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The newest COVID-19 vaccine, released for the 2024–2025 season, is linked to a reduced risk of serious heart-related events among U.S. veterans, according to a large new study. The research, published in JAMA Internal Medicine, analyzed health records from over one million veterans and found that those who received the 2024–2025 COVID-19 vaccine along with their flu shot had a lower chance of experiencing major adverse cardiovascular events (MACE), which include heart attack, stroke, hospitalization for heart failure, or cardiovascular death.
According to the study led by researchers at the U.S. Department of Veterans Affairs, the vaccine was associated with a 37.7% reduction in COVID-related MACE over eight months. The benefit was especially notable in people aged 75 and older, who saw a 50.7% decrease in risk. Those with chronic health conditions also experienced greater absolute risk reductions compared to healthier individuals.
The analysis focused on veterans who received both the COVID-19 and influenza vaccines between September and December 2024, compared with veterans who received only the flu vaccine. The study design aimed to control for healthy vaccinee bias by including only those who were already getting the flu vaccine.
Secondary analyses found even larger reductions in all-cause MACE, hospitalization, and death, suggesting the vaccine’s protective effects may extend beyond just COVID-linked heart issues. The findings are consistent with previous research showing that vaccinations against infectious diseases can help reduce cardiovascular risks, likely by lowering the chance or severity of infection and the body’s inflammatory response.
Dr. Glenn Hirsch, a cardiologist at National Jewish Health in Denver, Colorado, told Fox News that the results were “not overall surprising,” since “vaccines either prevent infection or reduce the severity of infection and subsequent inflammation, lowering the cardiovascular risk.”
However, the study authors and outside experts note that these results show an association, not direct proof that the vaccine causes the reduced risk, since the study was observational and not a randomized trial. Protection was also seen to wane over time, and the overall benefit was somewhat smaller than in earlier years—possibly due to increased population immunity, milder COVID variants, and lower rates of testing.
A related study from the Centers for Disease Control and Prevention found that the updated COVID-19 vaccine also reduced emergency care visits and hospitalizations for COVID-related complications, especially within the first two months after vaccination, although effectiveness declined as more time passed.
Experts conclude that updated COVID-19 vaccines still provide meaningful protection against major clinical outcomes, especially in older adults and those with chronic health problems. They encourage people to discuss COVID-19 vaccination with their healthcare provider each year.