Developing new vaccines is extremely difficult, expensive, and time-consuming. However, this doesn’t stop researchers from trying.

One method that helps simplify the process is repurposing existing vaccines or medications. Therapeutics that are approved for use in humans have already cleared the hurdle of proving their safety.

When it comes to treating Alzheimer’s disease, as many as 39 percent of the interventions in development consist of repurposed therapeutics.

Some of the most common signs of Alzheimer’s disease include the buildup of:

  • beta-amyloid plaques
  • tau proteins
  • neuroinflammation (inflammation in the brain and spinal cord)

These are the prime targets for an Alzheimer’s disease vaccine. Researchers are working to find ways to use our immune systems to clear out these plaques and proteins and reduce inflammation.

The goal is to give a vaccine as soon as Alzheimer’s disease is identified in a person to slow or prevent the disease’s progression. As we continue to learn more about the disease, researchers hope to identify it before the start of symptoms by monitoring various biological markers.

Read on to learn more about the current state of research into a vaccine for Alzheimer’s disease.

There are several approaches that experts are taking to develop vaccines for Alzheimer’s disease. Some approaches target beta-amyloid plaques, while others focus on the tau protein, and others are immune modulators.

Below are the Alzheimer’s disease vaccines currently undergoing clinical trials.

Vaccine Phase Target Sponsor
ALZ-101 1 Beta-amyloid Alzinova AB
ABvac40 2 Beta-amyloid Araclon Biotech S.L.
UB-311 2 Beta-amyloid United Neuroscience Ltd. (Vaxxinity, Inc.)
AADvac1 1 Tau Axon Neuroscience SE
ACI-35.030/JACI-35.054 1/2 Tau AC Immune SA
Bacillus Calmette-Guérin 2 Immune-modulated Steven E Arnold
GV1001 3 Immune-modulated GemVax & Kael

Beta-amyloid vaccines

Many, but not all, people with Alzheimer’s disease will have a buildup of beta-amyloid plaques. It’s not clear exactly how these plaques lead to dementia. Vaccines targeting beta-amyloid plaques seek to train your immune system to recognize and remove these plaques.

Tau vaccines

Tau is a protein that typically helps keep your neurons (nerve cells) functioning properly, but if you have Alzheimer’s disease, then tau can bunch up in long tubes called neurofibrillary tangles (NFTs).

These tangles make it difficult for your neurons to work properly. Some vaccine candidates are designed to prevent the processes that allow NFTs to form.

Immune-modulating vaccines

Immune-modulating vaccines can either block or activate different parts of your immune system to treat the underlying disease. One example would be a vaccine to reduce neuroinflammation, which is associated with Alzheimer’s disease.

Your immune system is vast and complex, so there can be many approaches to using it to treat Alzheimer’s disease.

When a new drug, vaccine, or other intervention is being considered for wide use, it will usually go through clinical trials. Clinical trials are conducted in three stages, called phases.

These phases are generally done in order, with one phase concluding before the next phase begins. In between phases, experts will review the results to make sure it is safe to proceed to the next phase.

Before phase 1 begins, testing is usually done in laboratory models or in animal studies. But no matter how good the models are, they still need to be tested in humans.

Phase 1 trial

According to the Food and Drug Administration (FDA), phase 1 generally lasts several months and consists of 20 to 100 volunteers in good overall health.

The purpose of phase 1 trials is to determine the proper dosage and whether the treatment is safe. About 70 percent of drugs pass phase 1 and move on to phase 2.

Phase 2 trial

In phase 2, several hundred participants who have the condition, such as Alzheimer’s disease, are being treated. This phase can last from a few months to as long as 2 years.

Phase 2 trials are meant to gather more safety data and determine the side effects of the treatment. About one-third of drugs pass phase 2 trials and continue to phase 3.

Phase 3 trial

Phase 3 trials are the largest and the longest. They can have anywhere from 300 to 3,000 participants and can last from 1 to 4 years.

This phase is used to show whether a treatment is effective and also to find out if there are any rare or long-term effects that earlier trials may have missed. Between 25 and 30 percent of drugs pass phase 3 trials.

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The three phases of clinical trials. Infographic by Sophia Smith

While the research into Alzheimer’s vaccines is exciting, it’s important to keep emotions in check. The clinical trial process exists to keep people safe from harmful side effects, and it can take many years for a treatment to get through the approval pipeline.

With a handful of Alzheimer’s vaccines in phase 2 and 3 trials, an approval could be expected in the next 5 to 10 years. But that’s only if the vaccines prove to be both safe and effective. It’s likely that new potential vaccines will continue to enter the development pipeline in the foreseeable future.

Alzheimer’s disease is the sixth leading cause of death in the United States, which means that a safe and effective vaccine would get a lot of attention and might be eligible for a special approval process.

The FDA has many expedited approval processes, including Breakthrough Therapy and Accelerated Approval among others, which could help bring an Alzheimer’s vaccine to market more quickly.

Alzheimer’s disease currently has no cure, and more effective treatments are needed. One avenue that researchers are pursuing is Alzheimer’s vaccination.

A vaccine for Alzheimer’s disease could take many forms. It could focus on the:

  • beta-amyloid plaque
  • NFTs made of tau proteins
  • immune modulation

In all cases, the thinking is that your body’s immune system can be trained to detect and repair some of the mechanisms involved in Alzheimer’s disease. This could lead to a reduction or elimination of symptoms, including dementia.

For a vaccine to be most effective, doctors will need to detect Alzheimer’s disease early, before symptoms have become severe. This is still an active area of research.

Several Alzheimer’s vaccines are currently in various phases of clinical trials. If any are found to be both safe and effective, they could be made available in as little as 5 to 10 years.