No Thanks, I'll Wait: An Alzheimer's vaccine is believed to be safer than previously thought. The problem is, how do you decide who to immunize against Alzheimer's? The diagnosis of Alzheimer's as it stands now, is really nothing more than what used to be called senile dementia. (Back in the days when "Alzheimer's" was reserved for presenile dementia.) Not everyone with dementia in old age has those tangled fibers the vaccine works against. There's no way to tell if they have them without opening up their brain (i.e. autopsy.) There's no good way to predict who is likely to develop them, either. Then, there's the fact that the fibers the vaccine is directed against also occur in normal brains:

They said the antibodies recognized AB in tangles, diffuse AB deposits and AB in blood vessels of the brain and were able to cross the blood-brain barrier, which suggests they might have the capacity to directly destroy plaques in the brain.

The antibodies did not, however, attack the longer form of AB that occurs in the nerve cells of healthy people as well as Alzheimer's patients.

The function of that type of AB is unknown, but healthy nerve cells can contain a lot of it. This selectivity is good news, because an attack on the longer form of AB could potentially result in complications.

If healthy nerve cells contain a lot of it, then I'll keep mine, thank you, and not risk it to a vaccine.