A study of 227 individuals who experienced neurocognitive difficulties post COVID-19 infection—such as headaches, vertigo, balance dysregulation, changes in taste/smell, and brain fog—displayed a significant increase in their blood plasma of a crucial protein called tau, which is found in nerves and especially in the brain. Excess levels of tau are linked to neurodegenerative diseases and found in many Alzheimer’s patients.

Published in eBioMedicine, the study suggests that people who experience long COVID neurocognitive symptoms could be at further risk for neurodegenerative diseases.