Will we ever have a vaccine to prevent Alzheimer’s disease?

There are currently nine trials of vaccines for Alzheimer’s disease under way. All of them are in people with mild Alzheimer’s or with the pre-Alzheimer’s condition called mild cognitive impairment. All of the vaccines are designed to encourage the immune system to remove protein deposits from the brain. Most experimental vaccines are given by injection; one being tested at Harvard Medical School uses a nasal spray. It will be several years before we know if any of them will work.