Heart Protection Endures: Updated COVID Vaccines Still Reduce Major Cardiac Risks

In an era where COVID-19 has transitioned from a global emergency to an endemic respiratory threat, public skepticism toward annual boosters remains high. Yet, a major new study published in JAMA Internal Medicine on June 15, 2026, delivers reassuring news for cardiovascular health: the 2024–2025 updated COVID-19 vaccines continue to provide meaningful protection against serious heart-related complications linked to the virus, even as the pathogen evolves and population immunity shifts.

Led by epidemiologist Ziyad Al-Aly and colleagues at the VA St. Louis Health Care System and Washington University in St. Louis, the research analyzed data from over 1 million U.S. veterans who received their seasonal flu shot in late 2024. About one-third (349,085) also received a concurrent 2024–2025 COVID-19 vaccine, while the rest served as a comparison group. Over an eight-month follow-up period, the findings highlight persistent cardioprotective benefits amid vaccine updates.

Understanding the Cardiovascular Risks of COVID-19

SARS-CoV-2 infection has long been associated with elevated risks of heart problems. The virus can trigger widespread inflammation, damage blood vessels, promote clotting, and directly affect heart muscle tissue. This leads to complications such as myocardial infarction (heart attack), stroke, heart failure hospitalizations, and cardiovascular death — collectively known as major adverse cardiovascular events (MACE).

Even mild or undiagnosed infections can contribute to these issues weeks or months later. In a world of widespread prior exposure and vaccination, many cases go untested, but the downstream effects on the heart remain a concern, particularly for older adults and those with comorbidities like diabetes, chronic kidney disease, lung disease, or existing cardiovascular conditions.

Key Findings: 38% Reduction in COVID-Linked Heart Events

The study found that recipients of the updated COVID-19 vaccine had a 38% lower risk of COVID-19-associated MACE compared to those who received only the flu shot. This translated to a reduction from roughly 5 events per 10,000 people to about 3 per 10,000 over eight months — an absolute benefit that is modest on a population scale but clinically meaningful for high-risk groups.

Benefits were especially pronounced in subgroups:

• Adults aged 75 and older.
• Those with underlying conditions such as chronic kidney disease, lung disease, or prior cardiovascular issues.

Subgroup analyses showed strong protection across categories, with vaccine effectiveness often exceeding 50% in the most vulnerable.

Surprisingly, the vaccines were also linked to a nearly 24% reduction in all-cause MACE (not just those tied to documented COVID-19 infections). This broader effect likely stems from protection against unrecognized or mild infections that still strain the cardiovascular system. Extrapolating to a population of 1 million, vaccination could avert thousands of major cardiac events and deaths annually.

Context Amid Evolving Virus and Vaccine Updates

Early in the pandemic, original COVID-19 vaccines dramatically reduced severe outcomes. As variants like Omicron emerged, vaccines were reformulated to better match circulating strains. Skeptics wondered whether these updates would maintain non-respiratory benefits like heart protection.

This VA study — alongside a companion CDC-led analysis in the same journal showing 35–41% effectiveness against hospitalization and critical illness — suggests the answer is yes. The protection holds despite high background immunity from prior infections and vaccinations.

Myocarditis and Pericarditis: Rare Risks, Mostly in Context

mRNA COVID-19 vaccines have been linked to rare cases of myocarditis (heart muscle inflammation) and pericarditis, primarily in adolescent and young adult males shortly after the second dose of earlier formulations. Rates have declined significantly with updated boosters (often in the low single digits per million doses), and vaccine-associated cases tend to be milder, with better recovery than infection-related myocarditis.

Experts consistently emphasize that the overall risk of heart complications is substantially higher from COVID-19 infection itself than from vaccination. Long-term follow-up studies on vaccine-associated myocarditis show generally favorable outcomes, with low rates of severe complications.

Broader Implications and Public Health Challenges

Despite these findings, uptake of the 2024–2025 (and subsequent) COVID-19 shots has been low — around 17–23% among U.S. adults, even lower in some groups. An accompanying editorial by former FDA Commissioner Robert Califf, MD, underscores a favorable benefit-risk profile but laments the impact of politicization and anti-vaccine rhetoric on public health.

Califf and Al-Aly note that while absolute benefits may be small for healthy young people, they are substantial for older adults and those with comorbidities. Vaccination decisions should be individualized, weighing personal risk factors against rare side effects.

Limitations of the Study

The VA cohort is predominantly older, male, and White, which limits direct generalizability to younger people, women, or more diverse populations. As an observational study, it cannot fully rule out all confounding factors, though researchers used robust statistical methods like weighting to balance groups. Many veterans had prior COVID vaccinations, reflecting real-world boosted populations.

A Balanced, Evidence-Based Perspective

COVID-19 vaccines are tools in a broader toolkit that includes hygiene, testing when symptomatic, and managing chronic conditions. For many, especially those at elevated cardiovascular risk, staying up to date with annual formulations offers layered protection — not just against acute illness but against longer-term complications like heart events.

As the virus continues circulating, this latest evidence reinforces that updated COVID-19 shots remain a net positive for heart health in key populations. Individuals should consult healthcare providers to assess their personal risks and benefits in light of the evolving data. Public health messaging that transparently communicates both benefits and rare risks will be crucial to rebuilding trust and informed decision-making.

In summary, amid updates and shifting perceptions, the heart-protective effects of COVID-19 vaccination endure, providing another compelling reason for vulnerable individuals to consider the annual shot alongside their flu vaccine.