An Updated COVID Vaccine Went With Fewer Serious Heart Events in Older Veterans

CATEGORY: DISEASE PREVENTION

Veterans who received the 2024–25 COVID-19 vaccine at the same visit as their flu shot had a 38% lower risk of COVID-related heart attack, stroke, heart-failure hospitalization, or cardiovascular death over the next eight months—about 2 fewer events per 10,000 people—in a study of just over one million US veterans.¹ The association was clearest in those older than 75, and the study found no statistically significant benefit in veterans under 65.

One Vaccination Visit, Two Paths, Eight Months of Records

Everyone in the study got a flu vaccine at a Veterans Affairs facility in the fall of 2024. About a third—349,085 veterans—also received the updated COVID-19 vaccine at that same visit, while 690,574 did not. Researchers then followed both groups through the VA’s electronic health records for eight months, counting heart attacks, strokes, heart-failure hospitalizations, and cardiovascular deaths that occurred in connection with a COVID-19 infection.¹ Comparing only people who all showed up for a vaccine helps shrink the usual gap between vaccine seekers and vaccine skippers, though as an observational study it can still show only association, not proof of cause and effect. The researchers were explicit about their open question: earlier COVID-19 vaccines had been shown to lower these heart risks, but whether an updated vaccine still would—now that variants have evolved and most people carry some immunity—was unknown.

Where the Benefit Landed: Mostly After 75

The overall figure was a 37.7% lower risk of COVID-related cardiovascular events, but the pattern underneath it matters more. Veterans older than 75 saw about a 51% lower risk—5.5 fewer events per 10,000 people—while the differences in veterans under 65 and between 65 and 75 were not statistically significant.¹ People with chronic conditions such as kidney or lung disease gained more in absolute terms than healthier veterans. It helps to picture a sold-out 10,000-seat arena: over eight months, vaccination went along with about two serious COVID-related heart events in that crowd not happening—five or six if everyone in the arena were over 75. A large relative drop in a rare outcome is still a small change in any one person’s odds, and the study’s honest arithmetic keeps both numbers in view.

Counting Every Heart Event Made the Gap Wider

When the researchers counted all major cardiovascular events—whether or not a COVID-19 infection was documented—the vaccinated group had about 24 fewer events per 10,000 people, a far larger absolute difference than the COVID-labeled count alone.¹ The authors’ interpretation is that many infections now go untested and unrecorded, so some heart events that follow an unrecognized infection never get labeled as COVID-related; the vaccine’s protection, they suggest, extends to that hidden burden. This echoes what other groups have found: in an Estonian study of 33,554 adults aged 40 to 85 who caught COVID-19 between 2021 and 2023, those vaccinated before infection had a 29% lower rate of major cardiovascular events in the months that followed.²

Mostly Older Men, and Association Rather Than Proof

The study population was 92% male, with an average age of 70, so the findings travel best to older men and may not describe women or younger adults well. And however carefully the groups were matched, people who accept an extra vaccine may differ from those who decline it in ways records cannot fully capture.¹ What the study offers is a large, current look at a question many people weigh each fall—whether the updated COVID-19 vaccine still earns its place alongside the flu shot—and its answer is that for the oldest adults and those with chronic disease, the heart-related numbers leaned toward yes.

Key Takeaways

• Among just over a million veterans who got a flu shot in fall 2024, adding the updated COVID-19 vaccine at the same visit was associated with a 38% lower risk of COVID-related heart attack, stroke, heart-failure hospitalization, or cardiovascular death over eight months—about 2 fewer events per 10,000 people.
• The association was strongest after age 75 (about 51% lower risk, 5.5 fewer events per 10,000) and was not statistically significant below age 65.
• Counting all major cardiovascular events, vaccinated veterans had about 24 fewer per 10,000; the authors attribute part of that wider gap to undetected infections.
• This is an observational study of mostly older men—it shows association, not proven cause and effect.

References

1. Cai M, Xie Y, Al-Aly Z. 2024-2025 COVID-19 Vaccine and Major Adverse Cardiovascular Events Among US Veterans. JAMA Internal Medicine. 2026;186(8):988–999. link
2. Meister T, Maiväli Ü, Tenson K, et al. Dynamic effects of COVID-19 vaccination on major acute cardiovascular events and mortality following SARS-CoV-2 infection in a target trial emulation study. Scientific Reports. 2025;15(1):27530. link