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 new research. These compelling findings, set to be presented at the American College of Cardiology’s Annual Scientific Session (ACC.26), underscore a potentially significant, yet previously underappreciated, benefit of routine vaccination, extending beyond its primary role in preventing herpes zoster. The study adds substantial weight to the growing body of evidence suggesting that the shingles vaccine offers multifaceted protective effects, including a reduced risk of serious conditions such as heart disease and even cognitive decline. Understanding Atherosclerotic Heart Disease and Shingles Atherosclerotic heart disease (ASCVD) is a chronic, progressive condition caused by the buildup of plaque in the arteries, leading to narrowing and hardening of these crucial blood vessels. This process can restrict blood flow to the heart, brain, and other parts of the body, significantly increasing the risk of life-threatening events such as heart attacks, strokes, and heart failure. Globally, ASCVD remains the leading cause of morbidity and mortality, affecting millions and imposing an immense burden on healthcare systems. In the United States alone, an estimated 18.2 million adults aged 20 and older have coronary artery disease, a major form of ASCVD, with many more living with other manifestations like peripheral artery disease or cerebrovascular disease. Managing ASCVD typically involves a combination of lifestyle modifications, medications to control risk factors like high blood pressure and cholesterol, and sometimes surgical interventions. Shingles, medically known as herpes zoster, is a painful viral infection 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. Years or even decades later, often due to weakened immunity from aging, stress, illness, or certain medications, the virus can reactivate, traveling along nerve pathways to the skin and causing a characteristic blistering rash. This rash is typically accompanied by severe, burning, or tingling pain, which can sometimes persist for months or even years after the rash clears, a condition known as postherpetic neuralgia (PHN). The Centers for Disease Control and Prevention (CDC) recommends the shingles vaccine for all healthy adults age 50 years and older, as well as younger individuals with weakened immune systems, due to the high incidence and potential severity of the disease and its complications. The lifetime risk of developing shingles is approximately one in three for individuals in the U.S., with the risk increasing significantly with age. The Study’s Design and Methodology To investigate the potential cardioprotective effects of the shingles vaccine in a high-risk population, researchers leveraged TriNetX, a vast federated research network containing de-identified electronic medical records from millions of Americans across numerous healthcare organizations. This expansive database allowed for a robust analysis of real-world patient data. The study focused on adults aged 50 years or older diagnosed with atherosclerotic disease, examining medical records collected between 2018 and 2025. The analysis meticulously constructed two balanced cohorts: 123,411 individuals who had received at least one dose of either the Shingrix or Zostavax vaccine, and an equal number of individuals who had not been vaccinated. The researchers employed advanced statistical matching techniques to ensure that both groups were highly similar across a comprehensive range of demographic variables and pre-existing health conditions. This included factors such as age, sex, race, ethnicity, socioeconomic status indicators (e.g., housing, employment, education), and common cardiovascular risk factors like hypertension, diabetes, hyperlipidemia, obesity, and smoking status. By carefully balancing these variables, the study aimed to minimize the influence of confounding factors, such as the "healthy user bias" – the tendency for vaccinated individuals to also engage in other healthier behaviors. The primary objective of the research was to assess the incidence of heart-related outcomes within a specific timeframe. Researchers meticulously tracked major adverse cardiac events (MACE), which typically include a composite of heart attack, stroke, and cardiovascular death, as well as individual outcomes such as myocardial infarction (heart attack), ischemic stroke, and heart failure. The observation period for these outcomes spanned from one month to one year following vaccination (or an equivalent index date for the unvaccinated control group), allowing sufficient time for any potential protective effects to manifest while minimizing immediate post-vaccination reactions as confounding factors. Key Findings: A Significant Reduction in Cardiac Events The results of this extensive analysis were striking and statistically significant. Across all measured heart-related outcomes, vaccinated individuals demonstrated a substantially lower risk profile compared to their unvaccinated counterparts. Specifically, those who had received the shingles vaccine were: 46% less likely to experience a major adverse cardiac event (MACE). This composite outcome, encompassing heart attack, stroke, and cardiovascular death, represents a critical measure of overall cardiovascular health. 66% less likely to die from any cause. This remarkable reduction in all-cause mortality highlights a broad protective effect that extends beyond specific cardiac events. 32% less likely to suffer a heart attack (myocardial infarction). 25% less likely to experience an ischemic stroke. 25% less likely to develop heart failure. Robert Nguyen, MD, a resident physician at the University of California, Riverside, and the study’s lead author, emphasized the magnitude of these reductions. "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." He further noted that the observed risk reductions are substantial, comparable to the well-documented benefits seen from quitting smoking or effectively managing other major cardiovascular risk factors. These findings not only reinforce existing recommendations for adults over age 50 to receive the vaccine but also suggest a compelling additional incentive for adherence. The Biological Rationale: How Shingles Impacts Cardiovascular Health The mechanism by which shingles vaccination may protect the heart is an area of active scientific inquiry, but existing research offers plausible explanations. A shingles infection is not merely a localized skin condition; it represents an acute viral reactivation that can trigger systemic inflammatory responses throughout the body. The varicella-zoster virus, when reactivated, can cause direct damage to blood vessels (vasculitis), particularly the endothelial cells lining the inner surface of arteries. This endothelial dysfunction is a critical early step in the development and progression of atherosclerosis and can lead to plaque instability. Earlier research has consistently shown a temporal association between shingles infections and an increased risk of cardiovascular events. Studies have indicated that shingles can transiently increase the risk of blood clot formation (thrombosis) near the brain and heart. This pro-thrombotic state is believed to be mediated by the inflammatory cascade unleashed by the viral infection, which can activate platelets and alter coagulation pathways. Such changes can significantly elevate the likelihood of