Scientists working in the US and Australia have made progress on a vaccine candidate that could prevent and, in some cases, even reverse, the onset of dementia, Alzheimer's, and other related diseases.

This could be a big deal in the treatment of these diseases, seeing as the new drug is able to specifically target the tau proteins and abnormal beta-amyloid that can build up and cause Alzheimer's.

Even better, it could be ready for human trials in as little as two to three years, according to researcher Nikolai Petrovsky from Flinders University in Australia.

"If we are successful in preclinical trials, in three to five years we could be well on the way to one of the most important developments in recent medical history," he said.

Petrovsky told 891 ABC that the antibodies in the vaccine candidate work like tow trucks turning up to remove proteins damaged by disease. Two separate potential vaccines, one for beta-amyloid and one for tau proteins, have been combined to form the new treatment.

The second tau vaccine candidate is the most recent to be discovered and is the most effective at reversing damage in the brain. The beta-amyloid one works best if it's given as a preventative measure for those at risk of dementia.

Combined, the two drugs are even more effective, based on recent tests carried out on groups of mice.

To put it another way, one part of the new vaccine focusses on what triggers Alzheimer's, and the other focusses on what makes it get worse.

"It could be used both to give people at a particular age, say 50 years of age when they are perfectly fine, to stop them developing dementia, but potentially also could be given to people at least in the early stages of dementia to actually try and reverse the process," explained Petrovsky.

Each year, 7.5 million new cases of Alzheimer's are diagnosed around the world, and with an ageing population and an increase in type 2 diabetes (a major risk factor for Alzheimer's) in western societies, the outlook is gloomy. Alzheimer's is the most common cause of dementia in the elderly.

While hundreds of compounds have been tested for their ability to stop dementia in recent years, only around 0.5 percent of these have been approved to help and alleviate the effects of the disease.

That's not a great success rate, and to help get it up, a state-of-the-art universal vaccine platform called MultiTEP has been put together to more effectively target the proteins that cause these types of problems in the brain.

Scientists from Flinders University worked in partnership with the Institute of Molecular Medicine (IMM) and the University of California, Irvine (UCI) in the US on the new formula.

Not only do MultiTEP-designed antibodies bind strongly to their targets, they also avoid creating potentially harmful responses from the body's immune system, according to the IMM's Michael Agadjanyan.

While we don't know yet if the drugs will be effective in humans – and it will be several years before we do – there's a lot of excitement over the potential for a vaccine that could stop a rapidly growing health problem in its tracks.

The results of the latest research have been published in Scientific Reports.