Adam’s Journal
I got the shingles vaccine a few years ago to – you guessed it – protect me from shingles. Now I hear it might also have beneficial effects when it comes to preventing Alzheimer’s. I am, of course, quite happy about this news, but it seems weird.
Dr. Scofield Prescribes
It does seem weird. Still, a new study adds the strongest evidence yet to a growing body of research that getting the shingles vaccine can cut the risk of developing Alzheimer’s and other forms of dementia.
Shingles is triggered by a form of the herpes virus that causes chicken pox. That virus, varicella-zoster, lurks in our cells following initial childhood infection. Later in life, it resurfaces in the form of shingles, which can bring painful rashes and blisters, as well as nerve pain that can become chronic and disabling.
There has been growing evidence that the herpes virus may have a role in the disease process that leads to dementia. As it turns out, a unique set of circumstances set the stage for a natural experiment to investigate this question.
The first vaccine to prevent shingles, Zostavax, was approved by the US Food and Drug Administration in 2006. But it wasn’t rolled out in Wales until 2013.
In the US, the FDA now recommends that everyone 50 and older be immunized. However, due to tight supply, only those Welsh people who turned 79 beginning in 2013 would be eligible to get a shot. And they’d only be eligible for a single year, as the vaccine was believed less effective in those over 80.
For the next seven years, researchers tracked Welsh people in the two groups: Those who received the vaccine and those who never got the chance. In particular, using statistical weighting, they focused on people who were closest in time to the cutoff – those who turned 80 just before the rollout, and those who narrowly made the cutoff. The scientists also carefully searched for “confounding” variables, hidden factors that could influence the results of the study.
When the scientists completed their analysis, which involved reviewing the health records of 280,000 people, they found that those who’d received the shingles vaccine were 20% less likely to develop dementia over the next seven years than those who weren’t vaccinated.
Theories about why include that the vaccine helps reduce neuroinflammation caused by reactivation of the varicella-zoster virus. Another factor could be that the vaccine helps activate the immune system more generally, which might provide broad protection against dementia.
The study didn’t distinguish among the various types of dementia, but other research has suggested that shingles vaccination is especially protective against Alzheimer’s.
Since the onset of the study, the Zostavax vaccine has been replaced by Shingrix, which has been shown to offer better long-term protection against shingles. A study from last year indicates that Shingrix could also have a leg up on Zostavax when it comes to preventing dementia.
Bottom line: Getting a shingles vaccination was already a no-brainer. So, if you’re 50 or older and haven’t already, here’s one more reason to get it done.
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Dr. Hal Scofield is a physician-scientist at the Oklahoma Medical Research Foundation, and he also serves as Associate Chief of Staff for Research at the Oklahoma City VA Medical Center. Adam Cohen is OMRF’s senior vice president and general counsel. Send your health questions to contact@omrf.org.
