A vaccine aimed at reducing brain plaque didn't help cure Alzheimer's disease, researchers have found. The results of the five-year study disappointed scientists who believed that cutting down plaque levels in the brain would help reduce the symptoms of Alzheimer's.

The new research, led by Clive Holmes of Moorgreen Hospital in Southampton, looked at 80 patients with mild to moderate dementia. Researchers used amyloid-beta peptide on patients' brains to clear the plaque but results indicated that it didn't help patients live longer or slow the disease's progression.

Seven of the eight immunized patients, including those with virtually complete plaque removal, had severe end-stage dementia before death.

The study was funded by the Alzheimer's Research Trust and published in The Lancet.

Alzheimer's is a neurodegenerative brain disease that affects 18 million people around the world. It is the most common form of dementia. Current drugs temporarily ease symptoms of the mind-robbing disease without slowing it.