COVID vaccines still protect against heart problems, large study finds

Recent research indicates that updated COVID-19 vaccines still offer significant protection against heart-related issues, particularly among older adults and those with existing health conditions. Despite a decline in the uptake of seasonal COVID-19 vaccines among Americans, findings from a large-scale study reveal that these shots are crucial in preventing cardiovascular diseases. Conducted using data from over 1 million patients within the U.S. Department of Veterans Affairs (VA) healthcare system, the study reinforces earlier conclusions that COVID vaccines help mitigate risks of heart attacks and strokes associated with the virus. Published in JAMA Internal Medicine, the study specifically highlighted the effectiveness of the 2024–2025 COVID-19 vaccine in preventing major adverse cardiovascular events (MACE), a category that includes cardiovascular deaths, heart attacks, strokes, and hospitalizations due to heart failure. The analysis examined electronic medical records of 1,039,659 patients from the VA's St. Louis Health Care System. During the study period from September 3, 2024, to December 31, 2024, all participants received a seasonal flu vaccine, with a subset also receiving a COVID-19 vaccine. Out of the total patients, 349,085 were vaccinated with both vaccines, while 690,574 received only the flu shot, which served as the control group. After an eight-month follow-up, researchers assessed documented COVID-19 cases and compared the incidence of MACE events between the two groups. The results indicated a 38 percent effectiveness of the COVID vaccines against MACE events. Although the absolute benefit might seem small—lowering the rate of COVID-19-associated MACE events from approximately 5 in 10,000 to 3 in 10,000—the implications are particularly significant for older adults and those with pre-existing health issues, who showed the highest levels of protection.