Did you have chickenpox as a kid?

If the answer is yes (which it is for most of us), you’re at risk of getting shingles. Shingles is caused by the varicella-zoster virus, the same virus that causes chickenpox. After one recovers from chickenpox, the virus remains dormant in one’s nerve cells. Later in life, if the virus reactivates (which depends on factors like age, stress, or a weakened immune system), it can cause shingles. A bout of shingles is pretty miserable, which is reason enough to consider getting a herpes zoster vaccine to prevent its occurrence.

The vaccine does more than you think.

But guess what! The shingles vaccine protects you against more than just shingles. In fact, mounting evidence has demonstrated that getting a shingles jab reduces your likelihood of developing dementia.

In 2025, Welsh researchers compared a group of older people who received live-attenuated herpes zoster vaccine (Zostavax) to another group who didn’t get jabbed. The scientists followed the patients for an average of seven years. Over the course of the study, those who got the vax were twenty percent less likely to develop dementia.

What about Shingrix?

Zostavax, though, is being replaced with a newer vaccine called Shingrix, which is based in recombinant DNA technology. So, does Shingrix also prevent dementia? It turns out that it does. What’s more, it may be even better than Zostavax. In 2024, a group of British scientists compared separate cohorts who received one or the other of the two vaccines during a six-year-long study. The researchers reported that the group who were jabbed with Shingrix had a seventeen percent lower risk of being diagnosed with dementia when compared to the people who got Zostavax. Applying some statistical hocus pocus to the data, the researchers lauded one hundred and sixty-four extra dementia-free days for those who later developed dementia.

Evidence in favor of shingles vax was bolstered by another 2024 report. A multinational group of scientists systematically reviewed and meta-analyzed five studies (including cohort, case-control, and cross-sectional designs) covering a total of 103,615 zoster-vaccinated individuals. The review demonstrated a consistent association between herpes zoster vaccination and a reduced dementia risk.

How might the vaccine reduce dementia risk?

Scientists still aren’t sure how the shingles vaccine may reduce dementia. They do have a few theories though:

• Reduction of viral reactivation: The shingles vax prevents reactivation of the varicella-zoster virus (VZV), which causes chickenpox and shingles. VZV can remain dormant in nerve cells and, when reactivated, may cause inflammation or damage in the nervous system. This inflammation or direct infection of brain blood vessels can contribute to cognitive decline, potentially leading to dementia. By preventing shingles, the vaccine may reduce this risk.
• Immune system modulation: The shingles jab, particularly the recombinant Shingrix, contains adjuvants that boost the immune response. This enhanced immune activity might protect the brain by reducing chronic inflammation or clearing harmful proteins, like amyloid, associated with Alzheimer’s disease.
• Prevention of amyloid formation: In 2020, a group of researchers from Colorado reported that VZV reactivation can spur the formation of amyloid proteins, a hallmark of Alzheimer’s disease. By preventing shingles, the jab may limit this process, reducing dementia risk.

Bottom line

So, if you’re on the fence regarding whether or not to get vaxxed against shingles, here’s a little shove!

Marc Arginteanu is a neurosurgeon and author of Azazel’s Public House.