Study Shows that Shingles Vaccine Protects Against Dementia

A new study provides even more motivation to get that shingles vaccine when eligible: for reasons scientists don’t fully understand, getting vaccinated helps prevent dementia.

This discovery adds to evidence that has cropped up in recent years pointing to potential viral causes for some of the neurological disorders that have long seemed to strike at random. A few years ago, the scientific community was abuzz with excitement when a massive long-term study finally established a clear link between being infected with Epstein-Barr virus and developing multiple sclerosis. The association had been suspected before that, but the ability to mine data from 10 million people serving in the U.S. military turned up the information needed to make it stick.

In this new study showing protection against dementia from the shingles vaccine, it certainly looks like the virus that causes shingles might also somehow cause dementia. (A quick refresher on shingles: initial infection with the varicella-zoster virus typically causes chickenpox. Later in life, the long-dormant virus can be reactivated, this time manifesting as shingles.) The reality of the correlation between vaccine and virus could be more complicated, and will probably take several years for scientists to untangle. While it’s possible that the reactivation of this virus somehow leads to dementia, it could also be the case that the massive immune response caused by the reactivation is itself the trigger — or even some completely different mechanism than either of these.

Here’s what we do know, thanks to the team of scientists at Stanford. They took advantage of a unique situation that made it possible to let nature run a massive experiment for them: in Wales, eligibility for the shingles vaccine was pinpointed to a specific date of birth. Anyone born prior to September 2, 1933, could not get the vaccine, and anyone born that date or later could get it. By studying electronic health records, the scientists were able to compare groups of people born shortly before and shortly after that cutoff date, reviewing follow-up data collected for each person as much as seven years after vaccination.

What they found was remarkable: a 20% relative reduction in dementia for people who got the vaccine compared to those who didn’t. Interestingly, the protective effect was stronger in women, who are more likely to develop dementia than men. And since scientists like to double-check their work, they took this new theory out for a spin in a different population. By reviewing death certificates for people in England and Wales, they confirmed the initial findings: more vaccine use, less dementia.

The shingles vaccine isn’t right for everyone, so please don’t rush out and get it in an attempt to ward off dementia. But if you are eligible and the vaccine is appropriate for you, this study may provide a little extra motivation to get the jab.