Humanized mice (with ACE2 receptors) given Covid S-protein vaccination. 95% developed spongiform encephalopathy (prion disease in brain) and dead within 2 weeks. Same thing happened with Rhesus monkeys. In a human time span, that's 18 months from vax to dead for 95% of recipients.
Carossino M, et al. Fatal neuroinvasion of SARS-C 1 oV-2 in K18-hACE2 mice is partially dependent on hACE2 expression. https://doi.org/10.1101/2021.01.13.425144
Philippens I, et al. SARS-CoV-2 causes brain inflammation and induces Lewy body 1 formation in macaques. https://doi.org/10.1101/2021.02.23.432474