Shingles vaccine cuts major cardiac events by 46% and deaths by 66% in high-risk patients

A new study has found that the shingles vaccine does something researchers did not originally design it to do: it substantially reduces the risk of major cardiac events in people already at high risk of heart disease. The numbers are striking. Within one year of vaccination, high-risk patients experienced 46% fewer major cardiac events and 66% fewer deaths compared to unvaccinated patients with similar risk profiles. Those are not marginal improvements. They are the kind of outcome differences that change clinical guidelines.

Shingles, caused by the reactivation of the varicella-zoster virus, is primarily known for producing a painful rash and nerve pain, sometimes lasting months after the rash clears. About one in three people in the United States will develop shingles at some point in their lives, according to the CDC. The approved recombinant vaccine, Shingrix, manufactured by GSK, has been recommended since 2017 for adults 50 and older. Its cardiac benefits were not part of that original rationale, which makes the new findings worth examining closely.

The biological mechanism researchers believe is at work

The leading hypothesis is that shingles infection triggers a cascade of clotting-related complications that can precipitate heart attacks and strokes in people whose cardiovascular systems are already under stress. The varicella-zoster virus is known to infect blood vessel walls directly. During a shingles episode, the virus can cause vascular inflammation, damage arterial endothelium, and promote platelet aggregation, which is the clustering of platelets that initiates clot formation. In a healthy person with clean, flexible arteries, this might not be enough to trigger a cardiac event. In someone with existing coronary artery disease or multiple cardiovascular risk factors, the additional inflammatory and clotting burden can push a vulnerable plaque toward rupture.

This mechanism is supported by earlier epidemiological data. A 2017 study published in the Journal of the American College of Cardiology found that shingles infection was associated with a 59% increased risk of heart attack and a 35% increased risk of stroke in the week following the acute illness. The new research builds on that foundation by showing the protective mirror image: preventing shingles through vaccination reduces the downstream cardiac risk in those most vulnerable to it.

Who was studied and how the data was collected

The study drew on a large retrospective cohort of patients with documented cardiovascular risk factors, including prior myocardial infarction, diabetes, hypertension, and chronic kidney disease. Researchers compared outcomes between patients who received the shingles vaccine and matched unvaccinated controls over a twelve-month follow-up period. The analysis controlled for age, sex, smoking status, statin use, and existing cardiovascular medications to isolate the vaccine's independent effect on outcomes.

The 66% reduction in deaths is the figure that will draw the most scrutiny, and appropriately so. A single retrospective study, even a well-controlled one, cannot definitively establish causation. Residual confounding is always possible in observational research, meaning that vaccinated patients might differ from unvaccinated patients in ways that the statistical controls did not fully capture. People who proactively seek vaccination may also be more engaged with their health care overall, which could translate into better management of their cardiovascular risk factors through mechanisms unrelated to the vaccine itself.

What the findings could mean for cardiac care guidelines

Vaccination rates for shingles remain lower than public health agencies would prefer. CDC data from 2022 showed that only about 34% of US adults aged 50 and older had received the two-dose Shingrix series. Among adults aged 50 to 64, coverage was even lower, around 26%. If the cardiac protection finding holds up in prospective trials, those vaccination rates become a direct cardiovascular health issue, not just a shingles prevention issue.

Cardiologists do not currently recommend shingles vaccination as part of cardiac risk management. That recommendation comes from infectious disease and general internal medicine guidelines. A dual-indication framing, where shingles vaccination is actively promoted to patients already enrolled in cardiac care programs, would require the kind of prospective clinical evidence that this study's authors say is the necessary next step. The American Heart Association has not yet issued a statement on the findings.

The broader question about vaccines and cardiovascular health

The shingles finding is part of a growing body of research examining how certain vaccines may offer cardiovascular benefits beyond their primary infectious disease targets. A 2021 study in the European Heart Journal found that influenza vaccination was associated with a 34% reduction in major adverse cardiovascular events in patients with coronary artery disease. A separate analysis published in Circulation in 2022 found that pneumococcal vaccination was associated with reduced hospitalization for heart failure. The common thread across these studies is that serious infections increase cardiovascular risk in vulnerable patients, and preventing those infections through vaccination reduces that risk.

The researchers behind the current study have called for a randomized controlled trial specifically designed to test the shingles vaccine's cardiac effects as a primary endpoint. Without that trial, the 46% and 66% figures will remain compelling but provisional. The research team is in discussions with cardiology centers in the UK, Australia, and the United States about a prospective study design, with an estimated start date in late 2026.