The Centers for Disease Control and Prevention (CDC) advise that all individuals aged 50 and above receive two doses of the Shingrix vaccine. Recent research indicates that this vaccine might also help reduce the risk of cognitive decline.
Key Highlights:
- Individuals who received the Shingrix vaccine had a lower likelihood of developing dementia compared to those who were given an older vaccine.
- The newer Shingrix vaccine contains an inactivated version of the herpes zoster virus along with an immune-stimulating component.
- While the connection between shingles prevention and dementia protection remains uncertain, the findings are promising.
Protection Against Dementia?
A recent study has uncovered a surprising potential benefit of the shingles vaccine: protection against dementia. This groundbreaking research, published in Nature Medicine, examined over 200,000 participants and found that individuals who received the newer Shingrix vaccine were 17 percent less likely to develop dementia compared to those who received the older Zostavax vaccine. Maxime Taquet, BMBCh, PhD, the lead author of the study and a clinical lecturer in psychiatry at Oxford University, believes these findings could have significant implications for public health.
“If the findings are validated in clinical trials, it could have significant implications for older adults, health services, and public health,” says Dr. Taquet. “Dementia is an important public health challenge, with millions of people affected and without effective treatments to prevent or even delay its onset.”
Dementia, a devastating condition that affects cognitive function, impacts nearly 1 in 10 U.S. adults aged 65 and older. With the aging global population, preventing or delaying its onset has become a priority for health professionals and researchers alike.
The Shingrix Vaccine: A New Defense Against Dementia
Shingrix, introduced in 2017, replaced Zostavax as the preferred shingles vaccine in the United States due to its superior effectiveness. Unlike Zostavax, which contains live virus cells, Shingrix uses an inactivated form of the herpes zoster virus, along with an adjuvant, a substance that boosts the immune response. This key difference allowed researchers to compare the cognitive health outcomes of individuals receiving the two vaccines.
The study involved 201,064 participants with an average age of 71. About half of the participants were administered the Shingrix vaccine, while the rest received Zostavax. Researchers also compared those who had received vaccines for other infections, such as influenza, tetanus, diphtheria, and pertussis (whooping cough).
The study revealed the following key findings:
- Shingrix was associated with a 17 percent lower risk of dementia compared to Zostavax.
- When compared to other vaccines included in the study, Shingrix recipients had a 23 to 27 percent lower risk of dementia.
- Those who received Shingrix lived five to nine more months without dementia than those in the Zostavax group.
- Both men and women who received Shingrix showed a reduced risk of dementia, though women experienced a 9 percent greater protective effect.
Theories on How Shingrix May Reduce Dementia Risk
While the exact mechanism behind Shingrix’s ability to lower dementia risk is still unclear, Dr. Taquet offers two hypotheses. One possibility is that shingles itself could contribute to the onset of dementia. By preventing shingles, the vaccine could indirectly protect against cognitive decline. Another theory focuses on the immune-boosting adjuvant found in Shingrix, which may help protect the brain by stimulating the body’s immune response.
“It might be that this stimulation helps prevent dementia,” Dr. Taquet explains, emphasizing the need for further research to fully understand these results.
The study’s findings have sparked considerable interest in the scientific community, particularly among researchers studying the intersection of vaccination and cognitive health. Pascal Geldsetzer, MD, PhD, MPH, an assistant professor of medicine at Stanford University, acknowledges the study’s significance, though he notes that additional investigation is necessary.
“This study investigates a very important question, given the increasing evidence that shingles vaccination may have benefits for the dementia disease process,” says Dr. Geldsetzer, who led previous research on the shingles vaccine and dementia risk but was not involved in this latest study.
Potential Influencing Factors
Despite the promising findings, there are certain variables that could have impacted the study’s outcome. According to Dr. Geldsetzer, individuals who are more “health-motivated” might have postponed getting vaccinated with Zostavax, anticipating the availability of the more effective Shingrix vaccine. This behavior could skew the results, as these individuals may have been more proactive about their health in other ways, such as maintaining a healthier lifestyle, which could also reduce the risk of dementia.
“The authors are only able to account for such differences using information that is contained in electronic health record data,” says Dr. Geldsetzer. “Unfortunately, that misses many important factors, such as physical activity or dietary behaviors. The authors are very transparent about these limitations and, in my view, did the best they could with the data at hand.”
The Need for Further Research
Both Dr. Taquet and Dr. Geldsetzer agree that while this study presents compelling evidence, further research is required before any definitive conclusions can be drawn. Dr. Geldsetzer emphasizes the importance of conducting large-scale, randomized clinical trials to establish a clear link between shingles vaccination and reduced dementia risk.
“A large-scale randomized trial will be needed before we can be entirely confident that shingles vaccination really does reduce the risk of dementia,” says Dr. Geldsetzer.
Who Should Receive the Shingrix Vaccine?
Regardless of its potential dementia-preventing properties, health experts continue to recommend the Shingrix vaccine to older adults for its proven ability to prevent shingles. According to Dr. Taquet, individuals aged 50 and older should receive the vaccine if they are eligible.
“We do not recommend taking it solely because it might prevent dementia, even though this might serve as an additional incentive,” he adds.
The Centers for Disease Control and Prevention (CDC) advises that adults aged 50 and older receive two doses of Shingrix, spaced two to six months apart. Adults aged 19 and older with weakened immune systems due to illness or medical treatment should also receive two doses, with the second dose administered one to two months after the first, based on a doctor’s recommendation.
However, individuals with a history of severe allergic reactions to the vaccine, those who currently have shingles, and pregnant women are advised against receiving Shingrix. Additionally, people who have not had chickenpox or shingles should consult their healthcare provider before getting vaccinated.
Understanding the Connection Between Chickenpox and Shingles
Shingles and chickenpox are both caused by the varicella-zoster virus. After a person recovers from chickenpox, the virus remains dormant in the body, and it can reactivate later in life, causing shingles. Shingles, a painful condition that typically affects older adults or individuals with weakened immune systems, can have serious long-term effects if left untreated.
Health experts estimate that more than 99 percent of Americans born in 1980 or earlier have had chickenpox, even if they do not remember it. Since the varicella-zoster virus remains in the body for life, the risk of developing shingles—and possibly other complications like dementia—remains a concern for older adults.
Moving Forward
As research into the connections between shingles, vaccination, and cognitive health continues to develop, the findings of this study offer hope that widespread vaccination efforts could play a role in addressing the growing public health challenge posed by dementia. However, experts urge caution and further investigation to better understand the relationship between Shingrix and dementia prevention.
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