New Delhi: For years, doctors and researchers worldwide noticed something curious. Older adults who regularly got certain vaccines, like the flu shot or shingles vaccine, seemed to stay sharper as they aged. Their memories held up better, and they were less likely to be diagnosed with dementia, including Alzheimer’s disease. At first, the idea raised eyebrows. How could a simple vaccine meant to prevent an infection have anything to do with the brain?

But as study after study uncovered similar patterns, the medical community began to take notice. Today, m ore evidence than ever points to a link between routine vaccinations and a lower risk of cognitive decline.

This realisation has sparked two major lines of inquiry. One focuses on the numbers—large-scale studies an

See Full Page