Could the updated COVID-19 vaccine also lower heart attack and stroke risk?

Updated COVID shots are mainly meant to lower the odds of severe infection. But a large new U.S. study suggests they may also be linked to a lower risk of some serious heart and circulation problems after COVID.

That does not mean the vaccine acts like a heart drug, and it does not prove the shot directly prevents heart attacks or strokes. Still, the findings add to growing evidence that preventing or blunting COVID infection may also reduce some of the cardiovascular fallout that can follow it.

What the new study found

In a JAMA Internal Medicine study published June 15, 2026, researchers analyzed health records from 1,039,659 veterans who got a 2024-2025 flu shot through the Veterans Health Administration. Of those, 349,085 also got an updated COVID vaccine the same day, while 690,574 got a flu shot alone. Researchers then followed both groups for up to eight months.

The updated COVID vaccine was associated with a 37.7% lower relative risk of a COVID-associated major adverse cardiovascular event, a combined outcome that included cardiovascular death, heart attack, stroke, or hospitalization for heart failure. In absolute terms, the difference was much smaller: about 2 fewer COVID-associated major cardiovascular events per 10,000 people over eight months.

The paper also found lower rates of broader all-cause cardiovascular events, hospitalization, and death. Those secondary findings are interesting, but they are harder to interpret because they include events that were not necessarily tied to a confirmed COVID diagnosis.

Which heart outcomes seemed to change most

When the researchers separated the combined outcome into individual events, the clearest signals were for cardiovascular death, heart attack, and hospitalization for heart failure. The stroke finding did not reach statistical significance, which means the study could not rule out chance for that specific outcome.

The benefit also appeared strongest in people age 75 and older and in veterans with chronic health conditions. That fits with what doctors already know: people at higher risk from COVID tend to have more to gain from avoiding infection or severe illness.

Why this does not prove cause and effect

This was an observational study, not a randomized clinical trial. The researchers used a method called target-trial emulation, which tries to make real-world data behave more like a trial. Here, they compared people who got a flu shot plus a COVID shot on the same day with people who got a flu shot alone, which helps reduce some common biases.

Even so, observational studies cannot fully account for every difference between groups. The authors said residual confounding and misclassification are still possible. The study population was also mostly older, White, and male because it came from the VA system, so the results may not apply equally to everyone.

Why COVID can affect the heart in the first place

The heart connection is biologically plausible. NIH-backed research has found that COVID infection itself can raise the risk of heart attack, stroke, and death for years after infection in some groups. The American Heart Association has also highlighted evidence that viral infections, including COVID and flu, can sharply raise the short-term risk of heart attack or stroke in the weeks after illness.

That helps explain why a vaccine aimed at infection and severe disease could also be linked to fewer cardiovascular complications. In plain language: if COVID can strain the heart, preventing some infections or making them less severe may also lower some heart-related fallout.

How this fits with current U.S. guidance

CDC guidance for the 2025-2026 season says COVID vaccination is available for people ages 6 months and older through shared clinical decision-making. The agency says the risk-benefit balance is most favorable for people at higher risk for severe COVID. For adults 65 and older, the current CDC schedule includes two 2025-2026 doses, generally about six months apart, with minimum intervals depending on the product used.

That means this study does not create a new recommendation by itself. Instead, it gives people and clinicians another piece of information to consider, especially if someone is older, immunocompromised, has heart disease or several chronic conditions, or is deciding whether an updated dose is worth it.

What readers can do

If you are deciding about an updated COVID shot, consider your personal risk factors, including age, immune status, heart disease, lung disease, kidney disease, diabetes, and how often you are exposed to infection.
If you already have cardiovascular disease, ask your clinician or pharmacist how current COVID vaccination fits into your prevention plan.
Do not read this study as proof that a vaccine replaces blood pressure control, cholesterol treatment, exercise, smoking cessation, or other proven heart-protection steps.
Keep perspective on the size of the effect. The relative risk reduction looked meaningful, but the absolute number of prevented COVID-associated heart events was modest in the overall study population.

What remains uncertain

Important questions are still open. This study did not show that the vaccine directly protects the heart independent of its effect on infection. It also did not estimate variant-specific effects, did not measure vaccine adverse events in this analysis, and did not include a randomized comparison.

It is also possible that some of the broader, all-cause cardiovascular benefit seen in the paper reflects undiagnosed COVID infections in the community rather than a direct heart effect from vaccination itself. That interpretation is plausible, but it is still an interpretation, not proof.

When to seek emergency care

Get emergency help right away for possible heart attack or stroke symptoms, including chest pain or pressure, shortness of breath, fainting, sudden weakness on one side, facial droop, or sudden trouble speaking. Quick treatment matters.

Sources

Editorial note: Weence articles are researched from cited public-health, medical, regulatory, journal, and reputable news sources and may be drafted with AI assistance. They are checked for source support, clarity, and safety guardrails before publication.

This article is for general informational purposes only and is not medical advice. Research findings can be early or incomplete, and health guidance can change. Always talk with a qualified healthcare professional about personal symptoms, diagnosis, medications, vaccines, screenings, or treatment decisions. If you think you may have a medical emergency, call emergency services right away.