Could a simple vaccine help prevent dementia?

Could a simple vaccination help prevent dementia? This is the question being asked in a recent study published in Nature.

This news comes at a time when we are facing a public health crisis in the US:

• Kennedy’s HHS cancelled the meeting that normally determines what next season’s flu shot will be.

• Another committee that helps set vaccine policy had its usual meeting postponed for months—they are supposedly going to meet this month.

• The decision about whether to approve another version of the covid vaccine has been delayed without explanation.

• Measles continues to spread unchecked, especially in Texas. Clinics in Texas that provide vaccinations are shutting down due to the latest Trump budget cuts.

But back to the good news.

The UK, like most Western European countries, keeps very good health data. It makes it much easier for researchers to ask important questions about the health of the population. For example you could use the data to see if there were a clustering of a rare cancer around a toxic waste dump, or if declining lung cancer diagnoses and quitting smoking are related.

Researchers partly funded by the US NIH (a funding source which has since undergone crippling cuts) took advantage of an interesting phenomenon—in Wales the shingles vaccine (the older version; not the one we currently use) was authorized for adults born after a specific date, and not before. This gave them a ready-made “natural experiment”. They followed these groups of patients over time and counted the number of people diagnosed with dementia over a seven year period. What they found was very interesting: there were significantly fewer dementia diagnoses in the vaccination group.

These results do not show that shingles shots prevent dementia, but they certainly give some interesting hints. There are other studies that have shown a similar trend, but this sort of experiment is not designed to evaluated causation, only association. Shingles vaccination was associated with a lower risk of being diagnosed with dementia, but that association could be due to something else completely, perhaps another factor that they didn’t account for.

Still, this is a very interesting study and one that will hopefully lead to more research. If it turns out that shingles shots give even a little protection against dementia, well, great! We need them after 50 years of age anyway. It’s more incentive for us to get our shots.

If you need incentive, shingles is horrible. Anyone who has had chickenpox is at risk for shingles. Chickenpox and shingles are caused by human herpesvirus 2, better known as varicella zoster virus (VZV). Human herpes viruses are forever, as anyone who’s had a cold sore can attest to. Under the right conditions, the chickenpox virus you caught as a kid can reactivate and cause a very painful rash. The rash lasts a couple of weeks but the pain can last for the rest of your life. Shingles vaccines are excellent at preventing this.

And since 1995, we have regularly vaccinated kids in the US against chickenpox. This means they will never get shingles. Could it also mean that they will be at lower risk of dementia than their parents’ generation? That’s a question we wont be able to answer for a few more decades, when these “kids” are old enough to be diagnosed with dementia.

This is really clever and interesting research, but needs to be studied further to see if there is truly a causal connection here. Given the current leadership’s feelings on vaccinations in general, and the moves they’ve already taken against vaccination in the US, it might be a very long time until we can ask the right questions.

Stay well.

-pal