37.7% Heart Event Drop with COVID Vaccine Opens New Indication Potential

Biotech and pharma companies developing next-generation COVID vaccines may now have a new target: cardiovascular event reduction. The VA's robust findings, published in JAMA, demonstrate that updated mRNA vaccines confer substantial cardioprotection beyond their antiviral effects, potentially reshaping label claims and future trial endpoints.

A landmark study published in JAMA Internal Medicine on June 25, 2026, demonstrates that the 2024–2025 formulation of the COVID-19 vaccine significantly reduces the risk of major adverse cardiovascular events (MACE) among U.S. veterans. Analyzing health records from over one million veterans who received both the COVID-19 and influenza vaccines between September and December 2024, researchers at the U.S. Department of Veterans Affairs found a 37.7% reduction in COVID-related MACE—comprising heart attack, stroke, hospitalization for heart failure, and cardiovascular death—over an eight-month follow-up period. The protective effect was most pronounced in those aged 75 and older, who experienced a striking 50.7% decrease in risk, and individuals with chronic health conditions saw greater absolute risk reductions compared to their healthier counterparts.

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Department of Veterans Affairs found a 37.7% reduction in COVID-related MACE—comprising heart attack, stroke, hospitalization for heart failure, and cardiovascular death—over an eight-month follow-up period.

The study's design is particularly robust, addressing the longstanding 'healthy vaccinee bias' by restricting the comparator group to veterans who received only the influenza vaccine, thus ensuring both cohorts had similar health-seeking behaviors. Secondary analyses revealed even larger reductions in all-cause MACE, all-cause hospitalization, and all-cause death, suggesting the vaccine's benefits extend beyond preventing COVID-linked cardiac complications. These findings align with a growing body of evidence that vaccines against infectious diseases can dampen systemic inflammation—a key driver of cardiovascular events—by reducing the likelihood or severity of infection.

Dr. Glenn Hirsch, a cardiologist at National Jewish Health in Denver, contextualized the results, noting that they are 'not overall surprising' given that vaccination either blocks infection or mitigates its inflammatory consequences. Previous research has demonstrated that influenza vaccination alone can lower cardiovascular risk, and the COVID vaccines' mRNA technology may amplify this effect through transient immune activation that paradoxically entrenches long-term cardioprotection.

From a public health perspective, this study provides compelling ammunition for vaccination campaigns targeting populations at high cardiovascular risk—a group that overlaps substantially with those vulnerable to severe COVID-19. For healthcare systems, integrating COVID-19 vaccination into cardiac rehabilitation programs or routine visits for chronic disease management could yield substantial dividends in reducing costly cardiovascular events. The VA's integrated health system model, with its comprehensive electronic health records, offers a blueprint for other large care networks to monitor post-vaccination outcomes in real time.