Getting vaccinated against shingles could significantly reduce (by about 20% in relative risk) the risk of developing significant cognitive decline as one ages, an effect that is particularly marked in women.

noli's read

The creator correctly relies on a major observational study published in the prestigious journal Nature (2025) by researchers from Stanford University. This research uses a regression discontinuity method (a natural experiment), a type of high-quality observational evidence that mimics a quasi-randomized trial to rule out the healthy user bias. It effectively demonstrates a 20% relative reduction (3.5% in absolute value) in cognitive decline diagnoses over seven years. The distinction between men and women is scientifically accurate: the protective effect is driven almost exclusively by women, with the effect in men being close to zero. However, the study concerns the older live-attenuated vaccine (Zostavax), and it is not yet proven that these benefits apply in the same way to the current vaccine (Shingrix). Although this signal is extremely promising for long-term brain health, randomized clinical trials (RCTs) are still required to definitively confirm a causal link.

the sources

No named source held this one up — that absence is part of the verdict.