[chasil]

It appears that the first mention of scrapie in scientific literature is 1755, and the disease increased with inbreeding (and lessened when this practice was stopped):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1114482/

The wiki also indicates that a sheep vaccine distributed in 1935 caused an epidemic, as it contained contaminated neural tissue:

https://en.wikipedia.org/wiki/Scrapie

It also seems to me that the recent mRNA vaccines could be repurposed to target a section of a prion, so the immune system could clean them from the blood. An interesting question would test mRNA vaccine effectiveness in the cerebrospinal fluid, where microglia would be required to perform this function, as macrophages (and friends) are not present there.

[eximius]

This is a very interesting idea! But, is it known that macrophages are able to break down prions? My understanding of the problem is that part of it is that they're just quite hardy.

[chasil]

Even if they can't, it's probably better for them to build up in macrophages, dendritic cells, etc. rather than in neurons.

[dnautics]

Disagree. Every single antibody alzheimer's drug that has targeted the amyloid plaques and none of them have succeeded.

You're just as likely to elicit an immune response to the prion plaques, stabilize them, and recruit inflammation to the point of deposit, making matters worse.