Overview
- A JAMA Internal Medicine analysis of VA electronic health records published in mid-June examined 1,039,659 veterans and found receipt of the 2024–2025 COVID vaccine was associated with about a 38% lower risk of COVID‑associated major adverse cardiovascular events, a category that includes heart attack, stroke, cardiovascular death, and hospitalization for heart failure.
- The study also found an unexpected near 24% reduction in all‑cause major cardiac events without a documented COVID diagnosis, and investigators say unrecognized or untested SARS‑CoV‑2 infections could explain some of that larger effect.
- In absolute terms the benefit was small for individuals: researchers estimated COVID‑linked MACE fell from about 5 events per 10,000 people to about 3 per 10,000 over eight months, and authors calculated that, if causal, this might prevent thousands of cardiac events and deaths per 1 million people each year.
- Separate mid‑June analyses from CDC‑led U.S. researchers and a European study reinforce protection against severe illness, reporting roughly 41% effectiveness against critical COVID illness in adults and about 55% protection from symptomatic disease in older Europeans in the months after vaccination.
- All studies are observational and limited by changing testing practices, population immunity, and the VA cohort’s demographics, and experts note low uptake of updated shots among older adults represents a missed prevention opportunity even as randomized trials are urged to confirm causation and quantify net benefit.