Antiviral treatment associated with reduced risk of clinical Alzheimer's disease—A nested case‐control study

Introduction In this nested case‐control study, we investigated if antiviral treatment given prior to onset of Alzheimer's disease (AD) could influence incident AD. Methods From a large population‐based cohort study in northern Sweden, 262 individuals that later developed AD were compared to a non‐AD matched control group with respect to prescriptions of herpes antiviral treatment. All included subjects were herpes simplex virus 1 (HSV1) carriers and the matching criteria were age, sex, apolipoprotein E genotype (ε4 allele carriership), and study sample start year. Results Among those who developed AD, 6 prescriptions of antivirals were found, compared to 20 among matched controls. Adjusted for length of follow‐up, a conditional logistic regression indicated a difference in the risk for AD development between groups (odds ratio for AD with an antiviral prescription 0.287, P = .018). Discussion Antiviral treatment might possibly reduce the risk for later development of HSV1‐associated AD.