Specifically, they showed increased levels of total tau, neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and ubiquitin carboxy-terminal hydrolase L1 (UCHL1) in the blood of neuro-COVID patients, which together indicated a profound neurological insult comparable to non-COVID patients with AD [269,270]. Here, NEFL is linked to Alzheimer disease.