Herpes Simplex Virus Type 1 May Affect Risk for Alzheimer Disease

THURSDAY, May 22, 2025 (HealthDay News) — Herpes simplex virus type 1 (HSV-1) is associated with an increased risk for Alzheimer disease (AD) based on real-world data from the United States, according to a study published online May 20 in BMJ Open.

Yunhao Liu, from Gilead Sciences Inc. in Foster City, California, and colleagues conducted a matched case-control study involving patients with AD aged 50 years and older diagnosed between 2006 and 2021 identified from the IQVIA PharMetrics Plus claims database to examine the association between HSV-1 and AD. Controls were matched with individuals with AD on age, sex, region, database entry year, and health care visit numbers in a 1:1 ratio (344,628 AD case-control pairs).

The researchers found that 0.44 and 0.24 percent of patients with AD and controls, respectively, had a history of HSV-1 diagnosis. There was an association for HSV-1 diagnosis with an increased risk for AD (adjusted odds ratio, 1.80). Compared with those who did not use antiherpetics, patients with HSV-1 who used antiherpetics were less likely to develop AD (adjusted hazard ratio, 0.83).

“These findings place an even greater emphasis on viewing the prevention of herpesviruses as a public health priority,” the authors write. “Further research to determine whether suppression of neurotropic viruses can alter the natural history of AD and AD-related dementia is warranted based on the consistent observational studies.”

Several authors disclosed ties to the pharmaceutical industry, including Gilead Sciences, which funded the study.

Abstract/Full Text