Columbia University Irving Medical Center Jul 30 2025 The idea that herpes infections trigger or contribute to Alzheimer's disease has been gaining favor among some scientists, raising hope that herpes treatments could slow progression of Alzheimer's symptoms among patients.  But the first clinical trial to test that theory has found that a common antiviral for herpes simplex infections, valacyclovir, does not change the course of the disease for patients in the early stages of Alzheimer's.