Shingles is awful, but here's another reason to get vaccinated: It may
fight dementia
[April 03, 2025]
By LAURAN NEERGAARD
WASHINGTON (AP) — A vaccine to fight dementia? It turns out there may
already be one – shots that prevent painful shingles also appear to
protect aging brains.
A new study found shingles vaccination cut older adults’ risk of
developing dementia over the next seven years by 20%.
The research, published Wednesday in the journal Nature, is part of
growing understanding about how many factors influence brain health as
we age – and what we can do about it.
“It’s a very robust finding,” said lead researcher Dr. Pascal Geldsetzer
of Stanford University. And “women seem to benefit more,” important as
they’re at higher risk of dementia.
The study tracked people in Wales who were around 80 when receiving the
world’s first-generation shingles vaccine over a decade ago. Now,
Americans 50 and older are urged to get a newer vaccine that's proven
more effective against shingles than its predecessor.
The new findings add another reason for people to consider rolling up
their sleeves, said Dr. Maria Nagel of the University of Colorado
Anschutz Medical Campus, who studies viruses that infiltrate the nervous
system.
The virus “is a risk for dementia and now we have an intervention that
can decrease the risk,” Nagel said.
With Alzheimer’s and other forms of dementia on the rise in an aging
population, “the implications of the study are profound,” Dr. Anupam
Jena, a Harvard physician and health economist, wrote in a Nature
commentary.
What is shingles?
Anyone who’s had ever had chickenpox – nearly everybody born before 1980
– harbors that virus for the rest of their life. It hides in nerves and
can break out when the immune system weakens from illness or age,
causing painful, blister-like sores typically on one side of the body
that last for weeks – what’s called shingles.
About 1 in 3 Americans will get shingles, according to the Centers for
Disease Control and Prevention. While most recover, it sometimes causes
severe complications. If it infects an eye it can cause vision loss. Up
to 20% of shingles patients suffer excruciating nerve pain months or
even years after the rash itself is gone.
What’s the link between shingles and dementia?
It’s not clear exactly how Alzheimer’s and other types of dementia form.
But certain viruses that sneak inside the nervous system – especially
members of the herpes family including the chickenpox virus -- have long
been suspected of adding to genetic and other factors that make people
more vulnerable.
Last summer, doctors at Boston’s Brigham and Women’s Hospital reported
that an episode of shingles could raise someone’s risk of dementia by
about 20%.
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Partly, it’s because that virus can cause inflammation, bad for organs
including the brain. It also can directly infect blood vessels in the
brain, causing clots and impeding blood flow, said Colorado’s Nagel, a
risk both for strokes and for dementia.
More intriguing, her lab also discovered shingles can spur formation of
a sticky protein called amyloid that’s one of the hallmarks of
Alzheimer’s.
Do shingles vaccines protect against dementia?
Adults who get recommended vaccines tend to have other brain-healthy
habits including exercising and a good diet, which made it hard to prove
an extra benefit.
Stanford’s Geldsetzer took advantage of “a natural experiment” in Wales,
which opened shingles vaccinations with an age limit: anyone 80 or older
on Sept. 1, 2013, was ineligible but those still 79 could squeeze in.
Comparing seniors who just met or just missed that cutoff would mimic a
research study that randomly assigned otherwise similar people to be
vaccinated or not.
Geldsetzer’s team analyzed more than 280,000 medical records and found
evidence that vaccination did offer some protection against dementia. At
the time, people received a first-generation vaccine called Zostavax.
An important next step is testing whether today’s vaccine, Shingrix,
also offers dementia protection, Nagel said. Another research group
recently reported some evidence that it does. Vaccine manufacturer GSK
last month announced a collaboration with UK health officials to track
seniors’ cognitive health as they get vaccinated.
Geldsetzer also hopes to further study that earlier shot to see if the
type of vaccine might make a difference.
What are the shingles vaccine recommendations?
Shingrix is a onetime vaccination, given in two doses a few months
apart. The CDC recommends it starting at age 50 for most people but also
for younger adults with certain immune-weakening conditions – including
those who years ago got that first-generation shingles vaccine. Fewer
than 40% of eligible Americans have gotten vaccinated.
Side effects including injection-site pain and flu-like fever and
achiness are common. The CDC cautions if you’re currently fighting
another virus such as the flu or COVID-19, to wait on a shingles shot
until you’re well.
While there’s no proven prevention for dementia, doctors also recommend
other commonsense steps to lower the risk. Stay socially and cognitively
active. And control high blood pressure and, for people with diabetes,
high blood sugar, both of which are linked to cognitive decline.
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