Analysis of the Pfizer vaccine against COVID-19 identified two potential risk factors for inducing prion disease in humans.  … a concern that ubiquitous intracellular molecules could be activated to cause prion disease including Alzheimer’s disease, ALS and other neurodegenerative diseases. This concern originates due to potential for misuse of research data on the mechanisms by which certain RNA binding proteins like TDP-43, FUS and others can be activated to form disease causing prions… regulatory approval of the RNA based vaccines for SARS-CoV-2 was premature… the vaccine may cause much more harm than benefit.”

Classen, J Bart. COVID-19 RNA Based vaccines and the Risk of Prion Disease. Microbiology & Infectious Diseases. 18 January 2021. https://scivisionpub.com/pdfs/covid19-rna-based-vaccines-and-the-risk-of-prion-disease-1503.pdf.