New Shingles Vaccine May Cut Risk of Dementia

A new study suggests that the new, more effective recombinant shingles vaccine can also reduce the risk of dementia, similar to the vaccine’s discontinued predecessor.

The study is published in Nature Medicine.

Links to dementia risk

Shingles is caused by a reactivation of the chickenpox-causing herpes zoster virus. After first infection, commonly during our childhood years, the virus is never fully eradicated, and it lies dormant in our nervous system.

The virus can flare up again to cause shingles, a painful and serious condition that affects many elderly people. Interestingly, evidence emerged after the introduction of the shingles vaccine suggesting that it may reduce the risk of dementia.

This vaccine – Zostavax® – has now been withdrawn in many countries in favor of a more effective recombinant vaccine – Shingrix®. However, it was unclear whether the newer vaccine had a similar effect on dementia risk.

Delaying dementia onset?

To find out if this was the case, University of Oxford researchers studied the electronic records of over 200,000 people aged over 65 in the US. They looked at over 100,000 people who received the previous vaccine from 2014–2017 and the same number who received the recombinant vaccine from 2017–2022.

The participants were followed up for four to six years after vaccination to determine how many were diagnosed with dementia.

The findings revealed that there was indeed a lower risk of dementia among those who received the recombinant vaccine in the 6 years post vaccination, with a 17% delay in the onset of dementia. This translates to an extra 164 days lived without the disease compared to those who received Zostavax.

“There was already some evidence that the old live vaccine was able to reduce the risk of Alzheimer’s disease,” said Prof. Andrew Doig, professor of biochemistry at the University of Manchester. “This work shows that the new recombinant vaccine is even more effective, decreasing the likelihood of being diagnosed with dementia, if the new vaccine is used rather than the old one.”

The recombinant shingles vaccine was also linked to lower dementia risks when compared against other vaccines routinely given to older people, including influenza and tetanus/diptheria/pertussis vaccines.

Additionally, the effect on dementia risk was observed for both men and women but was greater in women.

Further research needed

“The study is very well-conducted and adds to previous data indicating that vaccination against shingles is associated with lower dementia risk. More research is needed in future to determine why this vaccine is associated with lower dementia risk,” said Prof. Tara Spires-Jones, director of the Centre for Discovery Brain Sciences at the University of Edinburgh.

Findings should stimulate further studies to probe the mechanism behind this association, such as large-scale randomized control trials.

“The next question is, how does vaccination exert this dementia protection effect?” said Prof. Robert Howard, professor of old age psychiatry at University College London. “Is it through suppression of virus or is the induced immune response targeting a step in the molecular pathology of Alzheimer’s disease?”

Reference: Taquet M, Dercon Q, Todd JA, Harrison PJ. The recombinant shingles vaccine is associated with lower risk of dementia. Nat Med. 2024:1-1. doi: 10.1038/s41591-024-03201-5