For decades, the medical establishment has poured billions of dollars into finding a cure—or even a meaningful treatment—for Alzheimer’s disease and related dementias. The results have been largely disappointing. But a growing body of research is now pointing toward an unexpected and remarkably accessible intervention: the shingles vaccine. Multiple studies, drawing on vast population-level data from several countries, suggest that vaccination against herpes zoster may reduce the risk of dementia by a significant margin, raising profound questions about the underlying causes of neurodegeneration and the future of preventive medicine. The latest evidence, as reported by Ars Technica , continues to strengthen the case. What began as an intriguing epidemiological observation has evolved into a serious scientific hypothesis backed by data from millions of patients across the United States, the United Kingdom, and Scandinavia.…