A Human TSE Vaccine?

If we could have a usable vaccine for cervid TSEs and nothing else came of this research, that would be a fantastic result, but there's more on the table. It might be possible to use the same principles to create vaccines for other TSEs, in cows, sheep and even in humans. We could halt the spread of CJD between humans via infected tissue and blood, which is currently a major worry. Because prions aren't actually alive they can't be killed, so autoclaving and other once-sufficient procedures for sterilizing surgical equipment didn't work.

The WHO recommended that surgical equipment used on prion-infected patients be incinerated, until an alternative cleaning strategy that breaks prions down chemically was developed. That's great for surgical equipment, but not so wonderful for blood, for instance, which obviously can't be chemically cleaned. As a result, the USA has strict restrictions on who can give blood, based on their probable exposure to TSEs in Europe and the UK. 

Add in the fact that we don't know how many people were exposed to TSEs during the 90s "mad cow" scare. Because TSEs can have incubation periods up to 40 years, we don't know how many cattle were carriers, or how many infected people have yet to show symptoms.

Again, that would in itself be fantastic news. But CJD, horrible though it is, is relatively rare in human beings. It occurs at a rate of about one case per million people per year. But there are diseases that cause similar symptoms and are much more common. And they largely proceed by similar processes. 

Hope For Alzheimer's?

Alzheimer's disease kills about half a million people every year, and affects about six percent of people over 65. It's a major killer but an even more major drain of quality of life. There's no really effective drug therapy - some things  work a little but nothing really halts or even significantly slows he progress of the disease, which is characterised by brain shrinkage and the presence of amyloid plaques in the brain.

The development of amyloid plaques has been suggested as the underlying cause for Alzheimer's. But amyloid plaques show up in the brains of people and animals with TSEs too.

It's possible. The vaccine works by controlling the entry of prions into the body via the gut, though, rather than addressing the issue of amyloid plaques directly. And these aren't fully proven to be the cause of Alzheimer's in any case — it could be a case of "post hoc ergo proctor hoc" ("after it, therefore because of it"). No-one has yet proven a cause for Alzheimer's.

See Also: New Alzheimer's Disease Treatment: The Search Is On

Vaccines based on the amyloid plaque hypothesis have been tried in mice and humans with disappointing results, while vaccines based on tau theory have also not produced good results, with one trial having to be abandoned. Until we have a vaccine that acts directly on the cause of degenerate neurological diseases, we don't have a solution, sadly.