Ziyad Al-Aly and colleagues found that the 2024–2025 vaccine was linked to a lower risk of major adverse cardiovascular events in more than 1 million veterans. The study in JAMA Internal Medicine followed those records for eight months after vaccination.
Among veterans who received the vaccine, the risk fell across heart attacks, strokes, heart failure hospitalizations and cardiovascular deaths. The researchers said the findings offer timely evidence for current discussions about updated COVID-19 vaccines.
Ziyad Al-Aly and JAMA Internal Medicine
Between September and December 2024, the researchers reviewed health records from veterans who received flu shots, and roughly one-third also received a COVID-19 vaccine the same day. That design gave the study a built-in comparison between vaccinated and unvaccinated veterans in the same season and under the same clinical setting.
The strongest reduction appeared in patients 75 or older and in those with chronic conditions. The study found a nearly 38% reduction in COVID-related cardiac events and a 24% decrease in all-cause cardiac events.
STAT News and under the weather
In an interview with STAT News, Ziyad Al-Aly said one explanation is that some people with undiagnosed COVID-19 may have brushed off early symptoms as being “under the weather” before a later cardiac event. That would help explain why the reduction in COVID-19–associated major adverse cardiovascular events was smaller than the reduction in all-cause MACE.
The researchers wrote that the vaccine’s protective association may extend to the hidden burden of undetected SARS-CoV-2 and its sequelae. They also said the findings provide timely evidence to help inform clinical and public health discussions about the role of updated COVID-19 vaccines in the current epidemiologic context.
COVID and Long COVID
The findings land against ongoing concerns about COVID and Long COVID, including fatigue, difficulty breathing and trouble with memory and thinking. COVID can also contribute to heart rhythm problems, blood clots and life-threatening heart failure through excessive inflammation.
For readers deciding what to do next, the study does not set a new rule or schedule a policy change. It instead adds a large real-world data point for people discussing whether the 2024–2025 vaccine may offer benefit beyond preventing infection, especially for older adults and those with chronic conditions.
