Covid-19 can cause brain cells to ‘fuse’
qbi.uq.edu.au
qbi.uq.edu.au
This is a really really terrible news.
Also, I'm not sure how the coronavirus proper gets into the brain, but it seems likely it's through infecting some cell that crosses over, rather than directly getting past the blood-brain barrier. That's less relevant for the mRNA vaccines because A) mRNA doesn't replicate and B) the spike proteins that get produced mostly get chopped up before they can leave the cells (they're not budding off into viral envelopes after all.)
Also, nearly everyone in the world has had the real thing now - that's a lot more spike than the vaccines contain, orders of magnitude more.