COVID Vaccines Still Protect the Heart, New JAMA Study Finds
A large new study has confirmed that COVID vaccines continue to protect against serious heart events — including heart attacks and stroke — even as updated formulations have replaced earlier shots.
The findings, published June 15, 2026, in JAMA Internal Medicine, followed more than one million veterans at Veterans Affairs facilities in 2024, about a third of whom also received a COVID vaccine.
What The New COVID Heart Study Found
Researchers found COVID-vaccinated veterans had a roughly 38% lower risk of major cardiovascular events — including heart attacks, stroke, and cardiac death — over the eight months following vaccination.
The benefit was strongest among adults 75 and older and those with chronic conditions including kidney and lung disease.
STAT News reported that the finding held for both mRNA vaccines and other formulations.
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COVID vaccination was also tied to a nearly 24% reduction in all-cause cardiac events — not just those linked to a confirmed diagnosis — which could translate to prevention of approximately 3,500 major cardiac events and 2,400 deaths annually per one million people vaccinated.
Why Heart Events Occur Without A Confirmed Diagnosis
Study lead author Dr. Ziyad Al-Aly, a clinical researcher at Washington University in St. Louis, offered a direct explanation.
Many people experience mild COVID infections, do not test, and never receive a diagnosis — but the virus can still trigger cardiac inflammation and damage in the weeks that follow.
JAMA Internal Medicine published Al-Aly's findings alongside commentary from Dr. Robert Califf, a cardiologist and former FDA Commissioner, who called the results consistent with a growing body of evidence linking vaccines to cardiovascular protection.
Al-Aly told STAT that COVID remains widely circulating — and often undetected.
"Much of it is unlinked or unattributed to SARS-CoV-2," he said, "because people are not testing."
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Two More Studies Published The Same Day
A separate JAMA Internal Medicine study, led by Ryan Wiegand at the CDC, found vaccine effectiveness against critical illness was 41% among vaccinated US adults 18 and older.
Bill Hanage, an epidemiology professor at Harvard, told STAT the updated COVID vaccines now perform comparably to flu vaccines — meaningful given flu has only recently overtaken COVID as the leading respiratory cause of death in the US.
A third study, funded by the European Centre for Disease Prevention and Control and published in JAMA Network Open, found approximately 55% effectiveness in adults 60 and older across multiple European countries in the 2025-2026 season.
The Myocarditis Question And The Risk Picture
Some vaccine hesitancy has centered on myocarditis — inflammation of the heart muscle — as a rare mRNA side effect.
Research has consistently found vaccine-related myocarditis to be significantly milder than myocarditis from COVID infection itself, occurring primarily in young men.
The Al-Aly study found that for older adults and those with underlying conditions, the protective benefits against cardiac events substantially outweigh this risk.
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What Experts Say People Should Do Now
Former FDA Commissioner Califf said the decision depends on risk profile.
For low-risk individuals, absolute benefits are smaller — but evidence consistently shows benefits outweigh risks.
For older adults and those with chronic conditions, he was direct: "for people who are high risk, definitely get the update."
Al-Aly was equally plain: "forgoing vaccinations, that's leaving a lot of protection on the table."
COVID vaccine uptake among older US adults sits at less than half the rate of flu vaccine uptake — despite the cardiovascular evidence across all three simultaneous JAMA studies.
Key Takeaways
- A new JAMA Internal Medicine study of more than 1 million veterans found COVID vaccines cut major cardiovascular event risk by 38%.
- Vaccinated adults also showed a 24% reduction in all-cause cardiac events, regardless of COVID diagnosis.
- This could prevent an estimated 3,500 cardiac events and 2,400 deaths annually per million vaccinated people.
- A separate CDC-led study found 41% effectiveness against critical illness in vaccinated US adults.
- A European study found 55% effectiveness against symptomatic disease in adults 60+ in the 2025-2026 season.
- Experts say high-risk adults should receive the updated COVID vaccine.
Sources
- STAT News
- JAMA Internal Medicine — Al-Aly study
- JAMA Internal Medicine — Wiegand/CDC study
- JAMA Network Open — European ECDC study
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Health & Lifestyle Editor
Emma Rhodes covers public health, wellness, medical breakthroughs, and lifestyle trends. She is committed to reporting health news that is accurate, clear, and actionable.
