Last updated: August 27, 2026
[Key Takeaways]
- A Brown University study of adults age 66 and older recently admitted to a skilled-nursing facility (about 510,000 people) found that dementia diagnoses within four years occurred in 18.8% of those who received the shingles vaccine, compared with 24.6% of those who did not.
- A separate study of roughly 1.5 million Medicare beneficiaries linked shingles vaccination to a 33% lower risk of a new dementia diagnosis in adults 65 and older.
- Multiple outlets, including U.S. News, AARP, and NewYork-Presbyterian's Health Matters, reported on these findings again in August 2026.
- Both studies are observational, so they show an association rather than a proven cause-and-effect relationship.
- Whether to get the shingles vaccine should be based on current CDC guidance and a conversation with your healthcare provider.
It is written in the hope that it can be of even a little help to many readers.
Overview
New research has renewed interest in a possible connection between the shingles vaccine and dementia risk in older adults. Two separate studies — one from Brown University and another based on Medicare claims data — found that adults who received the shingles vaccine were diagnosed with dementia less often than adults who did not. This article summarizes what these studies found, reviews current CDC vaccination guidance, and explains why an association observed in health records is not the same as proof that the vaccine lowers dementia risk. These are observational findings, not a confirmed cause-and-effect relationship, and any vaccination decision should be made in consultation with a healthcare provider.
Table of Contents
What the Research Shows: Shingles Vaccine and Dementia Risk
Interest in a link between the shingles vaccine and dementia risk has grown as several independent research teams have examined the question using different data sources. Two studies in particular have drawn attention in 2026: an analysis from Brown University and a large-scale review of Medicare claims data. Both point in the same general direction, though neither was designed to prove a direct cause-and-effect relationship.
Brown University Study: Dementia Diagnoses Over 4 Years
A team at Brown University reviewed health records for approximately 510,000 adults age 66 and older who had recently been admitted to a skilled-nursing facility for short- or long-term care, comparing rates of new dementia diagnoses between those who received the shingles vaccine and those who did not. The findings were published in June 2026 and drew renewed attention after ScienceDaily republished coverage of the study on 08/23/2026.[1] Among this skilled-nursing-facility population, vaccinated adults were diagnosed with dementia at a rate of 18.8% during the four-year follow-up period, compared with 24.6% among adults who were not vaccinated.[1] Because this study focused on adults in skilled-nursing care — a population that may differ from older adults overall in health status and access to care — its findings may not generalize to all older adults.[1]
[1] Hayes et al., Annals of Internal Medicine (2026)
Because this analysis reviewed existing health records rather than randomly assigning participants to receive the vaccine or a placebo, it is considered observational. That design can identify a statistical pattern, but it cannot, on its own, establish that the vaccine caused the lower dementia rate.
Medicare Study: 33% Lower Dementia Risk in Adults 65+
A separate study analyzed insurance claims data from approximately 1.5 million Medicare beneficiaries to evaluate the relationship between shingles vaccination and dementia diagnoses among older adults.[1] Among adults 65 and older, shingles vaccination was associated with a 33% lower risk of receiving a new dementia diagnosis.[1] This result echoes the pattern seen in the Brown University analysis, even though the two studies drew on different populations and methods.[1]
[1] dos Reis et al., Alzheimer's & Dementia (2026)
News organizations continued to cover these findings in August 2026, including U.S. News & World Report, AARP, and NewYork-Presbyterian's Health Matters.
Why Might the Shingles Vaccine Lower Dementia Risk?
Researchers who study this connection have proposed several possible explanations, though none has been confirmed. One hypothesis under investigation is that the shingles vaccine may reduce reactivation of the varicella-zoster virus, the virus that also causes chickenpox and shingles, which some researchers suspect may contribute to neuroinflammation that has separately been linked to cognitive decline.[1]
[1] Polisky et al., Nature Medicine (2025)
Other researchers have proposed that the vaccine's broader effect on the immune system, rather than the virus itself, could play a role. These proposed mechanisms remain hypotheses under investigation, and researchers have not established a confirmed biological pathway linking the shingles vaccine to reduced dementia risk. Until that underlying mechanism is better understood, the reason behind the observed association remains an open scientific question.
Who Should Consider the Shingles Vaccine?
The shingles vaccine, sold under the brand name Shingrix, was developed and approved to prevent shingles (herpes zoster) and its complications, such as long-lasting nerve pain known as postherpetic neuralgia.[1] Reducing dementia risk is not an approved use of the vaccine, and it should not be viewed as a substitute for other dementia prevention or management strategies discussed with a healthcare provider.
