As cases pile up (445 as of July 9) of the reportedly "rare" neurological disorder Guillain-Barré syndrome in people who received a COVID vaccine — forcing the sluggish U.S. Food and Drug Administration (FDA) to add a warning label to the Johnson & Johnson (J&J) shot — scientists are issuing urgent warnings about a possible tsunami of other types of neurological injuries.

Immunologist J. Bart Classen, one-time National Institutes of Health (NIH) contract scientist and proprietor of Classen Immunotherapies, a Maryland biotechnology firm, published a paper in February outlining the potential for messenger RNA (mRNA) COVID vaccines to trigger development of prion diseases as well as other chronic diseases.

Prion or "prion-like" diseases include Alzheimer's, Parkinson's, amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA) and others. A hallmark of these neurodegenerative diseases is the formation and clustering of misfolded proteins within the nervous system.