Veterans’ Risk of Heart Attack, Stroke Fell by Up to 38% With COVID Vaccine

Research published in the journal JAMA Internal Medicine found that COVID-vaccinated veterans had nearly 24 percent fewer all-cause cardiac events — not just those linked to COVID infections. The result suggests that the vaccines may be broadly cardioprotective, according to the researchers.

The large study using VA health data found that COVID-19 vaccination significantly reduced the risk of heart attacks, strokes and other major cardiovascular events among veterans — including a reduction in cardiac events with no documented COVID diagnosis, a finding that surprised the researchers themselves.

The study, published June 15, 2026, in JAMA Internal Medicine, followed more than 1 million veterans who received flu vaccinations at VA health care facilities in 2024. Approximately a third of them also received a COVID vaccine. In the eight months following vaccination, veterans who received COVID vaccines had a roughly 38 percent lower risk of COVID-associated major cardiovascular events compared to those who did not. The protective effect was strongest for veterans ages 75 and older and those with chronic conditions including kidney and lung disease.

The more striking finding was what happened beyond documented COVID cases. COVID vaccination was associated with nearly a 24 percent reduction in all-cause cardiac events — heart attacks, strokes and related hospitalizations across the board, not just those in which a COVID diagnosis appeared in the record. The researchers estimate that at that rate, vaccination could prevent approximately 3,500 major cardiac events and 2,400 deaths annually per 1 million people.

Read More: Now Is the Best Time to Enroll in VA Health Care: Here’s Why

Key facts from the study of more than 1 million veterans who received flu vaccinations at VA facilities in 2024 and of whom approximately one-third also received a COVID vaccine:

• 38% lower risk of COVID-associated major cardiovascular events among vaccinated veterans
• 24% reduction in all-cause cardiac events regardless of documented COVID diagnosis
• Estimated impact: prevention of approximately 3,500 major cardiac events and 2,400 deaths annually per 1 million people
• Strongest protection: veterans aged 75 and older and those with chronic kidney or lung disease
• Both mRNA and non-mRNA COVID vaccines showed cardioprotective effects.
• Lead researcher: Ziyad Al-Aly, Washington University in St. Louis, via VA research data
• Study published: JAMA Internal Medicine, June 15, 2026

Why the Cardiac Benefit Extends Beyond Documented COVID Cases

The 24 percent reduction in all-cause cardiac events — across veterans with no COVID diagnosis in their record — was the finding that generated the most scientific interest. The lead researcher, Dr. Ziyad Al-Aly, a physician and clinical researcher at Washington University in St. Louis, offered an explanation grounded in how COVID cases are actually tracked in the current environment.

“There [is] still actually a tidal wave of SARS-CoV-2 that continues to circulate in the population,” Al-Aly said. “Much of it is only unrecognized, leading to heart problems. Much of it is unlinked or unattributed to SARS-CoV-2, because people are not testing.”

Al-Aly described situations in which patients who felt unwell but did not test for COVID later arrived at emergency rooms with cardiovascular events. Those events were logged as cardiac events with no COVID diagnosis — but the underlying cause may well have been an unrecognized SARS-CoV-2 infection. Vaccination that prevented that infection, or reduced its severity, would then appear in the data as preventing an all-cause cardiac event rather than a COVID-specific one.

Former FDA Commissioner Robert Califf, a cardiologist who wrote an accompanying commentary on the findings in JAMA Internal Medicine, told STAT that the broader cardioprotective pattern is consistent with a growing body of research on vaccines and chronic disease.

Read More: The VA Helped 37,000 Veterans Quit Tobacco With These Services

“There are many, many studies now that show that vaccinations of various types seem to reduce the risk of chronic diseases, including cardiovascular disease. This is not inconsistent with what the other studies have shown.”

Why This Matters for Veterans Specifically

The veteran population carries a disproportionately high burden of cardiovascular disease. Military service, particularly combat deployment, has documented associations with elevated rates of hypertension, heart disease and metabolic conditions driven by chronic stress, physical demands and exposures accumulated during service. Veterans with conditions such as chronic kidney disease, chronic obstructive pulmonary disease and diabetes — the groups who showed the strongest protective effect in the study — are heavily represented in the VA health care system.

COVID vaccination uptake among older adults has fallen significantly since the acute phase of the pandemic. The researchers note that current uptake in older adults is less than half the rate of flu vaccine uptake, a gap that the cardiac findings suggest carries real clinical consequences for a population that was already at elevated cardiovascular risk before COVID entered the picture.

“Forgoing vaccinations — that’s leaving a lot of protection on the table,” said Al-Aly on the implications for older adults and those with comorbidities.

The Myocarditis Question

One reason COVID vaccine uptake has declined, particularly among younger men, is concern about vaccine-associated myocarditis, inflammation of the heart muscle that was identified as a rare side effect of mRNA formulations, primarily in young males. The study’s findings do not eliminate that concern but provide important context.

Research has consistently found that vaccine-related myocarditis is significantly milder than myocarditis caused by actual COVID-19 infection. The cardiac risk from COVID infection itself, including the risk of long-term cardiovascular damage, substantially exceeds the risk associated with vaccination in the studied populations. The veteran cohort in this study skewed older and was not the demographic where vaccine-associated myocarditis risk is highest.

Additional Research Published Alongside the Study

Several other COVID-related studies published the same day in JAMA journals add context to the cardiac findings. A study led by Ryan Wiegand at the CDC evaluated the effectiveness of 2024-2025 COVID vaccines and found that among vaccinated adults 18 and older, vaccine effectiveness against critical illness was 41 percent, comparable in the short term to flu vaccine effectiveness, according to researchers not involved in the study.

A separate study funded by the European Centre for Disease Prevention and Control, published in JAMA Network Open, evaluated adults 60 and older across multiple European countries and found approximately 55 percent effectiveness in protecting against symptomatic COVID-19 in the two months following vaccination with updated 2025-2026 formulations.

COVID Vaccination and Veterans: Practical Guidance

Some findings to keep in mind:

• Veterans ages 75 and older and those with chronic kidney or lung disease showed the strongest cardioprotective effect in this study; these groups have the most to gain from staying current on COVID vaccination.
• Updated COVID vaccines are reformulated annually to match circulating strains, similar to flu vaccines; the 2025-2026 formulation showed approximately 55% effectiveness against symptomatic illness in European adults 60 and older.
• COVID vaccination is available at VA facilities and through most retail pharmacies at no cost to veterans enrolled in VA health care.
• Veterans with questions about their individual risk and benefit profile should discuss vaccination with their VA primary care provider.
• Veterans who have not received an updated COVID vaccine since 2024 should consider whether their health profile — particularly age and chronic conditions — puts them in the higher-benefit category identified by the study.

The study is observational rather than a randomized controlled trial, which the researchers acknowledge as a limitation. Califf noted to STAT that establishing causality with certainty would require the kind of large randomized trial that has not yet been conducted. What the VA data provides is a real-world picture of outcomes across a large, well-documented patient population — the kind of evidence that, while not definitive, carries weight precisely because of its scale and the quality of the VA’s longitudinal health records.