The study reviewed data from more than 246,822 adults in the United States diagnosed with atherosclerotic heart disease, which is caused by plaque buildup in the arteries. The results add to growing evidence that the shingles vaccine may offer benefits beyond preventing shingles, including a reduced risk of conditions like heart disease and even dementia.

“This vaccine has been found over and over again to have cardioprotective effects for reducing heart attack, stroke and death,” said Robert Nguyen, MD, a resident physician at the University of California, Riverside and the study’s lead author. “Looking at the highest risk population, those with existing cardiovascular disease, these protective effects might be even greater than among the general public.”

Why the Shingles Vaccine May Protect the Heart

The Centers for Disease Control and Prevention (CDC) recommends the shingles vaccine for adults age 50 years and older, as well as younger individuals with weakened immune systems. The vaccine protects against herpes zoster, a condition that causes a painful rash and can sometimes lead to long-lasting nerve pain. It develops when the virus responsible for chickenpox becomes active again in the body, often years after the original infection.

Earlier research has shown that shingles infections can trigger blood clot formation near the brain and heart, increasing the risk of heart attacks, strokes and venous thromboembolism. By preventing shingles, the vaccine may also help reduce the likelihood of these dangerous clotting events.

Large Study Shows Significant Risk Reduction

To conduct the study, researchers used TriNetX, a large database containing medical records from millions of Americans. They examined adults age 50 years or older with atherosclerotic disease between 2018-2025. The analysis included 123,411 people who had received at least one dose of the Shingrix or Zostavax vaccine and an equal number who had not been vaccinated. Both groups were similar in terms of demographics and other health conditions.

Researchers focused on heart-related outcomes occurring between one month and one year after vaccination (or the same timeframe for those who were not vaccinated). Across all measures, vaccinated individuals showed lower risk. They were 46% less likely to experience a major adverse cardiac event and 66% less likely to die from any cause. In addition, their risk of heart attack dropped by 32%, stroke by 25%, and heart failure by 25%.

Nguyen noted that these reductions are substantial and comparable to the benefits seen from quitting smoking. He added that the findings reinforce current recommendations for adults over age 50 to receive the vaccine.

“Vaccines are one of the most important medicines we have to prevent disease,” he said. “Sometimes patients are unsure about whether they should get a vaccine or not, particularly in an age of disinformation. These results provide another reason for them to elect to get the vaccine.”

Limitations and Long-Term Impact

The analysis only tracked outcomes during the first year after vaccination, so the long-term effects may differ. However, a previous study published in 2025 found that shingles vaccination was linked to a 23% reduction in cardiovascular events in generally healthy adults, with benefits that could last up to eight years.

One limitation is that people who choose to get vaccinated may also engage in healthier behaviors overall. While researchers adjusted for several health and socioeconomic factors (problems related to housing and economic circumstances, social environment, employment status, education and literacy), it is still possible that some of the observed benefit is influenced by these differences. Even so, the study’s large sample size and statistical approach provide strong evidence that shingles vaccination is associated with a meaningful reduction in heart risk.

Nguyen will present the study, “Herpes Zoster Vaccination and Risk of Cardiovascular Events in Patients with Atherosclerotic Cardiovascular Disease,” on Monday, March 30, at 12:30 p.m. CT / 17:30 UTC in Posters, Hall E.