Study suggests shingles vaccine may reduce dementia risk

A study published in Nature Medicine has suggested that people who received a newer version of the shingles vaccine, called “Shingrix”, appear to have a lower risk of dementia than people who were given an older shingles vaccine.

Experts have called for more research to better understand the findings.

Shingles is a painful rash that can flare up in people who’ve previously had chickenpox, which is caused by the Herpes zoster virus. It’s more common as people get older – about one in five people who have had chickenpox will develop shingles.

Researchers at the University of Oxford and National Institute of Health and Care Research (NIHR) Oxford Health Biomedical Research Centre (OHBRC), which also funded the study, looked at health records of over 200,000 people in the US. They found that those who had received Shingrix had a 17% reduction in the onset of dementia compared to those who received Zostavax.

“The size and nature of this study makes these findings convincing, and should motivate further research. If validated in clinical trials, these findings could have significant implications for older adults, health services, and public health.” said Dr Maxime Taquet, NIHR Academic Clinical Lecturer in the Department of Psychiatry at Oxford, who led the study.

In 2017, there was a switchover in the US from Zostavax to Shingrix due to Shingrix proving to be a more effective vaccine in preventing shingles. This allowed researchers to analyse the risk of dementia in both people who’d received Shingrix in the six years following the switchover, and those who had received Zostavax previously.

However, experts emphasised that the study only looked back at people’s previous records, rather than following them over time. This means it was unable to prove the vaccine was directly responsible for the reduced dementia risk.

‘’It isn’t clear how the vaccine might be reducing risk, nor whether the vaccine causes a reduction in dementia risk directly or whether there’s another factor at play.” said Dr Sheona Scales, Director of Research at Alzheimer’s Research UK. ‘’So, it will be critical to study this apparent effect further.’’

There was also a limit on the information researchers had on people’s circumstances, including socioeconomic status and health and lifestyle factors. ‘’People should be aware that there are other factors that have definitively been linked to an increased dementia risk. These include things like smoking, high blood pressure and excessive alcohol consumption,’’ said Dr Scales.

Since September 2023, Zostavax has been in a phased withdrawal and replaced with Shingrix in the UK. A free shingles vaccine is available to people who turn 65, people between 70 and 79, and those 50 or older who have a severely weakened immune system, and anyone with questions about receiving the vaccine should speak to their doctor.

• Alzheimer’s Research UK’s Think Brain Health Check-in outlines the steps you can take to protect your brain health and lower your risk of dementia. Complete the check-in today.