EXPERT REACTION: Shingles vaccine reduces dementia risk by a fifth over seven years (Nature*)
The shingles vaccine reduced the probability of new dementia diagnoses by around one-fifth over seven years, according to a large-scale study from Wales in the UK. In Wales, people born on or after 2 September 1933 were eligible for shingles vaccination, whereas those born before this date were not eligible, allowing researchers to compare two groups of people who differed in age by just a few weeks. When they compared new dementia diagnoses between the vaccine-eligible and ineligible populations, they found that receiving the vaccine decreased the likelihood of being diagnosed with dementia during the seven-year follow-up period by approximately 20%.
Dr Joseph Doyle is a Professor of Infectious Diseases at Monash University and President of the Australasian Society for Infectious Diseases
“The paper [by Eyting and colleagues in Nature] presents results of a natural experiment in Wales, United Kingdom, on the effect of shingles vaccination on new diagnosis of dementia. The study observed that older adults appeared to have less chance of dementia diagnosis in the seven years after receiving live-attenuated shingles vaccination (Zostavax). The authors estimate there were 3.5% fewer dementia diagnoses among people who received the live-attenuated shingles vaccine.
This study had an observational design, so we need to be cautious in assuming the vaccine itself caused this decline in dementia diagnoses. It is plausible that episodes of infection, immune system changes, or health care engagement are among the factors behind this association, but further research is needed to help determine whether there is a causal link.
Importantly, we don’t know whether these findings apply to both the live-attenuated shingles vaccine (Zostavax) used in their study and the newer recombinant subunit shingles vaccine (Shingrix) now used widely in Australia.
Australia approved and subsidised Shingrix on the National Immunization Program in 2023. This newer shingles vaccine is available for older adults and is safer for people who are immunocompromised.
While we do not know whether the newer shingles vaccine used locally has the same association with less dementia yet, we do know the shingles vaccine provided free in Australia is very effective and protective against episodes of shingles.
Older adults and people with weak immune systems at higher risk of shingles are encouraged to see their doctor to talk more about vaccination.”
For more information click here.
Prof Doyle is a board member of the Australian Society for Infectious Diseases and the Pharmaceutical Benefits Advisory Committee. The views expressed here are personal opinions and are not necessarily those of his employers or professional bodies.