[1] CDC, "Shingles Vaccination"
CDC Guidance for Adults 50 and Older
The Centers for Disease Control and Prevention recommends Shingrix for adults age 50 and older, as well as for adults 19 and older who have weakened immune systems due to disease or therapy.[1] The vaccine is typically given as two doses, spaced two to six months apart.[1]
[1] CDC/ACIP, "Zoster (Shingles) Vaccine Recommendations"; CDC, "Shingles Vaccination"
What to Know Before Vaccination
Before scheduling a dose, it can help to review what is generally known about the vaccine's side effects and who should discuss timing with a healthcare provider first.
- Common side effects. These typically include soreness at the injection site, fatigue, muscle pain, and headache, and usually resolve within a few days.[1]
- Possible contraindications. The vaccine may not be appropriate for people with a history of a severe allergic reaction to a previous dose or to any of its components.[1]
- Special populations. Adults who are pregnant, breastfeeding, or currently moderately or severely ill should talk with their healthcare provider about the appropriate timing for vaccination.[1]
[1] CDC, "Shingles Vaccination"; CDC, "Vaccine Considerations for Immunocompromised Adults"
※ Seek immediate medical care if you develop signs of a severe allergic reaction, such as difficulty breathing, hives, or swelling of the face or throat, after receiving the vaccine.
If you take prescription medications or manage a chronic health condition, talk with your healthcare provider or pharmacist before adding any new vaccine to your care plan.
What These Studies Don't Prove
Both studies described above are observational, meaning researchers reviewed existing health data rather than randomly assigning participants to receive the vaccine or a placebo.[1] This design cannot rule out confounding factors — for example, adults who choose to get vaccinated may also be more likely to see a doctor regularly, follow other preventive health recommendations, or have fewer underlying health conditions overall, any of which could independently be linked to lower dementia risk.[1]
[1] Hayes et al., Annals of Internal Medicine (2026); dos Reis et al., Alzheimer's & Dementia (2026)
These findings show an association between shingles vaccination and lower rates of dementia diagnosis — they do not prove that the vaccine prevents or reduces the risk of dementia. Large randomized controlled trials, which are generally considered the strongest form of evidence for cause-and-effect relationships, have not yet been conducted to test this specific question directly. Until that kind of research is available, the connection between the shingles vaccine and dementia risk is best regarded as an area of active scientific interest rather than an established medical benefit.
Frequently Asked Questions
Does getting the shingles vaccine prevent dementia?
No. Shingles vaccination is associated with lower rates of dementia diagnosis, not a confirmed cause-and-effect relationship.[1] Large, controlled studies have not yet confirmed that the vaccine directly prevents or reduces dementia risk.
[1] Hayes et al., Annals of Internal Medicine (2026); dos Reis et al., Alzheimer's & Dementia (2026)
Who is currently recommended to get the shingles vaccine?
The CDC recommends Shingrix for adults 50 and older, as well as for adults 19 and older with weakened immune systems.[1] This recommendation is based on the vaccine's effectiveness at preventing shingles, not on the dementia-related findings discussed above.
[1] CDC/ACIP, "Zoster (Shingles) Vaccine Recommendations"
Should I get the shingles vaccine specifically to lower my dementia risk?
Talk with your healthcare provider about your personal health history and vaccination status. The shingles vaccine may offer additional benefits that are still under study, but it is approved and recommended primarily for preventing shingles and its complications, not for reducing dementia risk.
Are these study results considered final?
No. Researchers describe results like these as preliminary and in need of confirmation through additional studies, including randomized controlled trials, before firm conclusions about dementia risk can be drawn.
References
- Hayes KN, et al. (2026). "Dementia Risk After Recombinant Herpes Zoster Vaccination in Older Adults With a Recent Skilled-Nursing Facility Stay: A Target Trial Emulation." Annals of Internal Medicine, 179(7):958. https://doi.org/10.7326/ANNALS-25-04689
- dos Reis S, et al. (2026). "Reduced risk of dementia with recombinant zoster vaccine in US adults age 65 or older." Alzheimer's & Dementia, 22:e71407. https://doi.org/10.1002/alz.71407
- Polisky V, et al. (2025). "Varicella-zoster virus reactivation and the risk of dementia." Nature Medicine, 31(12):4172-4179. https://doi.org/10.1038/s41591-025-03972-5
- Centers for Disease Control and Prevention. "Shingles Vaccination." https://www.cdc.gov/shingles/vaccines/index.html
- Centers for Disease Control and Prevention, ACIP. "Zoster (Shingles) Vaccine Recommendations." https://www.cdc.gov/acip-recs/hcp/vaccine-specific/shingles.html
- Centers for Disease Control and Prevention. "Vaccine Considerations for Immunocompromised Adults." https://www.cdc.gov/shingles/hcp/vaccine-considerations/immunocompromised-adults.html
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