A new study has discovered that older adults who receive the shingles vaccine may lower their chances of developing dementia by 20% over the next seven years.
This research, published last month in the journal Nature, helps us understand the various factors that affect brain health as we age and what we can do to improve it.
“It’s a very robust finding,” Dr. Pascal Geldsetzer, a lead researcher of the study at Stanford University, told the Associated Press. He also mentioned that “women seem to benefit more,” which is crucial since they have a higher risk of dementia. Additionally, data from the Alzheimer’s Disease Research Studies Center shows that Black Americans, particularly Black women, are roughly 2-3 times more likely to be diagnosed with Alzheimer’s or related dementias than White Americans.
The study followed individuals in Wales who were around 80 years old when they received the first-generation shingles vaccine in 2013. Now, people in the U.S. who are 50 and older are encouraged to get newer vaccines like manufacturer GSK’s Shingrix, which is shown to be more effective against shingles than the earlier version.
According to Dr. Maria Nagel from the University of Colorado Anschutz Medical Campus, who researches viruses that affect the nervous system, these new findings provide yet another reason for people to get vaccinated.
She says that the shingles virus “is a risk for dementia and now we have an intervention that can decrease the risk.”
As the number of Alzheimer’s and other dementia cases rises among older adults, the study has also caught the attention of many medical professionals, particularly because there are very few effective treatments available for dementia.
Dr. Paul Harrison, a psychiatry professor at Oxford, emphasized the significance of the discovery, stating, “If you’re reducing the risk of dementia by 20 percent, that’s quite important in a public health context, given that we don’t really have much else at the moment that slows down the onset of dementia,” he told The New York Times.
Dr. Harrison wasn’t part of the new study, but he has conducted other research showing that shingles vaccines can reduce the risk of dementia as well.
Dr. Anupam Jena, a physician and health economist at Harvard, also highlighted that the study’s results are very significant.
“It’s pretty strong evidence,” he told The Times.
Jena did not take part in the study, but he reviewed it for Nature.
What Exactly is Shingles?
Shingles is caused by the same virus that leads to chickenpox in children, known as varicella-zoster. The virus can stay inactive in nerve cells for many years, and as people age and their immune systems weaken, the virus can reactivate, resulting in shingles.
Symptoms include burning, tingling, painful blisters and numbness, with nerve pain potentially becoming long-lasting and severely limiting.
Approximately 1 in 3 people in the U.S. will develop shingles (also known as herpes zoster) in their lifetime, according to CDC estimates.
To date, about one-third of eligible adults have received the shingles vaccine.
How Does the Shingles Vaccine Help Prevent Dementia?
While earlier studies have indicated that the shingles vaccine might lower dementia risk, they couldn’t rule out that vaccinated individuals often lead healthier lives, eat better or have more education, which could also reduce risk.
But, this new study appears to have accounted for many of those factors.
Geldsetzer explains that one of several ways shingles vaccines can help prevent dementia is by reducing the brain inflammation that’s linked to the shingles virus’s reactivation.
“Inflammation is a bad thing for many chronic diseases, including dementia,” he told The Times. “Reducing these reactivations and the accompanying inflammation may have benefits for dementia.”
Geldsetzer and his team at Stanford used the Wales experiment because it allowed shingles vaccinations for people with an age limit: those who were 80 or older on September 1, 2013 could not get vaccinated, but those who were still 79 could. By comparing seniors who just met this age cutoff to those who just missed it, they created a situation similar to a research study that randomly assigned similar people to receive the vaccine or not.
They examined more than 280,000 medical records and discovered that vaccination offered some protection against dementia, specifically with the first-generation vaccine, Zostavax.
Geldsetzer intends to investigate Zostavax further to determine if the vaccine type matters.
A key next step is to test whether the current vaccine, Shingrix, can help protect against dementia too, according to Nagel. Another research team recently found some evidence that it might.
Another possibility is that vaccines boost the immune system in a wide range, and the new study supports some of this. It found that women, who typically have more active immune systems and stronger vaccine responses than men, had better protection against dementia. Geldsetzer also noted that the vaccine was more effective in protecting people with autoimmune conditions and allergies from dementia as well.
Nagel believes that both theories could be right. Although she didn’t take part in the study – she has worked with GSK as a consultant – she points out that “there’s evidence for a direct effect as well as an indirect effect.” And last month, GSK announced a partnership with UK health officials to monitor the cognitive health of seniors as they get vaccinated.
She also highlighted that some studies indicate that other vaccines may benefit brain health as well. Since the shingles virus remains in the nerves, it stands to reason that the shingles vaccine could be particularly effective in preventing cognitive and memory problems.
Although the study did not differentiate between types of dementia, other research indicates that the shingles vaccine is more effective against Alzheimer’s than other dementias. Svetlana Ukraintseva, a biologist at Duke and coauthor of a recent study on Alzheimer’s, suggested in an interview with The Times that this could be due to some Alzheimer’s cases being linked to weaker immune systems.
“The effect of the shingles vaccine for Alzheimer’s disease is much more pronounced than for another dementia,” she said.
What are the Recommendations for the Shingles Vaccine?
Shingrix, the common vaccine given in the U.S., is given in two doses a few months apart. The CDC advises most individuals to start getting it at age 50, but younger adults with specific health issues that compromise their immune systems, including those who previously received an older shingles vaccine, should also consider it.
Common side effects are injection site pain and flu-like symptoms, such as fever and body aches. The CDC recommends postponing the shingles vaccine if you are currently sick with another virus, like the flu or COVID-19, until you recover.
Fewer than 40% of eligible people have actually received the vaccine.
The Final Takeaway
Geldsetzer observed that the Welsh participants were mostly white, but his team discovered similar dementia protection in more diverse groups by analyzing death certificates in England. They confirmed these findings in Australia, New Zealand and Canada as well.
“We just keep seeing this strong protective signal for dementia in dataset after dataset,” he said in a release.
Experts suggest further research is needed to find out if the protection lasts beyond seven years. Nonetheless, Harrison points out that with limited effective treatments for shingles, vaccines seem to offer “some of the strongest potential protective effects against dementia that we know of that are potentially usable in practice.”
