Shingles vaccine can decrease risk of dementia, study finds

Getting vaccinated against shingles can reduce the risk of developing dementia, a large new study has found.

- Pam Belluck

LONDON -

The results provide some of the strongest evidence yet that some viral infections can have effects on brain function years later and that preventing them can help stave off cognitive decline.

The study, published on April 2 in the journal Nature, found that people who had received the shingles vaccine were 20 per cent less likely to develop dementia in the seven years afterwards than those who had not been vaccinated.

"If you're reducing the risk of dementia by 20 per cent, that's quite important in a public health context, given that we don't really have much else at the moment that slows down the onset of dementia," said Dr Paul Harrison, a professor of psychiatry at the University of Oxford. Dr Harrison was not involved in the new study but has done other research indicating that shingles vaccines lower dementia risk.

Whether the protection can last beyond seven years can be determined only with further research.

But with few currently effective treatments or preventions, Dr Harrison said, shingles vaccines appear to have "some of the strongest potential protective effects against dementia that we know of that are potentially usable in practice".

Shingles cases stem from the virus that causes childhood chickenpox, varicella-zoster, which typically remains dormant in nerve cells for decades.

As people age and their immune systems weaken, the virus can reactivate and cause shingles, with symptoms such as burning, tingling, painful blisters and numbness.

The nerve pain can become chronic and disabling.

In the United States, about one in three people develops at least one case of shingles, also called herpes zoster, in his or her lifetime, the Centres for Disease Control and Prevention (CDC) estimates.

About a third of eligible adults have received the vaccine in recent years, according to the CDC.