The shingles vaccine, typically administered to fend off a painful rash, might pack an unexpected benefit by delaying or even preventing dementia.

Groundbreaking research from Stanford University, focusing on the UK population, indicates that the jab could ward off dementia more effectively than existing treatments.

Published in the prestigious Nature journal, the researchers capitalised on the “unique way” Wales introduced the vaccine to understand its impact on dementia across different age groups.

The vaccine was made available for at least a year in 2013 specifically for those born between September 1933 and September 1934. People born even just days before this weren’t eligible for the vaccine while those born in October 1934 had to wait an extra year to get their vaccine.

Because of this precise targeting based on birth dates, scientists were able to directly compare results between people in similar age groups and found a 3.5% decrease in dementia risk over the following seven years post-vaccination.

This figure signifies an approximate 20% lowered dementia likelihood overall. Notably, the protection was more pronounced in women.

Looking to England’s rollout of the same vaccine reinforced these findings, with a second analytical method further validating the results.

Scientists have long believed there was a link between shingles and dementia, but the overwhelming evidence from a recent study has led experts to suspect there’s more to the story.

Researchers are now intrigued by the possibility that vaccines may boost the immune system’s response to the point where it fights other things aside from the intended virus, such as neuroinflammation and infections linked to dementia.

Researchers have weighed in: “Our substantial effect sizes, combined with the relatively low cost of the zoster vaccine, imply that, if these findings are truly causal, the zoster vaccine will be both far more effective as well as cost-effective in preventing or delaying dementia than existing pharmaceutical interventions.”

They underscored the importance of more studies looking at why the shingles vaccine impacts dementia risk.

Despite their insights, the researchers acknowledged drawbacks in their study: “Our study has several limitations.”

Missed and delayed dementia diagnoses were taken into account before releasing the results, meaning the reported 20% reduction in risk is a “conservative” figure.

Focusing on individuals born between 1933 and 1934 also restricted the study, leaving questions about whether the findings apply to younger cohorts.

Researchers added: “We were limited to a maximum follow-up period of 8 years. Our study can therefore not inform on the effectiveness of the zoster vaccine for reducing dementia occurrence beyond this time period.”

Moreover, since the study was conducted, a different shingles vaccine has been introduced in the UK in 2023.

The research focused on the live-attenuated zoster vaccine Zostavax, but the one currently in use is the recombinant subunit zoster vaccine, known as the Shingrix vaccine.