Studies Link Shingles Vaccine to Better Brain, Heart Health

A pair of recent studies has found that the shingles vaccine may protect against more than just shingles—it may reduce the risk of dementia and heart issues, too.

One study, published in JAMA on April 23, found that older Australians who were eligible for a free live-attenuated shingles vaccine (called Zostavax) had a 1.8% lower chance of being diagnosed with dementia compared to their peers who weren’t eligible for the free shot.

Then, research published in the European Heart Journal in early May found that South Korean adults who received the Zostavax shot had a 23% overall lower risk of major cardiovascular events (including heart attack and heart failure, among other issues).

The reason why, in both cases, could be due to the shingles vaccine’s ability to tamp down inflammation that would otherwise accompany an infection, experts explained.

“Vaccines can have effects on the immune system that are broader than just eliciting the specific antibody response for which they have been designed,” said Pascal Geldsetzer, MD, PhD, MPH, assistant professor of primary care and population health at Stanford University. “Broader immunological effects can have benefits for other diseases.”

Shingles is the common name for a viral infection called herpes zoster. People get shingles when the varicella-zoster virus (VZV), or chickenpox, reactivates in their bodies later in life. It typically manifests as a painful or itchy rash around the right or left side of the body.

Chickenpox cases in the U.S. have dropped by 97% since the varicella vaccine was introduced in 1995. However, for those who contracted VZV, the virus lingers in the body and “remains dormant in our nerves for the rest of our lives,” Richard Martinello, MD, professor of infectious disease and pediatrics at the Yale School of Medicine, told Health.

It’s not totally clear why VZV “reawakens” in some people’s bodies, though stress seems to be a common catalyst.

Shingles is also more commonly seen in:

Because of this, the shingles vaccine is recommended for all adults over the age of 50, plus younger adults who are immunocompromised, to prevent the illness.

Importantly, the Centers for Disease Control and Prevention (CDC) recommend people get the Shingrix vaccine, which is different than the Zostavax vaccine, used in both of the recent studies. Zostavax use was discontinued in the U.S. in 2020, as the vaccine’s efficacy was found to wane significantly over the years after people got the shot.

The researchers studied Zostavax because Shingrix hadn’t yet been approved or made available to patients in Australia and South Korea while the research was ongoing.

The April JAMA study included electronic health data from over 101,000 people living in Australia. Participants were about 63 years old on average, and they were followed for 7.4 years.

In November 2016, Australia made the Zostavax shot freely available to people born after Nov. 2, 1936. That meant researchers could follow participants close in age who were both eligible and ineligible for the vaccine to see if their incidence of dementia was different.

Results showed participants with expanded access to Zosavax had a significantly lower chance of being diagnosed with dementia.

“For the first time, we now have evidence that likely shows a cause-and-effect relationship between shingles vaccination and dementia prevention,” Geldsetzer, the study’s senior author, told Health. “We find these protective effects to be large in size—substantially larger than those of existing pharmacological tools for dementia.”

The study joins a growing body of research indicating that viruses that “hibernate in your nervous system” may be linked to the development of cognitive issues later on, Geldsetzer said.

As VZV lies dormant in the body, Martinello explained, it may affect the brain’s function by causing:

So, as Geldsetzer and his colleagues’ new study suggests, blocking these infections may be able to mitigate risk. A study published in Nature in April similarly found a reduced dementia incidence in people who received the shingles vaccine.

On the heels of this dementia study, researchers in South Korea found that the shingles vaccine is associated with heart health benefits, too.

The study relied on national health system data from about 2.2 million Korean adults, including over 1 million who received a live shingles vaccine like Zostavax.

Comparing heart health outcomes between unvaccinated and vaccinated people over the course of about six years, the researchers found that getting a shingles shot led to:

• A 26% lower risk of major cardiovascular events (including stroke, heart attack, or death from heart disease)
• A 26% reduced risk of heart failure
• A 22% lower risk of coronary heart disease

The decreased risk was especially pronounced in men younger than age 60, people with “unhealthy lifestyle habits,” those in low-income households, and people living in rural locations.

The data also showed that these protective benefits were strongest two to three years after vaccination but lasted for up to eight years.

“It takes time for the body to build up a strong immune response,” study author Kyeongmin Lee, PhD, a researcher at the Kyung Hee University Medical Center in Seoul, told Health. “We also know that vaccine-induced immunity tends to decline gradually over time.”

Though this study simply “cannot claim a direct cause-and-effect relationship” between shingles vaccination and heart health, there are some potential explanations for what’s going on, Lee explained.

“Shingles infection has been associated with inflammation and clot formation in blood vessels, both of which contribute to cardiovascular events,” Lee said. “By preventing the shingles infection, the vaccine likely reduces this inflammatory response, thereby lowering the risk of heart disease.”

The results of these studies indicate that the benefits of a shingles vaccine may extend beyond preventing the infection itself. But it’s important to remember that the shots older Americans are currently encouraged to get are not the same as the ones included in the studies.

Unlike Zostavax, the recommended Shingrix is a recombinant vaccine, meaning it contains proteins extracted from VZV, but no actual live virus.

“While the newer Shingrix vaccine was not studied, and that’s a clear limitation of these studies, it’s plausible the Shingrix vaccine may be as good or potentially even better [at] keeping people from having heart attacks and strokes, or developing dementia,” Martinello said.

Research has shown that, in healthy adults, Shingrix is:

• 97% effective in people ages 50 to 69
• 91% effective in people 70 and older

CDC data from 2019 suggested that only 26% of adults over the age of 50 have ever gotten a shingles vaccine.