After repeated blows simulating a concussion activated the dormant HSV-1 within the brain organoid samples, a significant build-up of amyloid plaque and tangles of tau protein — key markers of Alzheimer’s disease — was detected. The effect was not observed in uninfected samples.

The study was led by Tufts and Oxford researchers and published in Science Signaling:

Dana M. Cairns et al. Repetitive injury induces phenotypes associated with Alzheimer’s disease by reactivating HSV-1 in a human brain tissue model. Sci. Signal.18, eado 6430 (2025).

https://science.org/doi/10.1126/scisignal.ado6430