Can the shingles vaccine really lower dementia risk?

Shingles is infamous for causing a painful, blistering rash in older adults. But new research suggests its vaccine might also do something extraordinary: protect your brain. A recent study in Nature found that seniors who received the shingles vaccine were about 20% less likely to develop dementia than those who didn’t​. This surprising link, highlighted by National Geographic, adds to growing evidence that preventing infections like shingles could have spillover benefits for our long-term memory and cognition.

A Natural Experiment in Wales

Why are scientists so excited about this particular study? It boils down to how it was done. In Wales, a quirk in public health policy created a perfect “natural experiment.” Starting in 2013, only people born on or after September 2, 1933 were eligible to get a shingles vaccine (the older live vaccine, Zostavax) around their 80th birthday – those born just a day earlier missed out​. This odd cutoff split older folks into two similar groups: one that could get vaccinated and one that couldn’t, purely based on birthdate. That setup allowed researchers to compare dementia rates with much less bias than usual (after all, your birthday is random – it doesn’t also affect your dementia risk). The result? Dementia diagnoses dropped by about 20% over the next seven years in the group who got the shingles shot. In other words, the vaccinated group had a significantly lower chance of developing dementia than their unvaccinated peers. That’s a big deal, considering how tough it’s been to find anything that lowers dementia risk in older adults.

(For context, earlier studies had hinted vaccines might protect the brain, but it was hard to be sure since people who choose to get vaccinated tend to be healthier to begin with​. The Wales “birthdate experiment” elegantly avoided that problem.)

Old vs. New: Shingrix Outshines Zostavax

Interestingly, the Wales study largely involved Zostavax, the older shingles vaccine. But since 2017, Zostavax has been replaced in the U.S. and UK by a newer vaccine called Shingrix. So, do people getting Shingrix see a similar brain benefit? A 2024 study in Nature Medicine set out to answer that by taking advantage of another natural experiment – the abrupt switch from Zostavax to Shingrix. In late 2017, clinics stopped using Zostavax and started using Shingrix almost overnight, so whether an older adult got the live vaccine or the new one was basically luck of timing​. The Nature Medicine study found that Shingrix was associated with an even lower dementia risk than Zostavax. In fact, those who received Shingrix had about a 17% lower risk of developing dementia compared to those who had gotten the old vaccine​. Put another way, the newer shingles shot gave people more dementia-free time (on average adding a few extra months before any dementia might appear).

Researchers even noted Shingrix recipients fared better than folks who got other common vaccines like flu or tetanus boosters, hinting that the shingles-specific effect was real​. Both the Welsh study and the vaccine-swap study point to the same conclusion: protecting yourself from shingles may also protect your mind.

Shingles 101: A Rash and a Remedy

What exactly is shingles, and why do we vaccinate for it in the first place? Shingles (medical name: herpes zoster) is caused by the varicella-zoster virus – the same virus that gives you chickenpox. After you recover from chickenpox, this crafty virus goes into hiding in your nerve cells. Decades later, if your immunity wanes, the virus can wake up and erupt as shingles, causing a distinctive band of painful blisters on the skin​. Besides the misery of the rash itself, shingles can lead to lingering nerve pain that lasts for months or years (a complication called postherpetic neuralgia). In rare cases, the virus can even affect the brain or eyes seriously. In short, shingles is not something you want to experience if you can help it.

Thankfully, we have vaccines. Shingrix, approved in 2017, is a two-dose vaccine that is over 90% effective at preventing shingles and its complications in older adults​. It’s so effective that it basically made Zostavax (an older, less potent live vaccine) obsolete. The CDC recommends Shingrix for all adults 50 and up, and for certain younger adults with weakened immune systems. (There’s no upper age limit – even if you’re 80+, it’s still recommended, and even if you’ve had shingles or the old vaccine before, you should get Shingrix.​) The public health reason is straightforward: to prevent the agony of shingles. But now, if these dementia findings hold up, getting this shot might serve double duty.

How Could a Shingles Shot Protect the Brain?

At first blush, it sounds odd that a vaccine for a skin rash might also fend off dementia. Scientists are still unraveling the why, but a couple of plausible theories have emerged:

• Keeping the Virus in Check: The shingles vaccine prevents the varicella-zoster virus from reactivating in your body. That’s important because when this virus does flare up (even mildly, sometimes without a full rash), it can trigger inflammation throughout the nervous system. Some studies suggest these viral reactivations might contribute to neuroinflammation, which is a known factor in cognitive decline and Alzheimer’s disease​. By stopping those silent smoldering infections, the vaccine could indirectly reduce one source of brain inflammation.

• Immune Bootcamp: Vaccines don’t just target a specific germ; they also act as a general training session for your immune system. Especially with live-attenuated vaccines like Zostavax, researchers think there can be off-target effects where the immune system gets extra revved up or “tuned” in a helpful way​. This phenomenon, sometimes called trained immunity, might help your body better fend off other infections or even clear out toxic proteins linked to dementia​. In the Wales study, for example, vaccinated folks even had fewer hospitalizations for other infections, hinting at a broader immune boost beyond just preventing shingles. A more vigilant immune system could mean less wear-and-tear on the brain over time.

  To be clear, these mechanisms are still theories. Dementia is a complex, multifactorial disease, and the idea that a vaccine could reduce risk by 20% is both exciting and surprising. It will take further research (including clinical trials) to confirm cause-and-effect and to see if the benefits extend to the new recombinant vaccine in the long run. Scientists also want to understand why some effects appeared stronger in women than men in these studies​ – could hormonal or genetic differences play a role in how vaccines influence the brain? There’s a lot to dig into.

A Shot Worth Considering

There is currently no cure for dementia, and even the newest treatments can only modestly slow it down. That’s why a simple vaccine showing promise in preventing dementia has experts cautiously optimistic. If getting a shingles shot in your 50s or 60s could lower your risk of memory loss years later, it would be a huge win for public health – a cheap, safe, one-time (well, two-time) intervention to help protect our aging brains. As one neurologist put it, this would be “much more effective than any other pharmacological tools out there for dementia” if the effect is truly causal​

We’re not quite ready to declare the shingles vaccine a guaranteed brain-saver. But considering it already protects you from a pretty horrible illness, the potential bonus of preserving your mind makes it even more of a no-brainer (pun intended). In the end, rolling up your sleeve for that shingles shot might pay off with more than just a shingles-free life – it could help.

Do you know how much salt is too much? and that vitamin A and E supplements can hurt you? Also, heck out this in-depth view about storing your medical records in CA. Do you know who owns healthcare records in CA? and find out the benefits of health records for patients.