The Shingles vaccine does more than protect you from shingles
Vaccines have gotten a lot of press lately. Did you know there's evidence the Shingles one can also help prevent dementia?
If you've ever had chickenpox (varicella) you've probably also heard of shingles (herpes zoster).
They're called different things, but they're caused by the same virus!
Varicella zoster (VZV) is the herpesvirus that's responsible for both and because it's a herpesvirus, it has a latent phase and hides within you to reactivate when you least expect it.
This generally happens in old(er) age and shingles is typified by a very painful and blistery skin rash (many times afflicting the face or neck).
VZV is legendary for its ability to torment both the young and old and it's able to do this because after initial infection in early childhood (which includes 95% of us!) it goes dormant in our nerves.
Approximately HALF of individuals who live to the age of 85 will experience at least one bout of reactivation.
Fortunately, there's been a vaccine for shingles since 2006, Zostavax (weakened live virus), which was replaced by a recombinant vaccine, Shingrix (against glycoprotein E), in October of 2017 in the United States.
The recombinant vaccine provides up to 90% protection against reactivation of VZV and also reduces the risk of unintended infections that can occur from the use of a live virus vaccine.
But, vaccination against VZV has other benefits, and studies with Zostavax have shown that the live virus vaccine also reduces the incidence of dementia in women (but not men).
This isn't all that surprising since herpes viruses have been shown to be associated with dementia, and it makes sense that prevention of their reactivation could potentially reduce its development.
However, the mechanism of the dementia reducing powers of Zostavax are unknown, and since the US made a rapid transition from the live virus vaccine to the recombinant vaccine, it wasn't known whether it also reduced the development of dementia.
Based on the results presented in the figure above, we now have a pretty good idea that it does.
The authors of this paper looked at the development of dementia in a group (cohort) of 103,837 people and saw that there was a) a rapid transition to Shingrix in October 2017 b) the rates of dementia were reduced (17%) in this group of individuals after that date d) the recombinant vaccine performs better than the live vaccine e,f) the vaccine prevented dementia in both sexes, although the effect was much more pronounced in females.
The authors went on to show that people vaccinated against other viruses (influenza and tetanus, diphtheria, and pertussis (tdap)) didn't have the same reduction in the development of dementia indicating that there's something special about VZV vaccination.
While the results of this study are promising, it’s important to keep in mind that this is an ‘observational’ study which means it could be subject to certain biases in how the group of patients were selected for further review.
To truly understand if the shingles vaccine provides protection from the development of dementia will require a full clinical trial.
But, dementia prevention would just be a cherry on top of the already proven benefits of shingles vaccination.
Brian Krueger