An experimental vaccine that could hold off Alzheimer's disease showed promising results in animal testing, according to researchers at the University of Texas Southwestern Medical Center.

Testing in mice showed that the vaccine safely prevents the buildup of substances in the brain associated with the fatal disease, the team reported this week in the journal Alzheimer's Research & Therapy.

There has been research in monkeys and rabbits as well, and the researchers hope the vaccine will progress to human trials.

Also see | Auburn couple shares story of Alzheimer's diagnosis and fight to find a cure

If the vaccine proves safe and effective in humans, it could slice the number of dementia diagnoses in half, the study's senior author told USA TODAY.

Dementia is a term used to broadly describe symptoms of cognitive decline; Alzheimer's disease is the most common cause of dementia.

Doris Lambracht-Washington, a professor of neurology and neurotherapeutics at the University of Texas Southwestern Medical Center, said researchers believe the vaccine could extend lives by preventing the disease from developing.

“If the onset of the disease could be delayed by even five years, that would be enormous for the patients and their families,” Lambracht-Washington said in a statement. “The number of dementia cases could drop by half.”

Lambracht-Washington said the study marks major progress toward a safe and effective vaccine.

Also see | Eyes could show risk of Alzheimer’s, UW study finds

Previous attempts to find an Alzheimer's vaccine either caused harmful side effects, such as brain inflammation, or used less effective approaches, she said.

The vaccine works by prompting the body to produce antibodies inhibiting the buildup of amyloid and tau, two proteins that are hallmarks of the degenerative brain disease.

The vaccine is one of several promising treatments aimed at reducing the buildup of those substances before they become deadly plaques and tangles in the brain.

About 5.7 million Americans have Alzheimer's disease, according to the University of Texas. The number could double by 2050.