Everyday Viruses Could Be Priming Our Brain for Neurodegeneration Over Time

It's a slow-burn effect.

Image adapted from rawpixel.com

What if I told you that neurodegenerative diseases originate not from a single catastrophic event, but from a lifetime of seemingly trivial infections? New evidence from the U.S. National Institutes of Health (NIH) suggests that it’s the everyday viruses — the kind most of us catch and forget — that are silently reprogramming neurons in ways that mirror patterns seen in the brains of those with Alzheimer’s disease (AD).

New Evidence

The new evidence I’m referring to is a preprint from the NIH, specifically from the National Institute on Aging and the National Institute of Neurological Disorders and Stroke. It was released in March 2025, titled “Proteomic Analysis of Endemic Viral Infections in Neurons Offers Insights into Neurodegenerative Diseases.” While preprints have not yet undergone peer review, they publicize early evidence on crucial topics. Plus, the preprint authors, Li et al., have an impressive track record of quality publications.

What Li et al. did was straightforward yet ingenious. They grew human neurons in the laboratory and repeatedly exposed them to five common viruses at low loads over time (days 1, 2, and 5). These viruses are the ones most of us encounter in our lifetime:

• Herpes simplex virus 1 (HSV-1), known for causing oral sores.

• Human coronavirus 229E (HCoV-229E), a common cold virus.

• Epstein-Barr virus (EBV), the cause of mononucleosis (a type of fever).

• Varicella-zoster virus (VZV), the cause of chickenpox and shingles.

• Influenza A virus (H1N1), a seasonal flu virus.

Li et al. then tracked how the neurons responded over time using a powerful technique called mass spectrometry-based proteomics, which enabled them to detect and measure the levels of thousands of proteins within each neuron. Essentially, Li et al. measured how infections affect the neuron’s proteome, i.e., what proteins the cell is producing and expressing.

Following virus exposure, Li et al. observed a clear increase in the amount of viral proteins inside the neurons, confirming that the viruses had successfully infected the neurons. Each virus also left behind a unique set of protein fragments, making it easy to tell which virus infected the neurons.

What they found next was striking.

Viruses Reshape Protein Networks in Neurons