A UK study, published in Nature Medicine, suggests Shingrix, a relatively new vaccine given to protect older adults against shingles, is a better protection at delaying the onset of dementia, than the previous shingles vaccine, Zostavax, which also helped prevent the illness.
The study led by Maxime Taquet and Paul J Harrison, of the Oxford Health NHS Foundation Trust and the Department of Psychiatry, University of Oxford; Quentin Dercon, University College London Institute of Mental Health; and Paul A Todd, Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, found Shingrix delayed dementia onset by 17% compared with Zostavax.
Shingrix has been developed via newer vaccine technology, and is thought to offer stronger and longer-lasting protection. Given in two doses, it is now the preferred option for shingles vaccination in Australia.
In November 2023, Shingrix replaced Zostavax on the National Immunisation Program, making it available for free to those at highest risk of complications from shingles. This includes all adults aged 65 and over, First Nations people aged 50 and older, and younger adults with certain medical conditions that affect their immune systems.
What the study found
By analysing data from electronic health records, they found people who received Shingrix had a 17% increase in “diagnosis-free time” during the follow-up period (up to six years after vaccination) compared with those who received Zostavax. This was equivalent to an average of 164 extra days without a dementia diagnosis.
The researchers also compared the shingles vaccines to other vaccines: influenza, and a combined vaccine for tetanus, diphtheria and pertussis. Shingrix and Zostavax performed around 14–27% better in lowering the risk of a dementia diagnosis, with Shingrix associated with a greater improvement.
The benefits of Shingrix in terms of dementia risk were significant for both sexes, but more pronounced for women, which is not entirely surprising. Women have a higher risk of developing dementia due to interplay of biological factors. These include being more sensitive to certain genetic mutations associated with dementia and hormonal differences.