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

CATEGORY: DISEASE PREVENTION

Veterans who took the 2024-25 COVID-19 vaccine at the same visit as their flu shot had a 38% lower risk of a COVID-related heart attack, stroke, heart-failure hospitalization or cardiovascular death over the next eight months. That comes to about 2 fewer such events per 10,000 people, in a study of just over one million US veterans.¹ The association was clearest above age 75, and below 65 it did not reach statistical significance.

One Vaccination Visit, Two Paths, Eight Months of Records

Everyone in the study turned up for a flu vaccine at a Veterans Affairs facility in the fall of 2024. About a third of them, 349,085 veterans, also took the updated COVID-19 vaccine at that same visit. The other 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 showed up for a vaccine narrows the familiar gap between vaccine seekers and vaccine skippers. It does not close it. Nobody was randomized here, so the study can show association and not cause. The team named its open question up front: earlier COVID-19 vaccines had been shown to lower these heart risks, but whether an updated one still would, with variants evolved and most people carrying 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, and the pattern underneath it matters more. Veterans older than 75 saw about a 51% lower risk, or 5.5 fewer events per 10,000 people. In veterans under 65, and in those between 65 and 75, the differences were not statistically significant.¹ People with chronic conditions such as kidney or lung disease gained more in absolute terms than healthier veterans did. 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 every seat held someone over 75. A large relative drop in a rare outcome is still a small change in any one person’s odds, and the study keeps both numbers in view.

Counting Every Heart Event Widened the Gap

When the researchers counted all major cardiovascular events, whether or not a COVID-19 infection appeared in the record, the vaccinated group had about 24 fewer events per 10,000 people. That is a far larger absolute difference than the COVID-labeled count alone.¹ Their reading is that many infections now go untested and unrecorded, so heart events following an unrecognized infection never get the label; the protection, they suggest, extends to that hidden burden. An Estonian study leans the same way. Among 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 The veterans here were 92% male, average age 70, so the findings travel best to older men and may describe women and younger adults poorly. However carefully two groups are matched, people who accept an extra vaccine may differ from those who decline it in ways health records cannot capture.¹

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 went 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, roughly 51% lower risk and 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 put part of that wider gap down to undetected infections.
• This is observational research in a group that was 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