By Budi Oetomo Narendra 
People living with established atherosclerotic heart disease who received a shingles vaccine experienced nearly half the rate of serious heart-related events within a year compared with those who were not vaccinated, according to groundbreaking findings presented at the American College of Cardiology’s Annual Scientific Session (ACC.26). This significant reduction underscores the potential for widely recommended vaccinations to offer protective benefits far beyond their primary targets, opening new avenues for preventive care in vulnerable populations.
The research, drawing from a vast dataset of over 246,822 adults in the United States diagnosed with atherosclerotic heart disease (ASCVD), provides compelling evidence that the shingles vaccine may serve as a crucial adjunctive therapy in managing cardiovascular risk. Atherosclerotic heart disease, characterized by the dangerous buildup of plaque in the arteries, is a leading cause of morbidity and mortality globally, making any intervention that can mitigate its severe outcomes highly impactful. The study’s results add substantial weight to a growing body of scientific literature suggesting that the shingles vaccine, primarily known for preventing the painful rash of herpes zoster, may confer broader health advantages, including a reduced risk of serious conditions such as heart disease and even neurodegenerative disorders like dementia.
Dr. Robert Nguyen, a resident physician at the University of California, Riverside, and the lead author of the study, emphasized the cumulative evidence. "This vaccine has been found over and over again to have cardioprotective effects for reducing heart attack, stroke, and death," Dr. Nguyen stated. "Looking at the highest risk population, those with existing cardiovascular disease, these protective effects might be even greater than among the general public." His comments highlight the profound implications for a patient group already facing heightened risks of adverse cardiac events.
The Mechanisms Behind Cardioprotection: Unraveling the Link Between Shingles and Heart Health
To understand why a vaccine designed to prevent a painful skin rash might protect the heart, it’s essential to delve into the pathophysiology of shingles and its systemic effects. Shingles, or herpes zoster, is caused by the reactivation of the varicella-zoster virus (VZV), the same virus responsible for chickenpox. After an initial chickenpox infection, VZV lies dormant in nerve cells and can reactivate years later, typically in individuals over 50 or those with weakened immune systems. This reactivation leads to a distinctive, often excruciatingly painful rash, which can be followed by long-lasting nerve pain known as postherpetic neuralgia (PHN). The Centers for Disease Control and Prevention (CDC) currently recommends the shingles vaccine for adults age 50 years and older, as well as younger individuals with compromised immune systems.
Earlier research has illuminated a critical connection between shingles infections and cardiovascular health. Acute shingles episodes are not merely localized skin conditions; they can trigger a cascade of systemic inflammatory responses. This inflammation, coupled with direct viral effects on blood vessels, has been shown to promote the formation of blood clots, particularly near vital organs like the brain and heart. This prothrombotic state significantly increases the immediate and short-term risk of severe cardiovascular events, including heart attacks (myocardial infarction), strokes (cerebrovascular accident), and venous thromboembolism (VTE). By effectively preventing shingles, the vaccine disrupts this inflammatory cascade, thereby potentially reducing the likelihood of these dangerous clotting events and subsequent cardiac complications. The current study provides robust epidemiological support for this hypothesized mechanism, translating theoretical understanding into tangible clinical outcomes.
A Large-Scale Investigation: Methodology and Significant Findings
The study leveraged TriNetX, a comprehensive federated research network that aggregates de-identified electronic medical records from millions of Americans across numerous healthcare organizations. This expansive database allowed researchers to conduct a robust, real-world analysis. The investigation specifically focused on adults aged 50 years or older diagnosed with atherosclerotic disease, examining data collected between 2018 and 2025.
To ensure the validity of their comparisons, the researchers meticulously matched two cohorts: 123,411 individuals who had received at least one dose of either the Shingrix or Zostavax vaccine and an equal number of unvaccinated individuals. Both groups were carefully balanced based on a wide array of demographic factors (age, sex, race, ethnicity) and critical health conditions (e.g., diabetes, hypertension, hyperlipidemia, smoking status, chronic kidney disease, prior cardiovascular events). This rigorous matching process aimed to minimize confounding factors, thereby isolating the effect of vaccination.
The primary focus of the study was on heart-related outcomes occurring between one month and one year after vaccination (or within the equivalent timeframe for the unvaccinated control group). The results were strikingly consistent across all measured cardiovascular endpoints, demonstrating significantly lower risks for vaccinated individuals. Specifically, those who received the shingles vaccine were:
- 46% less likely to experience a major adverse cardiac event (MACE), a composite outcome typically including heart attack, stroke, and cardiovascular death.
- 66% less likely to die from any cause within the observation period, highlighting a broader protective effect on overall mortality.
- 32% less likely to suffer a heart attack.
- 25% less likely to experience a stroke.
- 25% less likely to develop heart failure.
