for millions at risk." 

Other authors of the paper include researchers Riley Watson, Kamil Khanipov, George Golovko at UTMB.