Could a dementia vaccine be on the way?

There’s a lot that’s still not known about dementia, but recent research by scientists at the University of Colorado Anschutz Medical Campus in the US could potentially lead to a vaccine against the neurodegenerative disease. It focused on viral infections as an aggravating factor in the development of Alzheimer’s and how they could be prevented.

Among the viruses identified as possibly leading to a higher risk of Alzheimer’s were herpes simplex virus type 1 (HSV-1, which causes cold sores), varicella zoster virus (VZV, which causes chickenpox and shingles) and SARS-CoV-2 (which causes COVID-19), reports The Conversation.

If scientists can establish how and when these viruses contribute to the development of dementia, it could form the basis of new prevention therapies. The biggest challenge at present is to consistently detect these viruses in the brains of deceased Alzheimer’s patients.

This is thought to be because the viruses that trigger the events leading to dementia have disappeared by the time symptoms start to appear. As researchers usually analyse these brains decades later, there are no detectable viral components left to demonstrate causation.

Now, the team in Colorado, which consists of neurovirologists, neurologists and neuroscientists, is looking to investigate this further. They are utilising new technology to find any suggestion in Alzheimer’s patients that these viruses have been present.

Much of their work has focused on the nose, which is the most vulnerable entry point to the brain. Here, they have been able to detect a genetic network that shows when a robust viral response has taken place.

Lots of the viruses thought to be associated with dementia interact with the olfactory system via the nose. Inhaled particles bind to olfactory receptor cells that are found in the tissue lining the nasal cavity and are then relayed to the olfactory bulb and in turn to the hippocampus. This is the part of the brain responsible for memory and learning.

The connection between the olfactory system and Alzheimer’s is well established, as 85 per cent to 90 per cent of patients experience loss of smell as an early sign of the condition. While it’s not clear what the mechanism is that leads to this symptom, the Colorado scientists hypothesise viral infections could contribute.

Their investigations have led to hope that in future a vaccination could be developed to prevent dementia. As there’s currently no cure for the disease, reducing the risk of getting it by up to 30 per cent through a vaccine could be a big step forward in the battle against dementia.

Photo credit: Unsplash/Mufid Majnun

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