acute events like heart attacks, strokes, and venous thromboembolism (VTE) in the weeks and months following a shingles episode. By preventing the acute shingles infection, the vaccine effectively prevents this inflammatory and pro-thrombotic surge, thereby reducing the likelihood of these dangerous clotting events and their subsequent cardiovascular consequences. The chronic, low-grade inflammation associated with recurrent subclinical viral reactivations could also contribute to long-term atherosclerotic progression, which the vaccine may mitigate. A Broader Context: Previous Research and Vaccine Development The current study builds upon a growing body of evidence linking shingles and cardiovascular risk. Early epidemiological studies in the 2010s began to identify a statistically significant association between herpes zoster infection and an elevated risk of stroke and myocardial infarction, particularly in the first year post-infection. These studies often highlighted that the risk was highest in younger individuals and those with fewer traditional cardiovascular risk factors, suggesting a direct role for the viral infection itself. The development of shingles vaccines has its own chronology. 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. A significant advancement came with the approval of Shingrix in 2017. Shingrix is a recombinant subunit vaccine, containing a viral glycoprotein E antigen and an adjuvant system (AS01B), which significantly boosts the immune response. Clinical trials demonstrated Shingrix to be over 90% effective in preventing shingles across all age groups 50 and older, with sustained efficacy for at least a decade. The superior efficacy and broader applicability of Shingrix have largely replaced Zostavax in many countries, including the U.S. The concept of "vaccine pleiotropy," where vaccines offer benefits beyond their primary target, is not new. For instance, the influenza vaccine has been shown to reduce the risk of cardiovascular events in susceptible populations. This accumulating evidence for the shingles vaccine further reinforces the idea that vaccines can be powerful tools not just for preventing infectious diseases but also for mitigating the risk of non-communicable diseases, particularly in vulnerable populations. Indeed, a previous study published in 2025 indicated 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, providing an important long-term perspective that complements the current study’s one-year follow-up. Expert Perspectives and Public Health Implications The findings from Dr. Nguyen’s team are expected to resonate widely within the cardiology and public health communities. For cardiologists and primary care physicians, these results provide a compelling new reason to actively recommend the shingles vaccine to their patients, particularly those already grappling with atherosclerotic heart disease. The potential to prevent serious cardiovascular events in an already high-risk population represents a significant clinical advantage. "Vaccines are one of the most important medicines we have to prevent disease," Dr. Nguyen emphasized. "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 statement underscores the importance of clear, evidence-based communication in an era where vaccine hesitancy remains a public health challenge. The American College of Cardiology’s decision to feature this research at its annual scientific session highlights its perceived importance in advancing cardiovascular care. Leaders from the ACC are likely to view such findings as critical additions to the evolving understanding of cardiovascular prevention, potentially influencing future clinical practice guidelines. From a public health standpoint, integrating shingles vaccination into broader cardiovascular prevention strategies could yield substantial benefits. The economic burden of cardiovascular disease is enormous, encompassing direct medical costs and indirect costs from lost productivity. If shingles vaccination can reduce the incidence of heart attacks, strokes, and heart failure, it could lead to significant healthcare cost savings in addition to improving patient quality of life and longevity. Public health campaigns might increasingly emphasize these broader benefits to encourage higher vaccination rates, especially among at-risk demographics. Organizations like the American Heart Association (AHA) and the CDC could incorporate these findings into their educational materials and recommendations, further solidifying the vaccine’s role in comprehensive health management. Addressing Limitations and Future Directions While the study presents robust evidence, it is important to acknowledge certain limitations, as is standard practice in scientific research. The analysis primarily tracked outcomes during the first year after vaccination. While this period captured immediate protective effects, the long-term impact beyond one year warrants further investigation, though previous studies suggest sustained benefits. Another inherent challenge in observational studies of vaccination is the potential for "healthy user bias." Individuals who choose to get vaccinated may also be more health-conscious overall, engaging in healthier lifestyles, adhering better to medical advice, and having greater access to healthcare. While the researchers made considerable efforts to adjust for a wide array of demographic, socioeconomic, and health-related factors using sophisticated statistical methods, it is theoretically possible that some residual confounding by unmeasured factors could exist. However, the study’s massive sample size and rigorous statistical approach provide strong evidence that the observed association between shingles vaccination and a meaningful reduction in heart risk is robust. Future research directions could include randomized controlled trials (though challenging to conduct for vaccine effectiveness against non-primary endpoints), studies with longer follow-up periods, and investigations into the specific biological pathways involved in VZV-induced cardiovascular damage and its prevention by vaccination. Further analysis on specific subgroups, such as patients with different types or severities of ASCVD, could also provide more granular insights. Conclusion: Reinforcing the Importance of Vaccination The findings presented by Dr. Nguyen and his team at ACC.26 mark a significant step forward in understanding the far-reaching benefits of the shingles vaccine. For patients already living with the challenges of atherosclerotic heart disease, the prospect of nearly halving the risk of serious cardiac events through vaccination offers a powerful message of hope and a clear call to action. This study reinforces the fundamental principle that vaccines are not just shields against specific infectious agents, but increasingly recognized as vital components of holistic preventive medicine, capable of influencing long-term health outcomes in profound ways. As the medical community continues to battle misinformation and promote evidence-based care, these results serve as another compelling testament to the invaluable role of vaccination in protecting public health and improving the lives of millions. Dr. Nguyen will present the study, titled "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. Post navigation Cornell University Scientists Unveil Major Breakthrough Towards Safe, Reversible Nonhormonal Male Contraceptive
