Shingles and RSV Vaccines Show Promise Against Dementia

New study findings published by investigators in Nature found that 2 AS01-adjuvanted vaccines—Arexvy (RSVPreF3; GSK), the respiratory syncytial virus (RSV) vaccine, and Shingrix (Zoster vaccine recombinant; GSK), the recombinant shingles vaccine—were linked to a lower dementia risk. The evidence demonstrated that both the AS01-adjuvanted shingles and RSV vaccines related to a reduced 18-month risk of dementia when used individually or combined.^1,2

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"We wanted to investigate why Shingrix appears more effective than Zostavax in reducing the incidence of dementia. One possibility is that Shingrix contains the AS01 adjuvant, whereas Zostavax does not," Paul Harrison, BMBCh, DM, of the University of Oxford in England, said in a news release. "We therefore looked at the risk of dementia following the Arexvy RSV vaccine, which contains the same adjuvant, and found that it had the same effect on dementia risk as Shingrix," Harrison continued. "While this finding does not prove that the adjuvant is important, it supports the possibility."²

AS01 Vaccines and Dementia

Previous studies suggest a link between the shingles vaccine and a reduced risk of dementia, with some studies indicating a stronger effect in women. A recent study of over 100,000 individuals found that Shingrix related to a lower risk of dementia compared with the older Zostavax (Merck) vaccine in men and women—which is now discontinued. The protective impact of Shingrix could be a direct effect of the AS01 adjuvant against dementia, which was previously supported in animal studies. To further assess whether the AS01 adjuvant contributes to this reduced dementia risk, researchers are examining the impact of Arexvy, another AS01-containing vaccine, on dementia risk, comparing its effects against Shingrix and the flu vaccine.¹

In the study, researchers effectively matched 3 groups of individuals to an equal number of individuals who received only the flu vaccine. The groups were divided into those who received only the AS01 RSV vaccine (35,938), those who received only the AS01 shingles vaccine (103,798), and individuals who received both AS01 vaccines (78,658). The matching ensured that all groups were comparable, with very small differences in their characteristics.¹

Study Results

Researchers compared those who received the flu vaccine with the AS01 vaccines and found that those who received the RSV or shingles vaccine were at a lower risk of being diagnosed with dementia, with a restricted mean time lost (RMTL) ratio of 0.71 (95% CI 0.61-0.83) over 18 months. Specifically, the RSV vaccine was associated with a 29% increase in time spent dementia-free, the shingles vaccine with an 18% increase, and receiving both vaccines resulted in an even greater 37% increase in dementia-free time. This translates to an additional 87, 53, and 113 days, respectively, without a dementia diagnosis for those diagnosed within 18 months of vaccination.^1,2

However, the study authors noted that there was not a significant difference in dementia risk between receiving just 1 of the AS01-containing vaccines and receiving both. The findings also held true for both males and females, indicating that sex did not influence the vaccine’s protective effect. These positive findings were consistent even when accounting for individuals who developed dementia early in the follow-up period and when considering a combined outcome of dementia or death.^1,2

The findings suggest that the existing evidence, confirmed by recent studies, demonstrates that both the AS01 shingles and RSV vaccines may protect against dementia. The study authors noted that this protection could stem from the AS01 adjuvant’s specific immunological actions and not just the vaccines’ ability to prevent the targeted infection. However, further research is needed to confirm the results.¹

REFERENCES

1. Taquet, M., Todd, J.A. & Harrison, P.J. Lower risk of dementia with AS01-adjuvanted vaccination against shingles and respiratory syncytial virus infections. npj Vaccines 10, 130 (2025). https://doi.org/10.1038/s41541-025-01172-3

2. RSV Vaccine Tied to Lower Dementia Risk. MedPgaeToday. News release. June 26, 2025. Accessed July 2, 2025. https://www.medpagetoday.com/neurology/dementia/116274?xid=nl_mpt_morningbreak2025-06-27&mh=6d2b5f4f91352444bdf817a9c17750bc&zdee=gAAAAABm4uL9FCoIf1N83nrcwYYqnQUvN6Iw4dbaY-dGva4sOp57nSM2Ew3wD87ohRuoseQBDbCp1MG30J6ETpHXK1wNpp0NgnGTMFXrtFaNfWUoL5ekf-Y%3D&utm_source=Sailthru&utm_medium=email&utm_campaign=MorningBreak_062725&utm_term=NL_Gen_Int_Daily_News_Update_active