Is an Alzheimer’s Disease Vaccine Possible?

Medically Reviewed by Christopher Melinosky, MD on January 20, 2024
4 min read

Current Alzheimer’s disease medications can help with some of the condition’s symptoms. Both aducanumab (Aduhelm) and lecanemab (Leqembi) have shown success in slowing the progression of the disease if treated early.  But, so far, there is no cure for the disease, although clinical trials continue in hopes of a new vaccine that can treat, cure, and prevent Alzheimer’s disease.

Recent studies have shown that older adults who have received certain vaccines appear to have a lower risk of developing Alzheimer’s. They include the shingles (HZV) vaccine Zostavax, tetanus and diphtheria, with or without pertussis vaccine (Tdap/Td), and the vaccine for pneumococcus. Vaccines to specifically target the prevention and treatment of Alzheimer’s are still in development.

If you have Alzheimer’s disease, you’ll probably have a buildup of tau proteins, beta-amyloid plaques, and inflammation in your brain and spinal cord.

Because these are the three most common signs of the condition, experts often study them during vaccine trials. The goal is to create vaccines to target these symptoms and slow down or prevent Alzheimer’s disease.

Each vaccine will focus on a specific symptom:

Tau protein vaccines. Tau proteins are in your brain cells, or neurons. Normal tau proteins help form part of a structure that experts call a “microtubule.” These help move nutrients and other important things from one area of your nerve cells to another.

But if there are changes in the tau protein, it can create neurofibrillary tangles. This is a common feature of Alzheimer’s disease. Abnormal tau will continue to build up as your Alzheimer’s disease gets worse. This usually starts in areas of your brain called the entorhinal cortex and hippocampus.

Tau will spread through your brain. If you have more tau buildup in your brain, your Alzheimer’s disease will probably be a later stage and be more severe.

Experts continue to study some vaccines that stop this process. This may be able to prevent Alzheimer’s from getting worse. Vaccines in clinical trials that use tau include:

  • AADvac1
  • ACI-35.030/JACI-35.054

Beta-amyloid vaccines. These proteins come in many forms. They come from the breakdown of a larger protein, which experts call amyloid precursor protein. These will collect between your neurons.

If abnormal amounts of these proteins clump together between neurons, it’ll mess with the proper function of your cells.

Experts know this can be part of the development of Alzheimer’s disease, but they aren’t exactly sure how.

Beta-amyloid vaccines are also in clinical trials. They include:

  • AC-1959D
  • ACI-24.060
  • ALZ-101
  • ABvac40
  • UB-311

Vaccines that target inflammation. Experts believe that inflammation in Alzheimer’s disease could be due to the buildup of glial cells. These cells are usually supposed to keep your brain free from debris. Microglia, a type of glial cell, takes in and destroys toxic material and waste in a healthy brain.

But if you have Alzheimer’s disease, your microglial cells won’t clear these unneeded materials or protein buildups (such as beta-amyloid plaques). Experts know this happens if you have Alzheimer’s, but they aren’t sure why the microglia fail with this disease.

Researchers continue to look at one gene called TREM2. This gene is supposed to tell microglia cells in your brain to get rid of beta-amyloid buildup. This also is meant to fight inflammation in your brain. But with Alzheimer’s disease, this doesn’t happen. Instead, plaques build up between neurons.

Another type of glial cell, which experts call astrocytes, help clear out the buildup of plaques and other cell debris. With the disease, microglia and astrocytes collect around your neurons instead and don’t do their job properly. They also give off chemicals that lead to constant inflammation and can harm your neurons instead of protecting them.

There are many ways to target inflammation. Immune-modulating vaccines use your immune system to treat diseases. These may be an option to help with inflammation. Vaccines in this category that are currently under clinical trials include:

  • Bacillus Calmette-Guérin
  • CpG1018
  • GV1001
  • Protollin

It will likely be some time before you can receive an Alzheimer’s disease vaccine. All of the promising options are still in clinical trials.

Since they’re still in trials, experts don’t know which vaccine will have the best outcome yet. But so far, the immune-modulated GV1001 vaccine is furthest in clinical trials.

As of now, stick to Alzheimer’s disease treatments that your doctor recommends. When vaccines are safe to use, your health care team will let you know.  If you would like to be considered for taking part in a clinical trial, discuss your options with your doctor.