Alzheimer's vaccine stopped plaque and not dementia

However, it turns out that they are wrong. A new vaccine that prevented the build up of the plaque that is characteristics of the brains of people with Alzheimer's disease, did not prevent the accompanying dementia.

Research was carried out in Britain on 64 patients who were followed up for six years. Autopsies of seven patients who died during the course of the study showed that the plaque - beta-amyloid protein tangles - was not present in their brains. But all had dementia.

Experts say that this points to a major gap in our understanding of the disease. Scientists have never been sure if the plaque is a cause of the dementia, or just something associated with the brain changes that take place in the disease.