What does a Covid-19 vaccine have to do with heart attack and stroke? A study with over 1 million veterans reveals an unexpected link between immunization, the heart, and seniors over 75 years old.

Written by Caio Aviz

Published on 18/06/2026 at 01:22

Updated on 18/06/2026 at 01:23

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Study with over 1 million American veterans shows a 38% drop in severe cardiovascular events linked to Covid-19, with stronger benefits among the elderly and people with comorbidities

The updated Covid-19 vaccine reduced the risk of severe cardiovascular events associated with the disease by about 38%, such as heart attack, stroke, heart failure, and cardiovascular death, according to a study published last Monday, June 15, in JAMA Internal Medicine.

The result was particularly noteworthy among people over 75 years old. In this group, the reduction in cardiovascular events reached 50.7%, according to researchers from the U.S. Department of Veterans Affairs and Washington University in St. Louis.

Study evaluated over 1 million American veterans

The research analyzed electronic records of more than 1 million American war veterans who received the flu vaccine between September and December 2024.

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Heart attack, stroke, and heart failure were monitored

During up to eight months of follow-up, researchers observed four severe cardiovascular outcomes related to Covid-19.

Among them were death from cardiovascular event, acute myocardial infarction, stroke, and hospitalization for heart failure.

According to the study, for every 10,000 vaccinated people, about two severe cardiovascular events associated with Covid-19 were prevented, compared to the group that only received the flu vaccine.

Additionally, when all cardiovascular events were considered, and not just those confirmed to be linked to Covid-19, the number rose to approximately 24 events prevented per 10,000 people.

Benefit was greater in the elderly and patients with pre-existing conditions

The average age of participants was 70 years. Even so, the most significant effect appeared among people over 75 years, a group in which there was a 50.7% reduction in cardiovascular events.

In other age groups, the results were not statistically significant. Therefore, it is not possible to confidently state that the vaccine protected these groups against cardiovascular episodes.

The study also showed significant relative efficacy in people with and without comorbidities. However, the absolute benefit was greater in individuals with pre-existing conditions.

The conditions mentioned included cardiovascular disease, chronic kidney disease, chronic lung disease, diabetes, and immunosuppression.

In a population of 1 million people, the authors estimate that vaccination could prevent about 1,580 deaths and 2,370 adverse cardiovascular events in eight months.

Why the vaccine may protect the heart

The research indicates that infection by SARS-CoV-2 can trigger processes of inflammation and coagulation in the body.

These mechanisms damage blood vessels and increase the risk of clot formation. These clots can cause a heart attack or stroke.

Thus, by reducing the severity of the infection, the vaccine also decreases the mechanisms linked to vascular damage.

Researchers urge caution in interpreting the data

Despite the results, the authors emphasize that the study is observational. Additionally, the analysis was conducted only with American veterans, a predominantly white, male, and elderly group.

The researchers also state that the current efficacy is lower than that observed in the early years of the pandemic. The explanation involves the evolution of the virus, immunity acquired from previous infections, and the lower frequency of testing.

Even so, the study reinforces that some cardiovascular complications caused by Covid-19 may occur in people who do not test positive for the disease.

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What does a Covid-19 vaccine have to do with heart attack and stroke? A study with over 1 million veterans reveals an unexpected link between immunization, the heart, and seniors over 75 years old.

Study with over 1 million American veterans shows a 38% drop in severe cardiovascular events linked to Covid-19, with stronger benefits among the elderly and people with comorbidities

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What does a Covid-19 vaccine have to do with heart attack and stroke? A study with over 1 million veterans reveals an unexpected link between immunization, the heart, and seniors over 75 years old.

Study with over 1 million American veterans shows a 38% drop in severe cardiovascular events linked to Covid-19, with stronger benefits among the elderly and people with comorbidities

Study evaluated over 1 million American veterans

Heart attack, stroke, and heart failure were monitored

Brazil looks to China and prepares an unprecedented issuance in yuan that could affect external debt, reduce dependence on the dollar, and open a new billion-dollar route for Asian investors.

Benefit was greater in the elderly and patients with pre-existing conditions

Why the vaccine may protect the heart

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Mother and daughter build a 70 m² house with more than 8,000 discarded glass bottles and impress with their creativity; known as the Casa de Sal, the property is located on Itamaracá Island, in Pernambuco.

The river that “dies” in the desert never reaches the sea and yet gives life to one of Africa’s largest natural refuges in a truly impressive way.

Libya built over 4,000 kilometers of underground pipelines to bring water from the Sahara to coastal cities in a project that the government itself called the Eighth Wonder of the World.

Desert sand, previously discarded for being too smooth for concrete, becomes an ecological brick in the United Arab Emirates, dispensing with Portland cement, curing at room temperature, and attempting to transform dunes useless for construction into raw material for a new arid engineering.

He transformed an abandoned plastic water tank into an underground house in the “hobbit hole” style, using only repurposed pallet wood, without heavy machinery or expensive labor.

China transforms desert-devastated area into the world’s largest artificial forest, planting trees for 60 years, blocking sand that reached Beijing, and creating a “green lung” of 92,000 hectares in a region once considered lost.

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