These reductions are not merely statistically significant but clinically meaningful. Dr. Nguyen underscored their magnitude, noting that these benefits are "substantial and comparable to the benefits seen from quitting smoking," a widely recognized and impactful lifestyle intervention for cardiovascular health. He reiterated that these findings strongly reinforce current public health recommendations for adults over age 50 to receive the shingles vaccine.
The Shingles Vaccine Landscape: Evolution and Efficacy
The landscape of shingles vaccination has evolved over the past two decades. The first shingles vaccine, Zostavax, a live attenuated vaccine, was approved by the U.S. Food and Drug Administration (FDA) in 2006. While effective, its efficacy waned over time, and it was contraindicated in immunocompromised individuals. Its successor, Shingrix, a recombinant subunit vaccine, received FDA approval in 2017. Shingrix quickly became the preferred vaccine due to its superior efficacy and durability. Clinical trials demonstrated Shingrix to be over 90% effective in preventing shingles in adults 50 years and older, with sustained protection for at least seven years, and it is safe for most immunocompromised individuals. The current study included both vaccine types, reflecting real-world vaccination practices during the study period, with Shingrix being the predominant vaccine administered in later years. The consistent benefits observed across the vaccinated cohort, regardless of the specific vaccine, further strengthens the overall conclusion regarding shingles vaccination.
Broader Implications and Public Health Imperatives
The implications of this research extend far beyond individual patient care, touching upon public health policy, healthcare economics, and the ongoing battle against misinformation. Cardiovascular diseases remain the leading cause of death globally, accounting for an estimated 17.9 million lives each year, according to the World Health Organization. In the United States alone, approximately 6.2 million adults have heart failure, and someone has a heart attack every 40 seconds. The economic burden is staggering, with direct and indirect costs exceeding hundreds of billions of dollars annually. Any intervention, especially one already widely available and recommended, that can substantially reduce these numbers represents a massive public health victory.
Dr. Nguyen’s statement regarding patient hesitancy in an "age of disinformation" resonates deeply within the current healthcare environment. "Vaccines are one of the most important medicines we have to prevent disease," he stated. "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." This research provides a powerful, evidence-based argument for healthcare providers to use in their discussions with eligible patients, particularly those with existing cardiovascular disease who stand to gain the most.
The findings could potentially influence future clinical guidelines from major cardiology organizations like the American Heart Association (AHA) and the American College of Cardiology (ACC). While the CDC already recommends shingles vaccination, explicit endorsement within cardiovascular disease management guidelines could significantly boost uptake among a critical population. Primary care physicians and cardiologists might increasingly incorporate shingles vaccine discussions into routine ASCVD management, similar to how flu vaccination is often recommended for heart patients.
Acknowledging Limitations and Charting Future Research
Like all observational studies, this research has certain limitations that warrant consideration. The analysis tracked outcomes only during the first year after vaccination, meaning the long-term effects of shingles vaccination on cardiovascular events in this high-risk population remain to be fully elucidated. However, a previous landmark study published in 2025 demonstrated that shingles vaccination was associated with a 23% reduction in cardiovascular events in generally healthy adults, with benefits potentially lasting up to eight years, suggesting that the protective effects observed in the current study could persist or even amplify over time.
Another inherent limitation of observational studies is the potential for "healthy user bias." Individuals who choose to get vaccinated may inherently engage in healthier behaviors overall, such as regular exercise, a balanced diet, and adherence to medical advice. While the researchers made considerable efforts to mitigate this bias by adjusting for a comprehensive list of health and socioeconomic factors (including housing stability, economic circumstances, social environment, employment status, education, and literacy), it is still possible that some unmeasured confounding factors influenced the observed benefits.
Despite these limitations, the study’s strengths are considerable. Its exceptionally large sample size, robust statistical methodology, and the use of a real-world, diverse patient database lend significant credibility to its conclusions. The consistent and substantial risk reductions observed across multiple cardiovascular outcomes provide compelling evidence that shingles vaccination is indeed associated with a meaningful and clinically relevant reduction in heart disease risk for those already living with ASCVD.
Conclusion: A New Tool in the Cardiovascular Prevention Arsenal
The presentation of "Herpes Zoster Vaccination and Risk of Cardiovascular Events in Patients with Atherosclerotic Cardiovascular Disease" by Dr. Nguyen at ACC.26 on Monday, March 30, at 12:30 p.m. CT / 17:30 UTC in Posters, Hall E, marks a pivotal moment in preventive cardiology. These findings not only underscore the importance of adherence to existing vaccination schedules but also reveal an unexpected yet powerful weapon in the ongoing fight against heart disease. For individuals with atherosclerotic cardiovascular disease, the shingles vaccine appears to be more than just protection against a painful rash; it may be a vital shield for their hearts, offering a compelling reason for patients and providers alike to prioritize its administration. As research continues to uncover the pleiotropic effects of vaccines, this study serves as a potent reminder of their profound, multifaceted impact on public health.