Study: Vaccine for Herpes Zoster (Shingles) May Help Prevent or Delay Dementia

A recent study from Wales provides evidence that the herpes zoster (shingles) vaccine may help to prevent or delay the development of dementia.[1] Shingles is a painful rash illness caused by reactivation of the varicella-zoster virus that causes chickenpox.

Approved by the Food and Drug Administration in 2017, SHINGRIX is a recombinant vaccine whose antigen component is a single surface protein of the varicella-zoster virus.[2] The vaccine is not indicated to prevent chickenpox.

According to the study, “receiving the zoster vaccine reduced the probability of a new dementia diagnosis over a follow-up period of 7 years by 3.5 percentage points…corresponding to a 20.0%...relative reduction” in the risk of developing dementia. The protective effect observed was stronger in women than in men. The study used large-scale electronic health-record data and was published online in April 2025 in Nature, a leading science journal.

The Centers for Disease Control and Prevention[3] and Public Citizen’s Health Research Group[4] recommend two doses of a zoster vaccine (Shingrix) for adults aged 50 years and older. The vaccine is also recommended for adults aged 18 years and older who have weakened immune systems.

Background on shingles

Shingles typically attacks one segment of the body, causing a painful, blistering, itchy rash that lasts seven to 10 days.[5] Although the episodes frequently resolve without treatment, some people develop postherpetic neuralgia, a type of nerve pain that can be debilitating and persist for months. Severe cases of shingles on the face can cause vision or hearing loss, and very rarely cases can lead to pneumonia, brain inflammation and death. Each year about one million people in the United States will have a shingles attack; the lifetime incidence is about one in three people.[6]

Background on the zoster vaccine

The effectiveness of the zoster vaccine available in the U.S. has been demonstrated in several randomized clinical trials involving healthy and immune-compromised participants.[7] For example, one trial involving approximately 14,800 individuals who were 50-69 years old found the vaccine was 97% effective at preventing shingles and 100% effective at preventing postherpetic neuralgia. Separate studies in people who were immune compromised because of recent stem cell transplantation or blood cancer treatment showed lower effectiveness (68-89%).

Similar to other vaccines, the zoster vaccine typically has short-term mild to moderate adverse effects, including pain at the injection site, muscle aches, fever and headache.[8] Overall, within one year of vaccination, no serious adverse events have differentiated the vaccine from placebo. One post-marketing study found that Guillain-Barre syndrome (an autoimmune nerve disorder) was slightly more common (three cases per million) in people receiving Shingrix than in those receiving a placebo.

The new study[9]

Dementia is the general term for loss of memory, language and thinking abilities (such as the ability to solve problems) that is severe enough to interfere with activities of daily life. The most common form of dementia is Alzheimer’s disease.[10]

Evidence has emerged in recent years that herpes viruses that infect nerve cells, such as the varicella-zoster virus, may have a role in the development of dementia.[11]

The Nature study reviewed the electronic health records of more than 282,000 adults in Wales who were born between 1925 and 1942, were alive in 2013, and did not have dementia (sample included approximately 79% of that population). On Sept. 2, 2013, health authorities in Wales made a zoster vaccine available to people younger than 80; adults 80 years and older on that date were not eligible and remained ineligible for life.

This vaccine-eligibility cutoff birthdate approach created two otherwise comparable populations: one population with high uptake of the vaccine (47%) and another, slightly older population with essentially no uptake (0.01%). The researchers used comparisons of these two nearly identical populations to consider whether vaccine use was associated with the prevention of dementia. In the analytic sample, 45% of the adults were male and 12% had previously had shingles.

Over seven years of follow-up, more than 35,300 cases of dementia were diagnosed. After using statistical methods to adjust for the slight variation in age across subjects and other factors, the researchers found substantial differences between vaccinated and unvaccinated individuals in the frequency of a new dementia diagnosis. Shingles vaccination was associated with a 3.5% reduction in the probability of a dementia diagnosis, which corresponded to a 20% relative risk reduction.

Other analyses using these same data and methods found that receipt of the zoster vaccine was protective against shingles; vaccination was associated with a 2.3% reduction in the risk of developing shingles.

The researchers also found that receipt of the shingles vaccine did not correlate with uptake of other preventative services, such as flu vaccination, use of statins or drugs to treat high blood pressure, or breast cancer screening, or with the incidence of other leading causes of disability, such cardiovascular, kidney or rheumatologic diseases. These findings countered the possibility that increased use of health services more generally explained the reduction in subsequent dementia.

Additional, exploratory analyses revealed findings consistent with the theory that the shingles vaccine reduces the risk of dementia through immunological effects that target varicella virus reactivation. For example, multiple shingles episodes correlated with increased risk, whereas single episodes and antiviral treatment of shingles correlated with a reduced incidence of dementia. Moreover, the effect of zoster vaccination on new diagnoses of dementia was markedly greater among women than men. This finding was consistent with evidence from other vaccines about sex-based differences in vaccine effects.

Limitations of this study are that the data were collected from adults who were 79 or 80 years old and that the people in Wales received a different herpes zoster vaccine than the newer Shingrix vaccine that is available in the United States. Although the study was large and less vulnerable to bias than earlier research, it was not a randomized controlled trial with a placebo group.

What You Can Do

If you are immune compromised or older than 50 years and have not already received a herpes zoster vaccine, the Shingrix vaccine is recommended. Discuss with your clinician the best time to receive the vaccine. Although there is increasing evidence about the benefits of herpes zoster vaccination on dementia, further studies are required to fully understand the potential effects.
 

References

[1] Eyting M, Xie M, Michalik F, et al. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025 May;641(8062):438-446.

[2] GlaxoSmithKline Biologicals. Label: zoster vaccine recombinant, adjuvanted (SHINGRIX). March 2025. https://gskpro.com/content/dam/global/hcpportal/en_US/Prescribing_Information/Shingrix/pdf/SHINGRIX.PDF. Accessed June 6 2025.

[3] U.S. Centers for Disease Control and Prevention. Shingles vaccination. July 19, 2024. https://www.cdc.gov/shingles/vaccines/. Accessed June 5, 2025.

[4] A review of the shingles vaccine SHINGRIX. Worst Pills, Best Pills News. February 2022. https://www.worstpills.org/newsletters/view/1447. Accessed June 5, 2025.

[5] A review of the shingles vaccine SHINGRIX. Worst Pills, Best Pills News. February 2022. https://www.worstpills.org/newsletters/view/1447. Accessed June 6, 2025.

[6] U.S. Centers for Disease Control and Prevention. About shingles (herpes zoster). January 17, 2025. https://www.cdc.gov/shingles/about/. Accessed June 6, 2025.

[7] A review of the shingles vaccine SHINGRIX. Worst Pills, Best Pills News. February 2022. https://www.worstpills.org/newsletters/view/1447. Accessed June 6, 2025.

[8] Ibid.

[9] Ibid.

[10] U.S. Centers for Disease Control and Prevention. About dementia. August 17, 2024. https://www.cdc.gov/alzheimers-dementia/about/index.html. Accessed June 6, 2025.

[11] Eyting M, Xie M, Michalik F, et al. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025 May;641(8062):438-446.